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  • 1
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 44 (9). pp. 2524-2546.
    Publication Date: 2015-05-28
    Description: In this study, the authors discuss two different parameterizations for the effect of mixed layer eddies, one based on ageostrophic linear stability analysis (ALS) and the other one based on a scaling of the potential energy release by eddies (PER). Both parameterizations contradict each other in two aspects. First, they predict different functional relationships between the magnitude of the eddy fluxes and the Richardson number (Ri) related to the background state. Second, they also predict different vertical structure functions for the horizontal eddy fluxes. Numerical simulations for two different configurations and for a large range of different background conditions are used to evaluate the parameterizations. It turns out that PER is better suited to capture the Ri dependency of the magnitude of the eddy fluxes. On the other hand, the vertical structure of the meridional eddy fluxes predicted by ALS is more accurate than that of PER, while the vertical structure of the vertical eddy fluxes is well predicted by both parameterizations. Therefore, this study suggests the use of the magnitude of PER and the vertical structure functions of ALS for an improved parameterization of mixed layer eddy fluxes.
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  • 2
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    AMS (American Meteorological Society)
    In:  Journal of the Atmospheric Sciences, 71 (4). pp. 1494-1507.
    Publication Date: 2017-10-24
    Description: Northern Hemisphere stratospheric variability is investigated with respect to chaotic behavior using time series from three different variables extracted from four different reanalysis products and two numerical model runs with different forcing. The time series show red spectra at all frequencies and the probability distribution functions show persistent deviations from a Gaussian distribution. An exception is given by the numerical model forced with perpetual winter conditions—a case that shows more variability and follows a Gaussian distribution, suggesting that the deviation from Gaussianity found in the observations is due to the transition between summer and winter variability. To search for the presence of a chaotic attractor the correlation dimension and entropy, the Lyapunov spectrum, and the associated Kaplan–Yorke dimension are estimated. A finite value of the dimensions can be computed for each variable and data product, with the correlation dimension ranging between 3.0 and 4.0 and the Kaplan–Yorke dimension between 3.3 and 5.5. The correlation entropy varies between 0.6 and 1.1. The model runs show similar values for the correlation and Lyapunov dimensions for both the seasonally forced run and the perpetual-winter run, suggesting that the structure of a possible chaotic attractor is not determined by the seasonality in the forcing, but must be given by other mechanisms.
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  • 3
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    AMS (American Meteorological Society)
    In:  Journal of the Atmospheric Sciences, 71 (12). pp. 4611-4620.
    Publication Date: 2017-10-24
    Description: Southern Hemisphere (SH) stratospheric variability is investigated with respect to chaotic behavior using time series from three different variables extracted from four different reanalysis products. The results are compared with the same analysis applied to the Northern Hemisphere (NH). The probability density functions (PDFs) for the SH show persistent deviations from a Gaussian distribution. The variability is given by white spectra for low frequencies, a slope of −1 for intermediate frequencies, and −3 slopes for high frequencies. Considering the time series for winter and summer separately, PDFs show a Gaussian distribution and the variability spectra change their slopes, indicating the role of the transition between winter and summer variability in shaping the time series. The correlation (D2) and the Kaplan–Yorke (DKY) dimensions are estimated. A finite value of the dimensions can be computed for each variable and data product, except for the NCEP zonal-mean zonal wind and temperature data, which violate the requirement D2 ≤ DKY, possibly owing to the presence of spurious trends and inconsistencies in the data. The value of D2 ranges between 2.6 and 3.9, while DKY ranges between 3.0 and 4.5. The results show that both D2 and DKY display large variability in their values both for different datasets and for different variables within the same dataset. The variability of the values of D2 and DKY thus leaves open the question about the existence of a low-dimensional attractor or if the finite dimensions of the system are the result of the projection of a larger attractor in a low-dimensional embedding space.
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  • 4
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    AMS (American Meteorological Society)
    In:  Journal of the Atmospheric Sciences, 71 (7). pp. 2674-2694.
    Publication Date: 2017-10-24
    Description: The sensitivities of the Brewer–Dobson circulation (BDC) to different distributions of tropical SST heating are investigated in an idealized aquaplanet model. It is found that an increase in tropical SSTs generally leads to an acceleration of tropical upwelling and an associated reduction in the age of air (AOA) in the polar stratosphere and that the AOA near the subtropical tropopause is correlated with local isentropic mixing of tropospheric air with stratospheric air. The zonal distribution of SST perturbations has a major impact on the vertical and meridional structure of the BDC as compared with other SST characteristics. Zonally localized SST heatings tend to generate a shallow acceleration of the stratospheric residual circulation, enhanced isentropic mixing associated with a weakened stratospheric jet, and a reduction in AOA mostly within the polar vortex. In contrast, SST heatings with a zonally symmetric structure tend to produce a deep strengthening of the stratospheric residual circulation, suppressed isentropic mixing associated with a stronger stratospheric jet, and a decrease of AOA in the entire stratosphere. The shallow versus deep strengthening of the stratospheric residual circulation change has been linked to wave propagation and dissipation in the subtropical lower stratosphere rather than wave generation in the troposphere, and the former can be strongly affected by the vertical position of the subtropical jet. These results suggest that, while the longitudinally localized SST trends under climate change may contribute to the change in the shallow branch of the BDC, the upward shift of the subtropical jet associated with the zonal SST heating can impact the deep branch of the BDC.
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  • 5
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    AMS (American Meteorological Society)
    In:  Journal of the Atmospheric Sciences, 71 (2). pp. 566-573.
    Publication Date: 2017-10-24
    Description: The authors test the hypothesis that recent observed trends in surface westerlies in the Southern Hemisphere are directly consequent on observed trends in the timing of stratospheric final warming events. The analysis begins by verifying that final warming events have an impact on tropospheric circulation in a simplified GCM driven by specified equilibrium temperature distributions. Seasonal variations are imposed in the stratosphere only. The model produces qualitatively realistic final warming events whose influence extends down to the surface, much like what has been reported in observational analyses. The authors then go on to study observed trends in surface westerlies composited with respect to the date of final warming events. If the considered hypothesis were correct, these trends would appear to be much weaker when composited with respect to the date of the final warming events. The authors find that this is not the case, and accordingly they conclude that the observed surface changes cannot be attributed simply to this shift toward later final warming events.
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  • 6
    Publication Date: 2020-08-04
    Description: Precipitation is highly variable in space and time; hence, rain gauge time series generally exhibit additional random small-scale variability compared to area averages. Therefore, differences between daily precipitation statistics simulated by climate models and gauge observations are generally not only caused by model biases, but also by the corresponding scale gap. Classical bias correction methods, in general, cannot bridge this gap; they do not account for small-scale random variability and may produce artifacts. Here, stochastic model output statistics is proposed as a bias correction framework to explicitly account for random small-scale variability. Daily precipitation simulated by a regional climate model (RCM) is employed to predict the probability distribution of local precipitation. The pairwise correspondence between predictor and predictand required for calibration is ensured by driving the RCM with perfect boundary conditions. Wet day probabilities are described by a logistic regression, and precipitation intensities are described by a mixture model consisting of a gamma distribution for moderate precipitation and a generalized Pareto distribution for extremes. The dependence of the model parameters on simulated precipitation is modeled by a vector generalized linear model. The proposed model effectively corrects systematic biases and correctly represents local-scale random variability for most gauges. Additionally, a simplified model is considered that disregards the separate tail model. This computationally efficient model proves to be a feasible alternative for precipitation up to moderately extreme intensities. The approach sets a new framework for bias correction that combines the advantages of weather generators and RCMs.
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  • 7
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    AMS (American Meteorological Society)
    In:  Bulletin of the American Meteorological Society, 95 (2). pp. 293-296.
    Publication Date: 2019-09-23
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  • 8
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 44 (1). pp. 3-23.
    Publication Date: 2018-04-12
    Description: There is an ongoing discussion in the community concerning the wave-averaged momentum equations in the hybrid vertically Lagrangian and horizontally Eulerian (VL) framework and, in particular, the form stress term (representing the residual effect of pressure perturbations) which is thought to restrict the handling of higher order waves in terms of a perturbation expansion. The present study shows that the traditional pressure-based form stress term can be transformed into a set of terms that do not contain any pressure quantities but do contain the time derivative of a wave-induced velocity. This wave-induced velocity is referred to as the pseudomomentum in the VL framework, as it is analogous to the generalized pseudomomentum in Andrews and McIntyre. This enables the second expression for the wave-averaged momentum equations in the VL framework (this time for the development of the total transport velocity minus the VL pseudomomentum) to be derived together with the vortex force. The velocity-based expression of the form stress term also contains the residual effect of the turbulent viscosity, which is useful for understanding the dissipation of wave energy leading to transfer of momentum from waves to circulation. It is found that the concept of the virtual wave stress of Longuet-Higgins is applicable to quite general situations: it does not matter whether there is wind forcing or not, the waves can have slow variations, and the viscosity coefficient can vary in the vertical. These results provide a basis for revisiting the surface boundary condition used in numerical circulation models.
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  • 9
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 44 (2). pp. 445-463.
    Publication Date: 2020-08-04
    Description: Mooring observations and model simulations point to an instability of the Labrador Current (LC) during winter, with enhanced eddy kinetic energy (EKE) at periods between 2 to 5 days, and much less EKE during other seasons. Linear stability analysis using vertical shear and stratification from the model reveals three dominant modes of instability in the LC: - a balanced interior mode with along-flow wavelengths of about 30–45 km, phase velocities of 0.3 m/s, maximal growth rates of 1 d−1 and surface intensified, but deep reaching amplitudes, - a balanced shallow mode with along-flow wavelengths of about 0.3–1.5 km, about three times larger phase speeds and growth rates, but amplitudes confined to the mixed layer (ML), - and an unbalanced symmetric mode with largest growth rates, vanishing phase speeds and along-flow structure, and very small cross-flow wavelengths, also confined to the ML. Both balanced modes are akin to baroclinic instability, but operate at moderate to small Richardson numbers Ri with much larger growth rates as for the quasi-geostrophic limit of Ri ≫ 1. The interior mode is found to be responsible for the instability of the LC during winter. Weak stratification and enhanced vertical shear due to local buoyancy loss and the advection of convective water masses from the interior result in small Ri within the LC, and to three times larger growth rates of the interior mode in March compared to summer and fall conditions. Both the shallow and the symmetric mode are not resolved by the model, but it is suggested that they might also play an important role for the instability in the LC and for lateral mixing.
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  • 10
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 44 (2). pp. 482-491.
    Publication Date: 2020-08-04
    Description: Sensible and latent heat fluxes were estimated from turbulence measurements gathered during several Atlantic transects of the R/V Polarstern. The inertial dissipation method was used to analyze the data. Resulting bulk transfer coefficients were then applied to the data from the ship’s meteorological system to get continuous time series of the heat fluxes. Combined to the measured downward solar and longwave radiation fluxes allows for an estimate of the total energy budget at the air-sea interface. Comparing these parameterized energy fluxes to ones based on the COARE 3.0 bulk flux algorithm show very strong agreement.
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  • 11
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    AMS (American Meteorological Society)
    In:  Journal of the Atmospheric Sciences, 71 (6). pp. 2264-2279.
    Publication Date: 2020-08-04
    Description: The dynamical origin of the spectral and autocorrelation structure of annular variability in the troposphere is investigated by a deductive approach. Specifically, the structure of the power spectrum and autocorrelation function of the zonal-mean geopotential is analyzed for the case of a quasigeostrophic spherical atmosphere subject to a white noise mechanical forcing applied in a single Hough mode and concentrated at a particular level in the vertical, with vertically uniform Newtonian cooling and Rayleigh drag concentrated at a rigid lower boundary. Analytic expressions for the power spectrum are presented together with expressions for an approximate red noise (i.e., a Lorentzian-shaped) power spectrum. It is found that for an infinitely deep atmosphere the power spectrum can be well approximated by a red noise process for the first few Hough modes (associated with large Rossby heights), provided the distance from the forcing is not larger than about one Rossby height. When a frictional rigid lower boundary is included, however, the approximation is generally bad. The high-frequency part of the power spectrum exhibits near-exponential behavior and the autocorrelation function shows a transition from a rapid decay at short lags to a much slower decay at longer lags, if the thermal and mechanical damping time scales are sufficiently well separated. Since observed annular variability exhibits the same characteristics, the above results lead to the hypothesis that these characteristics may, to some extent, be intrinsic to the linear zonal-mean response problem—although the need for an additional contribution from eddy feedbacks is also implied by the results.
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  • 12
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 44 . pp. 2485-2497.
    Publication Date: 2020-08-04
    Description: A representation of an equatorial basin mode excited in a shallow water model for a single high order baroclinic vertical normal mode is used as a simple model for the equatorial deep jets. The model is linearized about both a state of rest and a barotropic mean flow corresponding to the observed Atlantic Equatorial Intermediate Current System. We found that the eastward mean flow associated with the North and South Intermediate Counter Currents (NICC and SICC, respectively) effectively shields the Equator from off-equatorial Rossby waves. The westward propagation of these waves is blocked and focusing on the Equator due to beta dispersion is prevented. This leads to less energetic jets along the Equator. On the other hand, the westward barotropic mean flow along the Equator reduces the gradient of absolute vorticity and hence widens the cross-equatorial structure of the basin mode. Increasing lateral viscosity predominantly affects the width of the basin modes’ Kelvin wave component in the presence of the mean flow while the Rossby wave is confined by the flanking NICC and SICC. Independent of the presence of the mean flow, the application of sufficient lateral mixing also hinders the focusing of off-equatorial Rossby waves, which is hence an unlikely feature of a low-frequency basin mode in the real ocean.
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  • 13
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 27 (7). pp. 2577-2587.
    Publication Date: 2014-10-22
    Description: A decadal change in the character of ENSO was observed around year 2000 toward weaker-amplitude, higher-frequency events with an increased occurrence of central Pacific El Niños. Here these changes are assessed in terms of the Bjerknes stability index (BJ index), which is a measure of the growth rate of ENSO-related SST anomalies. The individual terms of the index are calculated from ocean reanalysis products separately for the time periods 1980–99 and 2000–10. The spread between the products is large, but they show a robust weakening of the thermocline feedback due to a reduced thermocline slope response to anomalous zonal wind stress as well as a weakened wind stress response to eastern equatorial Pacific SST anomalies. These changes are consistent with changes in the background state of the tropical Pacific: cooler mean SST in the eastern and central equatorial Pacific results in reduced convection there together with a westward shift in the ascending branch of the Walker circulation. This shift leads to a weakening in the relationship between eastern Pacific SST and longitudinally averaged equatorial zonal wind stress. Also, despite a steeper mean thermocline slope in the more recent period, the thermocline slope response to wind stress anomalies weakened due to a smaller zonal wind fetch that results from ENSO-related wind anomalies being more confined to the western basin. As a result, the total BJ index is more negative, corresponding to a more strongly damped system in the past decade compared to the 1980s and 1990s.
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  • 14
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 27 (4). pp. 1821-1825.
    Publication Date: 2017-08-25
    Description: In his comment, G. Bürger criticizes the conclusion that inflation of trends by quantile mapping is an adverse effect.He assumes that the argument would be ‘‘based on the belief that long-term trends and along with them future climate signals are to be large scale.’’ His line of argument reverts to the so-called inflated regression. Here it is shown, by referring to previous critiques of inflation and standard literature in statistical modeling as well as weather forecasting, that inflation is built upon a wrong understanding of explained versus unexplained variability and prediction versus simulation. It is argued that a sound regressionbased downscaling can in principle introduce systematic local variability in long-term trends, but inflation systematically deteriorates the representation of trends. Furthermore, it is demonstrated that inflation by construction deteriorates weather forecasts and is not able to correctly simulate small-scale spatiotemporal structure.
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  • 15
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 44 (7). pp. 1776-1797.
    Publication Date: 2018-04-12
    Description: The relationship between the Agulhas Current and the Agulhas leakage is not well understood. Here, this is investigated using two basin-scale and two global ocean models, of incrementally increasing resolution. The response of the Agulhas Current is evaluated under a series of sensitivity experiments, in which idealised anomalies, designed to geometrically modulate zonal trade wind stress, are applied across the Indian Ocean basin. The imposed wind stress changes exceed ±2 standard deviations from the annual mean trade winds and, in the case of intensification, are partially representative of recently observed trends. The Agulhas leakage is quantified using complimentary techniques based on Lagrangian virtual floats and Eulerian passive tracer flux. As resolution increases, model behavior converges and the sensitivity of the leakage to Agulhas Current transport anomalies is reduced. In the two eddy-resolving configurations tested, the leakage is insensitive to changes in Agulhas Current transport at 32°S, though substantial eddy kinetic energy anomalies are evident. Consistent with observations, the position of the retroflection remains stable. The decoupling of Agulhas Current variability from the Agulhas leakage suggests that, while correlations between the two may exist, they may not have a clear dynamical basis. It is suggested that present and future Agulhas leakage proxies be considered in the context of potentially transient forcing regimes.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
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  • 16
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 27 . pp. 9101-9122.
    Publication Date: 2015-11-24
    Description: A surface diurnal warm layer is diagnosed from Seaglider observations, and develops on half the days in the CINDY/DYNAMO Indian Ocean experiment. The diurnal warm layer occurs on days of high solar radiation flux (〉 80 W m−2) and low wind speed (〈 6 m s−1), and preferentially in the inactive stage of the Madden–Julian Oscillation. Its diurnal harmonic has an exponential vertical structure with a depth scale of 4–5 m (dependent on chlorophyll concentration), consistent with forcing by absorption of solar radiation. The effective sea surface temperature (SST) anomaly due to the diurnal warm layer often reaches 0.8°C in the afternoon, with a daily mean of 0.2°C, rectifying the diurnal cycle onto longer time scales. This SST anomaly drives an anomalous flux of 4 W m−2 that cools the ocean. Alternatively, in a climate model where this process is unresolved, this represents an erroneous flux that warms the ocean. A simple model predicts a diurnal warm layer to occur on 30–50% of days across the tropical warm pool. On the remaining days, with low solar radiation and high wind speeds, a residual diurnal cycle is observed by the Seaglider, with a diurnal harmonic of temperature that decreases linearly with depth. As wind speed increases, this already weak temperature gradient decreases further, tending towards isothermal conditions.
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  • 17
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 27 (21). pp. 8135-8150.
    Publication Date: 2020-08-04
    Description: Sea surface temperature (SST) anomalies in the eastern equatorial Atlantic are connected to modulations in the strength of the South Atlantic subtropical high-pressure system, referred to as the South Atlantic Anticyclone (SAA). Using ocean and atmosphere reanalysis products we show here that the strength of the SAA from February to May impacts the timing of the cold tongue onset and the intensity of its development in the eastern equatorial Atlantic (EEA) via anomalous tropical wind power. This modulation of the timing and amplitude of the seasonal cold tongue development manifests as anomalous SST events peaking between June and August. The timing and impact of this connection is not completely symmetric for warm and cold events. For cold events, an anomalously strong SAA in February and March leads to positive wind power anomalies from February to June resulting in an early cold tongue onset and subsequent cold SST anomalies in June and July. For warm events the anomalously weak SAA persists until May, generating negative wind power anomalies that lead to a late cold tongue onset as well as a suppression of the cold tongue development and associated warm SST anomalies. Mechanisms by which SAA induced wind power variations south of the equator influence EEA SST are discussed, including ocean adjustment via Rossby and Kelvin wave propagation, meridional advection, and local intraseasonal wind variations
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  • 18
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    AMS (American Meteorological Society)
    In:  Journal of Atmospheric and Oceanic Technology, 31 (1). pp. 181-196.
    Publication Date: 2020-08-04
    Description: We present a detailed quality assessment of a novel underwater sensor for the measurement of CO2 partial pressure (pCO2) based on surface water field deployments carried out between 2008 and 2011. The commercially available sensor, which is based on membrane equilibration and NDIR spectrometry is small and can be integrated into mobile platforms. It is calibrated in water against a proven flow-through pCO2 instrument within a custom-built calibration setup. The aspect of highest concern with respect to achievable data quality of the sensor is the compensation for signal drift inevitably connected to absorption measurements. We use three means to correct for drift effects: (i) a filter correlation or dual-beam setup, (ii) regular zero gas measurements realized automatically within the sensor and (iii) a zero-based transformation of two sensor calibrations flanking the time of sensor deployment. Three sensors were tested against an underway pCO2 system during two major research cruises providing an in situ temperature range from 7.4 to 30.1°C and pCO2 values between 289 and 445 μatm. The average difference between sensor and reference pCO2 was found to be -0.6 ± 3 μatm with a RMSE of 3.7 μatm.
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  • 19
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 27 (3). pp. 977-993.
    Publication Date: 2019-01-08
    Description: Ammassalik in southeast Greenland is known for strong wind events that can reach hurricane intensity and cause severe destruction in the local town. Yet, these winds and their impact on the nearby fjord and shelf region have not been studied in detail. Here, data from two meteorological stations and the European Centre for Medium-Range Weather Forecasts Interim Re-Analysis (ERA-Interim) are used to identify and characterize these strong downslope wind events, which are especially pronounced at a major east Greenland fjord, Sermilik Fjord, within Ammassalik. Their local and regional characteristics, their dynamics and their impacts on the regional sea ice cover, and air–sea fluxes are described. Based on a composite of the events it is concluded that wind events last for approximately a day, and seven to eight events occur each winter. Downslope wind events are associated with a deep synoptic-scale cyclone between Iceland and Greenland. During the events, cold dry air is advected down the ice sheet. The downslope flow is accelerated by gravitational acceleration, flow convergence inside the Ammassalik valley, and near the coast by an additional thermal and synoptic-scale pressure gradient acceleration. Wind events are associated with a large buoyancy loss over the Irminger Sea, and it is estimated that they drive one-fifth of the net wintertime loss. Also, the extreme winds drive sea ice out of the fjord and away from the shelf.
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  • 20
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    AMS (American Meteorological Society)
    In:  Bulletin of the American Meteorological Society, 95 (7). S1-S279.
    Publication Date: 2019-07-10
    Description: In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns' around the world. This follows several years dominated by the effects of either La Nina. or El Nino events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earth's surface and through the troposphere. Some regions in the Southern Hemispherehad record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957 At the opposite pole, the Arctic observed its seventh warmest year since record's began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope Of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during Winter across Eurasia were followed by warm Spring temperature anomalies, which, were linked to a new record Eurasian snow cover extent in the May. Minimum sea ice extent in the :Arctic was the sixth lowest since satellite Observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years Antarctica, on the other hand, had above average sea ice extent throughout 2013, with 116 days Of new daily high extent records, inclding a new daily maximum sea ice area of 19.57 million km(2) reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013: The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt Content in near-surface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3,2 mm yr(-1) over the past two decades. A portion of this trend (0.5 mm yr(-1)) has been attributed to natural variability associated with the Pacific decadal oscillation as Well as to ongoing contribution from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical Cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (OS m s(-1)) on 7 November, the highest Wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan at it Made landfall over the central Philippines, an area where sea level is currently at historic highs increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all Continued to increase in 2013. As in previous our years, each of these Major greenhouse gases once again reached historic high Concentrations. In the Arctic carbon dioxide and methane:, Increased at the same rate as:the global increase. These increases are likely due to export from lower latitudes rather than a consequence Of increases in Arctic sources such as thawing permafrost., At Mauna Loa, Hawaii, for the first time since measurement began in 1958, the daily average Mixing ratio Of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th, edition of the State of the Climate series
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  • 21
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 43 (12). pp. 2611-2628.
    Publication Date: 2021-06-17
    Description: The Denmark Strait Overflow (DSO) supplies about one-third of the North Atlantic Deep Water and is critical to global thermohaline circulation. Knowledge of the pathways of DSO through the Irminger Basin and its transformation there is still incomplete, however. The authors deploy over 10 000 Lagrangian particles at the Denmark Strait in a high-resolution ocean model to study these issues. First, the particle trajectories show that the mean position and potential density of dense waters cascading over the Denmark Strait sill evolve consistently with hydrographic observations. These sill particles transit the Irminger Basin to the Spill Jet section (65.25°N) in 5–7 days and to the Angmagssalik section (63.5°N) in 2–3 weeks. Second, the dense water pathways on the continental shelf are consistent with observations and particles released on the shelf in the strait constitute a significant fraction of the dense water particles recorded at the Angmagssalik section within 60 days (~25%). Some particles circulate on the shelf for several weeks before they spill off the shelf break and join the overflow from the sill. Third, there are two places where the water density following particle trajectories decreases rapidly due to intense mixing: to the southwest of the sill and southwest of the Kangerdlugssuaq Trough on the continental slope. After transformation in these places, the overflow particles exhibit a wide range of densities.
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  • 22
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 26 (6). pp. 2137-2143.
    Publication Date: 2020-08-04
    Description: Quantile mapping is routinely applied to correct biases of regional climate model simulations compared to observational data. If the observations are of similar resolution as the regional climate model, quantile mapping is a feasible approach. However, if the observations are of much higher resolution, quantile mapping also attempts to bridge this scale mismatch. Here, it is shown for daily precipitation that such quantile mapping-based downscaling is not feasible but introduces similar problems as inflation of perfect prognosis ("prog") downscaling: the spatial and temporal structure of the corrected time series is misrepresented, the drizzle effect for area means is overcorrected, area-mean extremes are overestimated, and trends are affected. To overcome these problems, stochastic bias correction is required.
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  • 23
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 43 . pp. 149-164.
    Publication Date: 2018-04-12
    Description: Previous attempts to derive the depth-dependent expression of the radiation stress have lead to a debate concerning (i) the applicability of Mellor’s approach to a sloping bottom, (ii) the introduction of the delta function at the mean sea surface in the later papers by Mellor, and (iii) a wave-induced pressure term derived in several recent studies. The authors use an equation system in vertically Lagrangian and horizontally Eulerian (VL) coordinates suitable for a concise treatment of the surface boundary, and obtain an expression for the depth-dependent radiation stress that is consistent with the vertically-integrated expression given by Longuet-Higgins and Stewart. Concerning (i)-(iii) in the above, the difficulty of handling a sloping bottom disappears when wave-averaged momentum equations in the VL coordinates are written for the development of (not the Lagrangian mean velocity but) the Eulerian mean velocity. There is also no delta function at the sea surface in the expression for the depth-dependent radiation stress. The connection between the wave-induced pressure term in the recent studies and the depth-dependent radiation stress term is easily shown by rewriting the pressure-based form stress term in the thickness-weighted-mean (TWM) momentum equations as a velocity-based term which contains the time derivative of the pseudomomentum in the TWM framework.
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  • 24
    Publication Date: 2018-07-04
    Description: The upper ocean, including the biologically productive euphotic zone and the mixed layer, has great relevance for studies of physical, biogeochemical, and ecosystem processes and their interaction. Observing this layer with a continuous presence, sampling many of the relevant variables, and with sufficient vertical resolution, has remained a challenge. Here a system is presented which can be deployed on the top of deep-ocean moorings, with a drive mechanism at depths of 150-200m, which mechanically winches a large sensor float and smaller communications float tethered above it to the surface and back down again, typically twice per day for periods up to 1 year. The sensor float can carry several sizeable sensors, and it has enough buoyancy to reach the near surface and for the communications float to pierce the surface even in the presence of strong currents. The system can survive mooring blow-over to 1000m depth. The battery-powered design is made possible by using a balanced energy-conserving principle. Reliability is enhanced with a drive assembly that employs a single rotating part that has no slip rings or rotating seals. The profiling bodies can break the surface to sample the near-surface layer and to establish satellite communication for data relay or reception of new commands. An inductive pass-through mode allows communication with other mooring components throughout the water column beneath the system. A number of successful demonstration deployments have been completed.
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  • 25
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    AMS (American Meteorological Society)
    In:  Journal of Atmospheric and Oceanic Technology, 30 . pp. 112-126.
    Publication Date: 2020-08-04
    Description: In recent years, profiling floats, which form the basis of the successful international Argo observatory, are also being considered as platforms for marine biogeochemical research. This study showcases the utility of floats as a novel tool for combined gas measurements of CO2 partial pressure (pCO2) and O2. These float prototypes were equipped with a small-sized and submersible pCO2 sensor and an optode O2 sensor for high resolution measurements in the surface ocean layer. Four consecutive deployments were carried out during Nov. 2010 and June 2011 near the Cape Verde Ocean Observatory (CVOO) in the eastern tropical North Atlantic. The profiling float performed upcasts every 31 h while measuring pCO2, O2, salinity, temperature and hydrostatic pressure in the upper 200 m of the water column. In order to maintain accuracy, regular pCO2 sensor zeroings at depth and surface, as well as optode measurements in air, were performed for each profile. Through the application of data processing procedures (e.g., time-lag correction) accuracies of float-borne pCO2 measurements were greatly improved (10 – 15 μatm for water column and 5 μatm for surface measurements). O2 measurements yielded an accuracy of 2 μmol kg−1. First results of this pilot study show the possibility of using profiling floats as a platform for detailed and unattended observations of the marine carbon and oxygen cycle dynamics.
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  • 26
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 26 . pp. 7650-7661.
    Publication Date: 2020-08-04
    Description: The use of a coupled ocean/atmosphere/sea-ice model to hindcast (i.e. historical forecast) recent climate variability is described and illustrated for the cases of the 1976/77 and 1998/99 climate shift events in the Pacific. The initialization is achieved by running the coupled model in partially coupled mode whereby global observed wind stress anomalies are used to drive the ocean/sea-ice component of the coupled model while maintaining the thermodynamic coupling between the ocean/sea-ice and atmosphere components. Here we show that hindcast experiments can successfully capture many features associated with the 1976/77 and 1998/99 climate shifts. For instance, hindcast experiments started from the beginning of 1976 can capture sea surface temperature (SST) warming in the central-eastern equatorial Pacific and the positive phase of the Pacific Decadal Oscillation (PDO) throughout the 9 years following the 1976/77 climate shift, including the deepening of the Aleutian low pressure system. Hindcast experiments started from the beginning of 1998 can also capture part of the anomalous conditions during the 4 years after the 1998/99 climate. We argue that the dynamical adjustment of heat content anomalies that are present in the initial conditions in the tropics is important for the successful hindcast of the two climate shifts.
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  • 27
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    AMS (American Meteorological Society)
    In:  Invertebrate Biology, 132 (4). pp. 386-393.
    Publication Date: 2016-11-01
    Description: One of the most remarkable features of the reproductive systems of eubrachyuran crabs is the presence of specialized organs for sperm storage, the seminal receptacles. Descriptions of seminal receptacle morphology, sperm storage time, sperm retention across molts, and the capacity to store multiple ejaculates from different males can help in understanding crab mating strategies as well as in preventing negative effects of male-biased fisheries of heavily harvested species. Metacarcinus edwardsii is the most harvested crab in Chile, but its reproductive biology is largely unstudied. In this study, the morphology of the seminal receptacles of M. edwardsii is characterized from the macroscopic to the microscopic level, during key points in the reproductive cycle. The receptacles of experimentally mated and wild-caught females were included in this analysis. Metacarcinus edwardsii has ventral-type seminal receptacles that are able to retain sperm after molting, and even after extrusion of the eggs. Stratification of multiple ejaculates is clearly observed. In general, the pattern of sperm storage indicates that populations of this species, like those of other cancrid crabs, could have high resilience to the negative effects of the selective harvest of males, principally because females have a great sperm storage capacity.
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  • 28
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 44 (1). pp. 202-219.
    Publication Date: 2015-07-24
    Description: The Arctic continental shelf seas hold a globally significant source of freshwater that impacts Arctic Ocean stratification, circulation, and climate. This freshwater can be injected below the surface mixed layer by intense turbulent kinetic energy dissipation events, as resolved by Laptev Sea microstructure observations. The tides provide a major source of energy that can be dissipated and hence drive diapycnal mixing in the Laptev Sea. Multiyear ADCP mooring records from locations across the shelf reveal that semidiurnal tides are dominated by theM2 and S2 constituents, with the largest amplitudes on the outer shelf. Throughoutmost of the shelf, tides are clockwise polarized and sheared by stratification, as characteristic near the M2 critical latitude. Interannual variations of the tidal and shear structures on the inner shelf aremainly determined by the stratification-setting Lena River freshwater plume. In all locations,M2 tides are enhanced under sea ice, and therefore changes in the seasonal ice cover may lead to changes in tides and water column structure. The main conclusions of this study are that (i) tides play a comparatively greater role year-round on the outer shelf relative to the inner shelf; (ii) a sea ice reduction will overall decrease the predictability of the currents, especially on the inner shelf; and (iii) the freshwater distribution directly impacts diapycnal mixing by setting the vertical tidal structure. These combined effects imply that future sea ice loss will increase the variability and vertical mixing of freshwater, particularly on the inner shelf, where the Lena River first enters the Laptev Sea.
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  • 29
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    AMS (American Meteorological Society)
    In:  Journal of Atmospheric and Oceanic Technology, 30 . pp. 2820-2837.
    Publication Date: 2014-07-30
    Description: A large number of quantities have to be measured and processed to determine the atmospheric-state variables, which are the actual measurands, from aircraft-based measurements. A great part of the dependencies between these quantities depends on the aerodynamic state of the aircraft. Aircraft-based meteorological measurements, hence, require in-flight calibration. Most operators of research aircraft perform some kind of calibration, but the schemes used and the degree they are documented greatly vary. The flight maneuvers and calculation methods required, however, are published in a number of partly overlapping and partly contradictory publications. Some methods are only presented as a minor issue in publications mainly focused on atmospheric processes and are therefore hard to find. For an aircraft user, it is hence challenging to either perform or verify a calibration because of missing comprehensive guidance. This lack was stated on occasion of the in-flight calibration of the German research aircraft Polar5 carried out for the field experiment Investigation of Katabatic Winds and Polynyas during Summer (IKAPOS). In the present paper, a comprehensive review of the existing literature on this field and a practical guide to the wind calibration of a research aircraft to be used for turbulent flux measurements are given.
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  • 30
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    AMS (American Meteorological Society)
    In:  Journal of the Atmospheric Sciences, 70 (12). pp. 3959-3976.
    Publication Date: 2018-04-16
    Description: Accurate projections of stratospheric ozone are required because ozone changes affect exposure to ultraviolet radiation and tropospheric climate. Unweighted multimodel ensemble-mean (uMMM) projections from chemistry–climate models (CCMs) are commonly used to project ozone in the twenty-first century, when ozone-depleting substances are expected to decline and greenhouse gases are expected to rise. Here, the authors address the question of whether Antarctic total column ozone projections in October given by the uMMM of CCM simulations can be improved by using a process-oriented multiple diagnostic ensemble regression (MDER) method. This method is based on the correlation between simulated future ozone and selected key processes relevant for stratospheric ozone under present-day conditions. The regression model is built using an algorithm that selects those process-oriented diagnostics that explain a significant fraction of the spread in the projected ozone among the CCMs. The regression model with observed diagnostics is then used to predict future ozone and associated uncertainty. The precision of the authors’ method is tested in a pseudoreality; that is, the prediction is validated against an independent CCM projection used to replace unavailable future observations. The tests show that MDER has higher precision than uMMM, suggesting an improvement in the estimate of future Antarctic ozone. The authors’ method projects that Antarctic total ozone will return to 1980 values at around 2055 with the 95% prediction interval ranging from 2035 to 2080. This reduces the range of return dates across the ensemble of CCMs by about a decade and suggests that the earliest simulated return dates are unlikely.
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  • 31
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 26 . pp. 7767-7782.
    Publication Date: 2020-08-04
    Description: Evidence is presented for the notion that some contribution to the recent decadal trends observed in the Southern Hemisphere, including the lack of a strong Southern Ocean surface warming, may have originated from longer-term internal centennial variability originating in the Southern Ocean. The existence of such centennial variability is supported by the instrumental sea surface temperatures (SSTs), a multimillennial reconstruction of Tasmanian summer temperatures from tree rings, and a millennial control integration of the Kiel Climate Model (KCM). The model variability was previously shown to be linked to changes in Weddell Sea deep convection. During phases of deep convection the surface Southern Ocean warms, the abyssal Southern Ocean cools, Antarctic sea ice extent retreats, and the low-level atmospheric circulation over the Southern Ocean weakens. After the halt of deep convection the surface Southern Ocean cools, the abyssal Southern Ocean warms, Antarctic sea ice expands, and the low-level atmospheric circulation over the Southern Ocean intensifies, consistent with what has been observed during the recent decades. A strong sensitivity of the time scale to model formulation is noted. In the KCM, the centennial variability is associated with global-average surface air temperature (SAT) changes of the order of a few tenths of a degree per century. The model results thus suggest that internal centennial variability originating in the Southern Ocean should be considered in addition to other internal variability and external forcing when discussing the climate of the twentieth century and projecting that of the twenty-first century.
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  • 32
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    In:  Journal of the Atmospheric Sciences, 70 (7). pp. 2103-2118.
    Publication Date: 2020-08-04
    Description: The wintertime northern annular mode (NAM) at the surface is known to undergo slow intraseasonal variations in association with stratospheric variability, which leads the surface signal by up to several weeks. The relative contributions, however, of potentially relevant stratosphere–troposphere coupling mechanisms are not yet fully understood. In this study the relative roles of (i) the downward effect of the zonal-mean secondary circulation induced by quasigeostrophic (QG) adjustment to stratospheric wave drag and radiative damping and (ii) wave drag local to the troposphere are estimated. For this purpose, a spectral tendency equation of the QG zonal-mean zonal wind is derived and used, in a first step, to obtain the external mechanical forcing that, in the QG framework, drives exactly the observed stratospheric and tropospheric daily NAM. In a second step, the equation is then integrated in time to reconstruct the daily NAM, but with the forcing restricted to either stratospheric or tropospheric levels, each case leaving a characteristic NAM surface signal. The relative roles of the above-mentioned mechanisms are found to be of similar quantitative importance, but to differ in a qualitative sense. The downward effect of stratospheric QG adjustment is responsible for the initiation of the NAM surface signal, whereas subsequently local tropospheric wave drag actively maintains and persists the signal over several weeks. Furthermore, the downward effect of QG adjustment to stratospheric radiative damping is shown to have only a minor impact, compared to that from stratospheric wave drag. The robustness of these conclusions is demonstrated by a sensitivity study with respect to various model parameters.
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  • 33
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 43 (10). pp. 2113-2131.
    Publication Date: 2020-08-04
    Description: The Agulhas Current plays a crucial role in the thermohaline circulation through its leakage into the South Atlantic. Under both past and present climates, the trade winds and westerlies could have the ability to modulate the amount of Indian-Atlantic inflow. Compelling arguments have been put forward suggesting that trade winds alone have little impact on the magnitude of Agulhas leakage. Here, employing three ocean models for robust analysis – a global coarse resolution, a regional eddy-permitting and a nested high-resolution eddy-resolving configuration – and systematically altering the position and intensity of the westerly wind belt in a series of sensitivity experiments, it is shown that the westerlies, in particular their intensity, control the leakage. Leakage responds proportionally to the westerlies intensity up to a certain point. Beyond this, through the adjustment of the large-scale circulation, energetic interactions occur between the Agulhas Return Current and the Antarctic Circumpolar Current that result in a state where leakage no longer increases. This adjustment takes place within 1 to 2 decades. Contrary to previous assertions, our results further show that an equatorward (poleward) shift in westerlies increases (decreases) leakage. This occurs due to the redistribution of momentum input by the winds. It is concluded that the reported present-day leakage increase could therefore reflect an unadjusted oceanic response mainly to the strengthening westerlies over the last few decades.
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  • 34
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    In:  Bulletin of the American Meteorological Society, 94 (8). S1-S258.
    Publication Date: 2019-07-09
    Description: For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across global land and ocean surfaces ranked among the 10 warmest years on record. The global land surface temperature alone was also among the 10 warmest on record. In the upper atmosphere, the average stratospheric temperature was record or near-record cold, depending on the dataset. After a 30-year warming trend from 1970 to 1999 for global sea surface temperatures, the period 2000-12 had little further trend. This may be linked to the prevalence of La Ni a-like conditions during the 21st century. Heat content in the upper 700 m of the ocean remained near record high levels in 2012. Net increases from 2011 to 2012 were observed at 700-m to 2000-m depth and even in the abyssal ocean below. Following sharp decreases in to the effects of La Ni a, sea levels rebounded to reach records highs in 2012. The increased hydrological cycle seen in recent years continued, with more evaporation in drier locations and more precipitation in rainy areas. In a pattern that has held since 2004, salty areas of the ocean surfaces and subsurfaces were anomalously salty on average, while fresher areas were anomalously fresh. Global tropical cyclone activity during 2012 was near average, with a total of 84 storms compared with the 1981-2010 average of 89. Similar to 2010 and 2011, the North Atlantic was the only hurricane basin that experienced above-normal activity. In this basin, Sandy brought devastation to Cuba and parts of the eastern North American seaboard. All other basins experienced either near-or below-normal tropical cyclone activity. Only three tropical cyclones reached Category 5 intensity-all in Bopha became the only storm in the historical record to produce winds greater than 130 kt south of 7 N. It was also the costliest storm to affect the Philippines and killed more than 1000 residents. Minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June both reached new record lows. June snow cover extent is now declining at a faster rate (-17.6% per decade) than September sea ice extent (-13.0% per decade). Permafrost temperatures reached record high values in northernmost Alaska. A new melt extent record occurred on 11-12 July on the Greenland ice sheet; 97% of the ice sheet showed some form of melt, four times greater than the average melt for this time of year. The climate in Antarctica was relatively stable overall. The largest maximum sea ice extent since records begain in 1978 was observed in September 2012. In the stratosphere, warm air led to the second smallest ozone hole in the past two decades. Even so, the springtime ozone layer above Antarctica likely will not return to its early 1980s state until about 2060. Following a slight decline associated with the global 2 emissions from fossil fuel combustion and cement production reached a record 9.5 +/- 0.5 Pg C in 2011 and a new record of 9.7 +/- 0.5 Pg C is estimated for 2012. Atmospheric CO2 concentrations increased by 2.1 ppm in 2012, to 392.6 ppm. In spring 2012, 2 concentration exceeded 400 ppm at 7 of the 13 Arctic observation sites. Globally, other greenhouse gases including methane and nitrous oxide also continued to rise in concentration and the combined effect now represents a 32% increase in radiative forcing over a 1990 baseline. Concentrations of most ozone depleting substances continued to fall.
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  • 35
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 43 (4). pp. 805-823.
    Publication Date: 2018-04-12
    Description: Mesoscale anticyclonic eddies in the Irminger Sea are observed using a mooring and a glider. Between 2002 and 2009, the mooring observed 53 anticyclones. Using a kinematic model, objective estimates of eddy length scales and velocity structure are made for 16 eddies. Anticyclones had a mean core diameter of 12 km, and their mean peak observed azimuthal speed was 0.1 m s(-1). They had core salinities and potential temperatures of 34.91-34.98 and 4.488-5.34 degrees C, respectively, making them warm and salty features. These properties represent a typical salinity anomaly of 0.03 and a temperature anomaly of 0.28 degrees C from noneddy values. All eddies had small (〈〈 1) Rossby numbers. In 2006, the glider observed two anticyclones having diameters of about 20 km and peak azimuthal speeds of about 0.3 m s(-1). Similar salinity anomalies were detected throughout the Irminger Sea by floats profiling in anticyclones. Two formation regions for the eddies are identified: one to the west of the Reykjanes Ridge and the other off the East Greenland Irminger Current near Cape Farewell close to the mooring. Observations indicate that eddies formed in the former region are larger than eddies observed at the mooring. A clear increase in eddy salinity is observed between 2002 and 2009. The observed breakup of these eddies in winter implies that they are a source of salt for the central gyre. The anticyclones are similar to those found in both the Labrador Sea and Norwegian Sea, making them a ubiquitous feature of the subpolar North Atlantic basins.
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  • 36
    Publication Date: 2022-03-10
    Description: In this article we address the causes of the large-scale tropical sea level pressure (SLP) changes during climate change. The analysis we present is based on model simulations, observed trends and the seasonal cycle. In all three cases the regional changes of tropospheric temperature (Ttropos) and SLP are strongly related to each other (considerably stronger than (sea) surface temperature and SLP). This relationship basically follows the Bjerknes Circulation Theorem, with relatively low regional SLP where we have relatively high Ttropos and vice versa. A simple physical model suggests a tropical SLP response to horizontally inhomogeneous warming in the tropical Ttropos, with a sensitivity coefficient of about -1.7 hPa/K. This relationship explains a large fraction of observed and predicted changes in the tropical SLP. It is shown that in climate change model simulations the tropospheric land-sea warming contrast is the most significant structure in the regional Ttropos changes relative to the tropical mean changes. Since the land-sea warming contrast exists in the absent of any atmospheric circulation changes it can be argued that the large-scale response of tropical SLP changes is to first order a response to the tropical land-sea warming contrast. Further, as land-sea warming contrast is mostly available moisture dependent, the models predict a stronger warming and decreasing SLP in the drier regions from South America to Africa and a weaker warming and increasing SLP over the wetter Indo-Pacific warm pool region. This suggests an increase in the potential for deep convection conditions over the Atlantic Sector and a decrease over the Indo-Pacific warm pool region in the future.
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  • 37
    Publication Date: 2022-03-10
    Description: Variations in eastern Indian Ocean upper-ocean thermal properties are assessed for the period 1970–2004, with a particular focus on asymmetric features related to opposite phases of Indian Ocean Dipole events, using high-resolution ocean model hindcasts. Sensitivity experiments, where atmospheric forcing variability is restricted to the Indian or Pacific Ocean only, support the interpretation of forcing mechanisms for large-scale asymmetric behavior in eastern Indian Ocean variability. Years are classified according to eastern Indian Ocean subsurface heat content (HC) as proxy of thermocline variations. Years characterized by anomalous low HC feature a zonal gradient in upper-ocean properties near the equator, while high events have a meridional gradient from the tropics into the subtropics. The spatial and temporal characteristics of the seasonal evolution of HC anomalies for the two cases is distinct, as is the relative contribution from Indian Ocean atmospheric forcing versus remote influences from Pacific wind forcing: low events develop rapidly during austral winter/spring in response to Indian Ocean wind forcing associated with an enhanced southeasterly monsoon driving coastal upwelling and a shoaling thermocline in the east; in contrast, formation of anomalous high eastern Indian Ocean HC is more gradual, with anomalies earlier in the year expanding from the Indonesian Throughflow (ITF) region, initiated by remote Pacific wind forcing and transmitted through the ITF via coastal wave dynamics. Implications for seasonal predictions arise with high HC events offering extended lead times for predicting thermocline variations and upper-ocean properties across the eastern Indian Ocean.
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  • 38
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    Publication Date: 2022-03-10
    Description: European Polar Low Working Group This workshop summarized the current state of PL research in the Arctic and Antarctic. A couple of related projects are in the planning phase or already funded. The creation of a PL database for the Norwegian Sea in the frame of the Sea Surface Temperature and Altimeter Synergy (STARS) project (http://projects.met.no stars) will provide a valuable resource for future research and, potentially, predictability improvements. The maintenance of this database and the creation of similar databases for other polar areas including satellite and NWP data are highly recommended. There is also a need for free and timely access to satellite data, in particular to SAR data to fill the gap caused by the mission end of Envisat. With the increasing resolution of climate models, mesoscale processes such as polar MCs will have to be considered in international research programs such as the World Climate Research Programme (WCRP) Polar Climate Predictability Initiative and the World Weather Research Programme (WWRP) Polar Predictability Project.
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  • 39
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 42 (5). pp. 824-839.
    Publication Date: 2018-04-12
    Description: The mechanisms involved in setting the annual cycle of the Florida Current transport are revisited using an adjoint model approach. Adjoint sensitivities of the Florida Current transport to wind stress reproduce a realistic seasonal cycle with an amplitude of ~1.2 Sv (1 Sv ≡ 106 m3 s−1). The annual cycle is predominantly determined by wind stress forcing and related coastal upwelling (downwelling) north of the Florida Strait along the shelf off the North American coast. Fast barotropic waves propagate these anomalies southward and reach the Florida Strait within a month, causing an amplitude of ~1 Sv. Long baroclinic planetary Rossby waves originating from the interior are responsible for an amplitude of ~0.8 Sv but have a different phase. The sensitivities corresponding to the first baroclinic mode propagate westward and are highly influenced by topography. Considerable sensitivities are only found west of the Mid-Atlantic Ridge, with maximum values at the western shelf edge. The second baroclinic mode also has an impact on the Florida Current variability, but only when a mean flow is present. A second-mode wave train propagates southwestward from the ocean bottom on the western side of the Mid-Atlantic Ridge between ~36° and 46°N and at Flemish Cap, where the mean flow interacts with topography, to the surface. Other processes such as baroclinic waves along the shelf and local forcing within the Florida Strait are of minor importance.
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  • 40
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 42 . pp. 725-747.
    Publication Date: 2018-04-12
    Description: The residual effect of surface gravity waves on mean flows in the upper ocean is investigated using thickness weighted mean (TWM) theory applied in a vertically Lagrangian and horizontally Eulerian coordinate system. Depth-dependent equations for the conservation of volume, momentum, and energy are derived. These equations allow for (i) finite amplitude fluid motions, (ii) the horizontal divergence of currents and (iii) a concise treatment of both the kinematic and viscous boundary conditions at the sea surface. Under the assumptions of steady and monochromatic waves and a uniform turbulent viscosity, the TWM momentum equations are used to illustrate the pressure- and viscosity-induced momentum fluxes through the surface that are implicit in previous studies of the wave-induced modification of the classical Ekman spiral problem. The TWM approach clarifies, in particular, the surface momentum flux associated with the so-called virtual wave stress of Longuet-Higgins. Overall the TWM framework can be regarded as an alternative to the three-dimensional Lagrangian mean framework of Pierson. Moreover the TWM framework can be used to include the residual effect of surface waves in large-scale circulation models. In specific models that carry the TWM velocity appropriate for advecting tracers as their velocity variable, the turbulent viscosity term should be modified so that the viscosity acts only on the Eulerian mean velocity.
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  • 41
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    In:  Invertebrate Biology, 131 (2). pp. 96-109.
    Publication Date: 2016-02-24
    Description: Many aspects of barnacle body form are known to be developmentally plastic. Perhaps the most striking examples of such plasticity occur in their feeding legs and unusually long penises, the sizes and shapes of which can change dramatically and adaptively with changes in conspecific density and local water flow conditions. However, whether variation in overall appendage form is mirrored by structural responses in cuticle and muscle is not known. In order to determine how structural variation underlies phenotypic plasticity in barnacle appendages, we examined barnacles occurring at low and high population densities from one wave-protected and one wave-exposed site. We used histological sectioning and fluorescence microscopy of feeding legs and penises to compare cuticle thickness, muscle thickness, and muscle organization, and artificial penis inflation to compare penis extensibility. We observed striking differences in cuticle thickness, muscle thickness, and muscle organization between sites that differed in water velocity, but we found no clear differences associated with variation in conspecific density. Penis extensibility also did not differ consistently between sites. These results are consistent with an adaptive explanation for much of the remarkable and complex variation in barnacle feeding leg and penis morphology among sites that differ in water velocity.
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  • 42
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    In:  Journal of Climate, 25 (12). pp. 4294-4303.
    Publication Date: 2015-01-12
    Description: The tropical Atlantic wind response to El Niño forcing is robust, with weakened northeast trade winds north of the equator and strengthened southeast trade winds along and south of the equator. However, the relationship between sea surface temperature (SST) anomalies in the eastern equatorial Pacific and Atlantic is inconsistent, with El Niño events followed sometimes by warm and other times by cold boreal summer anomalies in the Atlantic cold tongue region. Using observational data and a hindcast simulation of the Nucleus for European Modeling of the Ocean (NEMO) global model at 0.5° resolution (NEMO-ORCA05), this inconsistent SST relationship is shown to be at least partly attributable to a delayed negative feedback in the tropical Atlantic that is active in years with a warm or neutral response in the eastern equatorial Atlantic. In these years, the boreal spring warming in the northern tropical Atlantic that is a typical response to El Niño is pronounced, setting up a strong meridional SST gradient. This leads to a negative wind stress curl anomaly to the north of the equator that generates downwelling Rossby waves. When these waves reach the western boundary, they are reflected into downwelling equatorial Kelvin waves that reach the cold tongue region in late boreal summer to counteract the initial cooling that is due to the boreal winter wind stress response to El Niño. In contrast, this initial cooling persists or is amplified in years in which the boreal spring northern tropical Atlantic warming is weak or absent either because of a positive North Atlantic Oscillation (NAO) phase or an early termination of the Pacific El Niño event.
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  • 43
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    In:  Journal of Climate, 25 (6). pp. 1827-1846.
    Publication Date: 2017-08-25
    Description: Initial-value predictability measures the degree to which the initial state can influence predictions. In this paper, the initial-value predictability of six atmosphere–ocean general circulation models in the North Pacific and North Atlantic is quantified and contrasted by analyzing long control integrations with time invariant external conditions. Through the application of analog and multivariate linear regression methodologies, average predictability properties are estimated for forecasts initiated from every state on the control trajectories. For basinwide measures of predictability, the influence of the initial state tends to last for roughly a decade in both basins, but this limit varies widely among the models, especially in the North Atlantic. Within each basin, predictability varies regionally by as much as a factor of 10 for a given model, and the locations of highest predictability are different for each model. Model-to-model variations in predictability are also seen in the behavior of prominent intrinsic basin modes. Predictability is primarily determined by the mean of forecast distributions rather than the spread about the mean. Horizontal propagation plays a large role in the evolution of these signals and is therefore a key factor in differentiating the predictability of the various models.
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  • 44
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    In:  Journal of the Atmospheric Sciences, 69 . pp. 1824-1840.
    Publication Date: 2018-04-16
    Description: Sudden stratospheric warmings are prominent examples of dynamical wave–mean flow interactions in the Arctic stratosphere during Northern Hemisphere winter. They are characterized by a strong temperature increase on time scales of a few days and a strongly disturbed stratospheric vortex. This work investigates a wide class of supervised learning methods with respect to their ability to classify stratospheric warmings, using temperature anomalies from the Arctic stratosphere and atmospheric forcings such as ENSO, the quasi-biennial oscillation (QBO), and the solar cycle. It is demonstrated that one representative of the supervised learning methods family, namely nonlinear neural networks, is able to reliably classify stratospheric warmings. Within this framework, one can estimate temporal onset, duration, and intensity of stratospheric warming events independently of a particular pressure level. In contrast to classification methods based on the zonal-mean zonal wind, the approach herein distinguishes major, minor, and final warmings. Instead of a binary measure, it provides continuous conditional probabilities for each warming event representing the amount of deviation from an undisturbed polar vortex. Additionally, the statistical importance of the atmospheric factors is estimated. It is shown how marginalized probability distributions can give insights into the interrelationships between external factors. This approach is applied to 40-yr and interim ECMWF (ERA-40/ERA-Interim) and NCEP–NCAR reanalysis data for the period from 1958 through 2010.
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  • 45
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    In:  Journal of Climate, 25 (1). pp. 184-206.
    Publication Date: 2017-08-24
    Description: To analyze the probability density distributions of surface turbulent heat fluxes, the authors apply the twoparametric modified Fisher–Tippett (MFT) distribution to the sensible and latent turbulent heat fluxes recomputed from 6-hourly NCEP–NCAR reanalysis state variables for the period from 1948 to 2008. They derived the mean climatology and seasonal cycle of the location and scale parameters of the MFT distribution. Analysis of the parameters of probability distributions identified the areas where similar surface turbulent fluxes are determined by the very different shape of probability density functions. Estimated extreme turbulent heat fluxes amount to 1500–2000 W m22 (for the 99th percentile) and can exceed 2000 W m22 for higher percentiles in the subpolar latitudes and western boundary current regions. Analysis of linear trends and interannual variability in the mean and extreme fluxes shows that the strongest trends in extreme fluxes (more than 15 W m22 decade21) in the western boundary current regions are associated with the changes in the shape of distribution. In many regions changes in extreme fluxes may be different from those for the mean fluxes at interannual and decadal time scales. The correlation between interannual variability of themean and extreme fluxes is relatively low in the tropics, the SouthernOcean, and the Kuroshio Extension region.Analysis of probability distributions in turbulent fluxes has also been used in assessing the impact of sampling errors in theVoluntaryObserving Ship (VOS)-based surface flux climatologies, allowed for the estimation of the impact of sampling in extreme fluxes. Although sampling does not have a visible systematic effect onmean fluxes, sampling uncertainties result in the underestimation of extreme flux values exceeding 100 W m22 in poorly sampled regions.
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  • 46
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    AMS (American Meteorological Society)
    In:  Journal of Climate, 25 (1). pp. 207-221.
    Publication Date: 2014-10-21
    Description: Antarctic Intermediate Water (AAIW) is a dominant Southern Hemisphere water mass that spreads from its formation regions just north of the Antarctic Circumpolar Current (ACC) to at least 20°S in all oceans. This study uses an isopycnal climatology constructed from Argo conductivity–temperature–depth (CTD) profile data to define the current state of the AAIW salinity minimum (its core) and thence compute anomalies of AAIW core pressure, potential temperature, salinity, and potential density since the mid-1970s from ship-based CTD profiles. The results are used to calculate maps of temporal property trends at the AAIW core, where statistically significant strong circumpolar shoaling (30–50 dbar decade−1), warming (0.05°–0.15°C decade−1), and density reductions [up to −0.03 (kg m−3) decade−1] are found. These trends are strongest just north of the ACC in the southeast Pacific and Atlantic Oceans and decrease equatorward. Salinity trends are generally small, with their sign varying regionally. Bottle data are used to extend the AAIW core potential temperature anomaly analysis back to 1925 in the Atlantic and to ~1960 elsewhere. The modern warm AAIW core conditions appear largely unprecedented in the historical record: biennially and zonally binned median AAIW core potential temperatures within each ocean basin are, with the notable exception of the subtropical South Atlantic in the 1950s–70s, 0.2–1°C colder than modern values. Zonally averaged sea surface temperature anomalies around the AAIW formation latitudes in each ocean and sectoral southern annular mode indices are used to put the AAIW core property trends and variations into context.
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  • 47
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    AMS (American Meteorological Society)
    In:  Bulletin of the American Meteorological Society, 93 (7). S1-S282.
    Publication Date: 2019-07-09
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  • 48
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    In:  Weather, Climate, and Society, 4 (3). pp. 212-229.
    Publication Date: 2021-03-30
    Description: Anthropogenic emissions of greenhouse gases could lead to undesirable effects on oceans in coming centuries. Drawing on recommendations published by the German Advisory Council on Global Change, levels of unacceptable global marine change (so-called guardrails) are defined in terms of global mean temperature, sea level rise, and ocean acidification. A global-mean climate model [the Aggregated Carbon Cycle, Atmospheric Chemistry and Climate Model (ACC2)] is coupled with an economic module [taken from the Dynamic Integrated Climate–Economy Model (DICE)] to conduct a cost-effectiveness analysis to derive CO2 emission pathways that both minimize abatement costs and are compatible with these guardrails. Additionally, the “tolerable windows approach” is used to calculate a range of CO2 emissions paths that obey the guardrails as well as a restriction on mitigation rate. Prospects of meeting the global mean temperature change guardrail (2° and 0.2°C decade−1 relative to preindustrial) depend strongly on assumed values for climate sensitivity: at climate sensitivities 〉3°C the guardrail cannot be attained under any CO2 emissions reduction strategy without mitigation of non-CO2 greenhouse gases. The ocean acidification guardrail (0.2 unit pH decline relative to preindustrial) is less restrictive than the absolute temperature guardrail at climate sensitivities 〉2.5°C but becomes more constraining at lower climate sensitivities. The sea level rise and rate of rise guardrails (1 m and 5 cm decade−1) are substantially less stringent for ice sheet sensitivities derived in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report, but they may already be committed to violation if ice sheet sensitivities consistent with semiempirical sea level rise projections are assumed.
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  • 49
    Publication Date: 2022-03-10
    Description: Historical hydrographic data (1940s–2010) show a distinct cross-slope difference of the lower halocline water (LHW) over the Laptev Sea continental margins. Over the slope, the LHW is on average warmer and saltier by 0.2°C and 0.5 psu, respectively, relative to the off-slope LHW. The LHW temperature time series constructed from the on-slope historical records are related to the temperature of the Atlantic Water (AW) boundary current transporting warm water from the North Atlantic Ocean. In contrast, the on-slope LHW salinity is linked to the sea ice and wind forcing over the potential upstream source region in the Barents and northern Kara Seas, as also indicated by hydrodynamic model results. Over the Laptev Sea continental margin, saltier LHW favors weaker salinity stratification that, in turn, contributes to enhanced vertical mixing with underlying AW.
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  • 50
  • 51
    Publication Date: 2023-11-08
    Description: The equatorial deep jets (EDJ) are a striking feature of the equatorial ocean circulation. In the Atlantic Ocean, the EDJ are associated with a vertical scale of between 300 and 700 m, a time scale of roughly 4.5 years and upward energy propagation to the surface. It has been found that the meridional width of the EDJ is roughly 1.5 times larger than expected based on their vertical scale. Here we use a shallow water model for a high order baroclinic vertical normal mode to argue that mixing of momentum along isopycnals can explain the enhanced width. A lateral eddy viscosity of 300 m2 s−1 10 is found to be sufficient to account for the width implied by observations.
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  • 52
    Publication Date: 2021-03-29
    Description: This proceeding volume results from the submitted abstracts of the international symposium “The Stability of Rainforest Margins: Linking Ecological, Economic and Social Constraints” held on September 19 – 23, 2005 in Göttingen, Germany. Tropical rainforests disappear at an alarming rate causing unprecedented losses in biodiversity and ecosystem services. Rainforests are hot spots of biodiversity as well as important carbon sinks. Despite an increased recognition of the value of these and other valuable public goods provided by tropical rainforests at national and international levels, the rainforests of Asia, Africa, Australia and Latin America continue to be seriously threatened by various forms of human encroachment. The analysis of policies and socio-economic and ecological determinants that either stabilize or threaten tropical forest margins requires a holistic interdisciplinary scientific approach. Such an approach has been adopted by a large scale research program titled “Stability of Rainforest Margins in Indonesia” (www.storma.de). This research program started in 2000 and is jointly conducted by the two German Universities, the Georg-August-University of Göttingen (GAUG) and the University of Kassel (UNIK), and by two Indonesian Universities, the Agricultural University of Bogor (Institut Pertanian Bogor, IPB) and the Tadulako University (UNTAD) in Palu. Referring to the main research foci of STORMA, the symposium features three interconnected thematic foci of interdisciplinary research. They refer to changes in the extent and intensity of agricultural and forest land use in tropical forest margins and their implications for rural development and for conservation of natural resources such as biodiversity, soils and water. The first focus “Integrated spatial modeling of land use in tropical forest margins” concerns rain forest margins around the world which comprise a variety of landuse systems, with forest gardens, annual crops in slash-and-burn and agroforestry systems, as well as intensive cultivation, mostly in the valleys. An understanding of the dynamics of land-use change and related resource degradation under various policies scenarios is required, and strategies to reduce and potentially reverse degradation processes are to be developed. The second focus “Sustainable management of agroforestry systems” concerns lowintensity agroforestry which may support high biodiversity stabilizing ecosystem functioning, in particular when shaded by natural trees and neighboured by natural forest. In contrast, high-intensity agroforestry with planted shade trees and in an agricultural landscape context may be characterized by less environmental benefits and high agrochemical inputs. In this focus, the ecological and socio-economic benefits of different management practices will be compared and related to patterns and processes in natural forests. The third focus “Ecological and socio-economic impacts of different forest-use intensities” analyzes ecological and socio-economic benefits and costs across different types of forest use. The consequences of low- and medium-intensity forest-use practices, such as selective timber and rattan extraction, for biodiversity and ecosystem functioning are assessed. We are grateful to our sponsors, namely the German Research Council (DFG), the Georg-August-University Göttingen and the University of Kassel. Our special Thanks goes to the Universities Institut Pertanian Bogor (IPB) and Tadulako University (UNTAD) in Palu for their cooperation in the Collaborative Research Centre (SFB 552) “Stability of Rainforest Margins in Indonesia” (STORMA).
    Description: conference
    Keywords: 333.7 ; QEL 000 ; QG 380 ; UBA 700 ; UBO 600 ; VOI 210 ; QFC 210 ; QFC 200 ; QFC 450 ; QFC 445 ; human activity ; tropical environment ; rain forests ; land-use ; natural resources ; water balance ; pollution ; ecosystems ; biodiversity ; symposia ; meeting ; 38.09
    Language: English
    Type: anthology
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  • 53
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    In:  Journal of Climate, 24 (14). pp. 3345-3557.
    Publication Date: 2019-09-23
    Description: The suggestion is advanced that the remarkably low static stability of Antarctic surface waters may arise from a feedback loop involving global deep-water temperatures. If deep-water temperatures are too warm, this promotes Antarctic convection, thereby strengthening the inflow of Antarctic Bottom Water into the ocean interior and cooling the deep ocean. If deep waters are too cold, this promotes Antarctic stratification allowing the deep ocean to warm because of the input of North Atlantic Deep Water. A steady-state deep-water temperature is achieved such that the Antarctic surface can barely undergo convection. A two-box model is used to illustrate this feedback loop in its simplest expression and to develop basic concepts, such as the bounds on the operation of this loop. The model illustrates the possible dominating influence of Antarctic upwelling rate and Antarctic freshwater balance on global deep-water temperatures.
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  • 54
    Publication Date: 2020-08-14
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  • 55
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    In:  Bulletin of the American Meteorological Society, 92 (5). pp. 637-640.
    Publication Date: 2019-09-23
    Description: The importance of decadal climate variability (DCV) research is being increasingly recognized, including by the World Climate Research Program (WCRP) and the Intergovernmental Panel on Climate Change (IPCC). An improved understanding of DCV is very important because stakeholders and policymakers want to know the likely climate trajectory for the coming decades for applications to water resources, agriculture, energy, and infrastructure development. Responding to this demand, many climate modeling groups in the United States, Europe, Japan, and elsewhere are gearing up to assess the potential for decadal climate predictions. The magnitudes of regional DCV often exceed those associated with the trends resulting from anthropogenic changes. Therefore, differentiating between the two is also very important for planning, implementation, and national and international treaties.
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  • 56
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    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 41 (11). pp. 2242-2258.
    Publication Date: 2018-04-12
    Description: Simple idealized layered models and primitive equation models show that the meridional gradient of the zonally averaged pressure has no direct relation with the meridional flow. This demonstrates a contradiction in an often-used parameterization in zonally averaged models. The failure of this parameterization reflects the inconsistency between the model of Stommel and Arons and the box model of Stommel, as previously pointed out by Straub. A new closure is proposed. The ocean is divided in two dynamically different regimes: a narrow western boundary layer and an interior ocean; zonally averaged quantities over these regions are considered. In the averaged equations three unknowns appear: the interior zonal pressure difference Delta p(i), the zonal pressure difference Delta p(b) of the boundary layer, and the zonal velocity us at the interface between the two regions. Here Delta p(i) is parameterized using a frictionless vorticity balance, Delta p(b), by the difference of the mean pressure in the interior and western boundary, and u(delta) by the mean zonal velocity of the western boundary layer. Zonally resolved models, a layer model, and a primitive equation model validate the new parameterization by comparing with the respective zonally averaged counterparts. It turns out that the zonally averaged models reproduce well the buoyancy distribution and the meridional flow in the zonally resolved model versions with respect to the mean and time changes.
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  • 57
    Publication Date: 2017-08-24
    Description: Continuous estimates of the oceanic meridional heat transport in the Atlantic are derived from the Rapid Climate Change–Meridional Overturning Circulation (MOC) and Heatflux Array (RAPID–MOCHA) observing system deployed along 26.5°N, for the period from April 2004 to October 2007. The basinwide meridional heat transport (MHT) is derived by combining temperature transports (relative to a common reference) from 1) the Gulf Stream in the Straits of Florida; 2) the western boundary region offshore of Abaco, Bahamas; 3) the Ekman layer [derived from Quick Scatterometer (QuikSCAT) wind stresses]; and 4) the interior ocean monitored by “endpoint” dynamic height moorings. The interior eddy heat transport arising from spatial covariance of the velocity and temperature fields is estimated independently from repeat hydrographic and expendable bathythermograph (XBT) sections and can also be approximated by the array. The results for the 3.5 yr of data thus far available show a mean MHT of 1.33 ± 0.40 PW for 10-day-averaged estimates, on which time scale a basinwide mass balance can be reasonably assumed. The associated MOC strength and variability is 18.5 ± 4.9 Sv (1 Sv ≡ 106 m3 s−1). The continuous heat transport estimates range from a minimum of 0.2 to a maximum of 2.5 PW, with approximately half of the variance caused by Ekman transport changes and half caused by changes in the geostrophic circulation. The data suggest a seasonal cycle of the MHT with a maximum in summer (July–September) and minimum in late winter (March–April), with an annual range of 0.6 PW. A breakdown of the MHT into “overturning” and “gyre” components shows that the overturning component carries 88% of the total heat transport. The overall uncertainty of the annual mean MHT for the 3.5-yr record is 0.14 PW or about 10% of the mean value.
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  • 58
    Publication Date: 2019-09-23
    Description: The water mass structure of the Arctic Ocean is remarkable, for its intermediate (depth range ~150–900 m) layer is filled with warm (temperature 〉0°C) and salty water of Atlantic origin (usually called the Atlantic Water, AW). This water is carried into and through the Arctic Ocean by the pan-Arctic boundary current, which moves cyclonically along the basins’ margins (Fig. 1). This system provides the largest input of water, heat, and salt into the Arctic Ocean; the total quantity of heat is substantial, enough to melt the Arctic sea ice cover several times over. By utilizing an extensive archive of recently collected observational data, this study provides a cohesive picture of recent large-scale changes in the AW layer of the Arctic Ocean. These recent observations show the warm pulse of AW that entered the Arctic Ocean in the early 1990s finally reached the Canada Basin during the 2000s. The second warm pulse that entered the Arctic Ocean in the mid-2000s has moved through the Eurasian Basin and is en route downstream. One of the most intriguing results of these observations is the realization of the possibility of uptake of anomalous AW heat by overlying layers, with possible implications for an already-reduced Arctic ice cover.
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  • 59
    Publication Date: 2022-03-10
    Description: Vertical mixing in the bottom boundary layer and pycnocline of the Laptev Sea is evaluated from a rapidly sampled 12-h time series of microstructure temperature, conductivity, and shear observations collected under 100% sea ice during October 2008. The bottom boundary turbulent kinetic energy dissipation was observed to be enhanced (ϵ ∼ 10−4 W m−3) beyond background levels (ϵ ∼ 10−6 W m−3), extending up to 10 m above the seabed when simulated tidal currents were directed on slope. Upward heat fluxes into the halocline-class waters along the Laptev Sea seabed peaked at ∼4–8 W m−2, averaging out to ∼2 W m−2 over the 12-h sampling period. In the Laptev Sea pycnocline, an isolated 2-h episode of intense dissipation (ϵ ∼ 10−3 W m−3) and vertical diffusivities was observed that was not due to a localized wind event. Observations from an acoustic Doppler current meter moored in the central Laptev Sea near the M2 critical latitude are consistent with a previous model in which mixing episodes are driven by an enhancement of the pycnocline shear resulting from the alignment of the rotating pycnocline shear vector with the under-ice stress vector. Upward cross-pycnocline heat fluxes from the Arctic halocline peaked at ∼54 W m−2, resulting in a 12-h average of ∼12 W m−2. These results highlight the intermittent nature of Arctic shelf sea mixing processes and how these processes can impact the transformation of Arctic Ocean water masses. The observations also clearly demonstrate that absence or presence of sea ice profoundly affects the availability of near-inertial kinetic energy to drive vertical mixing on the Arctic shelves.
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  • 60
    Publication Date: 2021-03-29
    Description: Die Västervik Region liegt an einer Haupt-Terran-Grenze im Baltischen Schild. Im NE schließen sich die Einheiten des Südsvecofennischen Vulkanitgürtels mit Altern 〉1,85Ga an, im SW folgen die Granitoide des Transskandinavischen Magmatitgürtles (TMZ) mit Altern 〈1,85Ga. Die Metasedimente der Västervik Formation bilden die stratigraphisch älteste Einheit der Västervik Region. Ihre Stellung in Bezug auf die svecofennischen Metasedimente des Bothnischen Beckens ist noch unklar. Sie können nach ihren mineralogischen Paragenesen in vier Gruppen klassifiziert werden: reine Quarzite, glimmerführende Quarzite, Glimmerquarzite und quarzitische Gneise. Vermutlich zeitgleich mit der Intrusion der großvolumigen Granitoidmagmen ab 1.85 Ga wurde die Västervik Formation amphibolitfaziell überprägt. Dies führte innerhalb der Metasedimente zur Bildung von Cordierit, Sillimanit und Andalusit sowie akzessorischem Granat. Der Beginn der Sedimentation ist begrenzt durch das Vorkommen detritischer Zirkone mit Altern ab 1.87Ga. Etwa 75% der gemessenen detritische Zirkone zeigt eine Altersgruppierung von 1,8 bis 2,1 Ga, die restlichen 25% zeigen archaische U/Pb-Alter von 2,8 bis 3,0 Ga (Claesson et al. 1993, Sultan et al. 2005). Die Nd-Isotopensignaturen der Proben zeigen eine sehr homogene Mischung und Schüttung der Sedimente mit subparallelem Verlauf der Nd- Entwicklungslinien und einem sehr engen TDM (Nd) Altersspektrum von 2,2 bis 2,4Ga. Diese Ergebnisse deuten auf ein konstantes Mischungsverhältnis von proterozoischen und archaischen Anteilen hin...
    Description: conference
    Keywords: 551 ; VBO 000 ; VBN 500 ; VKB 292 ; VKB 250 ; VJJ 110 ; VJB 312 ; VED 200 ; VEG 110 ; Isotopengeologie ; Geochronologie einzelner Regionen im allgemeinen ; Metamorphe Komplexe, übriges Europa {Petrologie} ; Metasedimente {Petrologie} ; Geochemie der Stabilen Isotopen ; Geochemie der Metamorphite ; Schweden {Geologie} ; Europäische Plattform {Geologie} ; Svekofenniden ; Västervik 〈Region〉 ; Proterozoikum ; Metasediment ; Samarium ; Neodym ; Isotopengeochemie
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 61
    Publication Date: 2021-03-29
    Description: The synformal geometry of the 1.85Ga Sudbury Igneous Complex (SIC), an impact melt sheet resulting from largemagnitude meteorite impact, attests to post-impact deformation. However, in contrast to the overlying Onaping Formation, a heterolithic impact melt breccia, the SIC shows little evidence for pervasive ductile strain. This pertains in particular to its NE-lobe characterized by a curvature of about 100° in plain view. This curvature has been interpreted either as a fold or as a primary feature. In order to test these scenarios, a detailed structural analysis was conducted in the core of the NE-lobe, which consists of rocks of the Onaping Formation...
    Description: conference
    Keywords: 551 ; VKB 280 ; VKB 295 ; VAE 140 ; VEV 127 ; VKA 200 ; Impaktgesteine {Petrologie} ; Metamorphe Komplexe, Nordamerika {Petrologie} ; Gesteinsdeformation {Strukturgeologie} ; Ontario {Geologie} ; Gefügekunde der Gesteine ; Sudbury 〈Ontario. Region〉 ; Mehrfachringbassin ; Proterozoikum ; Impaktmetamorphes Gestein ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 62
    Publication Date: 2021-03-29
    Description: Seit dem Mesozoikum wächst die kontinentale Kruste am aktiven Plattenrand von Kamtschatka durch Akkretion allochthoner Terrane. Dieses Wachstum manifestiert sich in der differenziellen Exhumierung und Hebung tektonischer Blöcke innerhalb des Akkretionskeils, parallel zum Kamtschatka- Graben. Die Kinematik der Exhumierung soll mittels strukturgeologischer und neotektonischer Deformationsanalyse erfasst und mit thermochronologischen Untersuchungen an Apatiten bis etwa ins Untere Pliozän quantifiziert werden.
    Description: conference
    Keywords: 551 ; VAE 880 ; VAE 400 ; VBN 500 ; VEG 190 ; Passive und aktive Kontinentalränder {Geologie} ; Tektogenese {Geologie} ; Geochronologie einzelner Regionen im allgemeinen ; Koriakia-Kamtchatkasystem {Geologie} ; Kamtschatka 〈Oblast〉 ; Kontinentalrand ; Deformation 〈Geologie〉 ; Hebung 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 63
    Publication Date: 2021-03-29
    Description: Die Grenze zwischen zwei ophiolithischen Decken der penninischen Alpen, der Zermatt-Saas-Zone (unten) und der Combinzone (oben), markiert zugleich einen bedeutenden Sprung der bei der tertiären alpinen Metamorphose maximal erreichten Drücke. Während die Zermatt-Saas-Zone Ultrahochdruckmetamorphose (25–30 kbar/550–600°C, Bucher et al. 2005) erfuhr, erreichte die Combinzone lediglich blauschieferfazielle Bedingungen (13–18 kbar/380– 550°C, Bousquet et al. 2004). Vor allem die Polarität des Drucksprunges führte dazu, daß die Deckengrenze zumeist als gewaltige südostvergente Abschiebung interpretiert wurde (z.B. Ballèvre & Merle 1993, Reddy et al. 1999). Strukturgeologische Geländebeobachtungen ergeben jedoch sowohl für das Hangende als auch das Liegende der Combinstörung die folgende kinematische Entwicklung: i) Nordwestvergente, überschiebende Scherung (D1), ii) (Süd)westvergente Scherung (D2),iii) Südostvergente, abschiebende Scherung (D3). Alle drei Deformationsphasen fanden in beiden Einheiten unter grünschieferfaziellen Bedingungen statt... Die Rekonstruktion ergibt, daß die Combinstörung hauptsächlich als Überschiebung aktiv war. Die Exhumierung der Gesteinseinheiten im Liegenden wurde nicht durch Extension, sondern durch vertikale Ausdünnung der Kruste während horizontaler Kontraktion bewirkt.
    Description: conference
    Keywords: 551 ; VAE 811 ; VAE 400 ; VEB 168 ; VAE 140 ; Alpidische Orogene {Geologie} ; Tektogenese {Geologie} ; Schweizer Alpen {Geologie} ; Gesteinsdeformation {Strukturgeologie} ; Penninikum ; Tektonische Decke ; Scherzone ; Deformation 〈Geologie〉 ; Hebung 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 64
    facet.materialart.
    Unknown
    Universitätsverlag Göttingen
    Publication Date: 2021-03-29
    Description: Analytical modelling of geological fractures is now at an exciting stage. In view of the ever-mounting amount of fracture data available, and the need for a European overview of the state of the art, we correlate fractures from across the continent. In order to achieve relevant and meaningful statistics, the dataset of millions of entries was downsampled to filter out inadequate and irrelevant values. The resulting data are the object of this study...
    Description: conference
    Keywords: 551 ; VEA 000 ; VAE 150 ; VAE 830 ; Europa insgesamt {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Bruchschollenstrukturen {Geologie} ; Europa ; Bruchtektonik
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 65
    Publication Date: 2021-03-29
    Description: Piton de la Fournaise (Réunion Island) is an active basaltic shield volcano in the south-western part of the Indian Ocean. The activity consists essentially of lava being issued from two rift zones close to the summit cone. The summit cone has been monitored since 1980 by the OVPF (Volcanological Observatory of Piton de la Fournaise). Geodetic data and radar interferometry show a systematic asymmetric pattern of deformation associated with all the N–S trending eruptive fissures (Briole et al. 1998, Sigmundsson et al. 1999). The asymmetric deformation has been interpreted in various ways. The two main models proposed are (1) eastward dip of the dykes, based on inversion of data provided by radar interferometry (Sigmundsson et al 1999), and (2) the existence of a free boundary in the east part of the volcano. The second model allows the accommodation of dykes by eastward displacements, whilst the western part of the volcano is supported by the existing Piton des Neiges (Lénat et al., 1989). However,no displacements occur along the eastern coastline of Piton de la Fournaise. The only parts of the volcano affected by deformation are the rift zones and the summit cone. Moreover, geodetic data provided by the new real-time GPS network show that there is an asymmetric deformation of the summit cone prior to eruption (Staudacher 2005). The deformation itself seems to be related to pressure increase in the magma chamber. Absence of permanent displacements during periods of rest (such as 1992–1998) (Briole et al. 1998) support this link between magmatic pressure and deformation. Here we complement previous deformation studies by the results of several numerical models that aim at understanding the internal processes resulting in deformation of the volcano...
    Description: conference
    Keywords: 551 ; VAD 700 ; VAD 300 ; VAE 200 ; VEZ 200 ; Regionaler Vulkanismus {Geologie} ; Vulkanformen und Vulkantypen {Geologie} ; Geodynamik der Lithosphäre {Geologie} ; Indischer Ozean {Geologie} ; Piton de la Fournaise ; Schildvulkan ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 66
    Publication Date: 2021-03-29
    Description: Impact of solid bodies is the most fundamental of all processes that have taken place on the terrestrial planets in our Solar system (Shoemaker 1977). On Earth, impact cratering was the dominant geologic process during the period of the early heavy bombardment until 3.8Ga. A constant asteroid impact flux exists since that time. Although deformation of the crust by meteorite impacts is now subordinate with respect to tectonics, it represents an important, but often underestimated fraction of the bulk crustal deformation. Short-term deformation during hypervelocity impact events differs in many respects from standard tectonics: Unique conditions exist at pressures above the so-called Hugoniot elastic limit (HEL) of a particular mineral or rock. This state of compression is reached in a shock wave that propagates from the point of impact. Shock waves travel at supersonic velocity, heat and irreversibly deform the rock, and cause a residual motion of the material they have passed, which ultimately leads to the formation of parabolically shaped crater cavity of much larger extent than the projectile diameter. At pressure above the HEL minerals are subjected to shock metamorphism...
    Description: conference
    Keywords: 551 ; VKB 280 ; Impaktgesteine {Petrologie} ; Sandstein ; Impaktmetamorphose
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 67
    Publication Date: 2021-03-29
    Description: Microscopic study is an indispensable step in the determination of the petrographic characteristics of rocks. In Cameroon just like in most developing countries, simple polarizing microscopes of the 20th Century constitute the only available material for macroscopic studies. A major difficulty encountered in the use of these instruments resides in the realisation of photographs of the different parts of the thin section that require illustrations. The technique that has been used upto now has been inefficient and unsatisfactory. Faced with this recurrent situation, we thought of setting up a new, semi-modern, practical and very economical technique for photographing the thin section.
    Description: conference
    Keywords: 551 ; VAE 120 ; VGB 400 ; VKA 130 ; Methodik {Strukturgeologie} ; Optische Bestimmungsmethoden {Mineralogie} ; Optische Petrographie ; Dünnschliffmikroskopie ; Mikrofotographie
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 68
    Publication Date: 2021-03-29
    Description: Intense seismicity and intensely developed active and ancient fault systems are common to the Aegean Region. Extending/ thinning crust involves a complex interplay of (1) Gulf of Corinth riftexpansion, (2) west- and south-ward retreat of the Hellenic Trench, (3) westward impingement of the Anatolian Platen, and/or (4) propagation of the Anatolian Fault system into the Aegean. New geological/structural investigations on Kea (also known as Tzia), in the Western Cyclades reveal a low angle crustal-scale, detachment-type ductile shear zone probably formed during Miocene extension and thinning of the continental crust...
    Description: conference
    Keywords: 551 ; VEF 300 ; VAE 130 ; VKB 270 ; VAE 400 ; Griechenland und griechische Inseln {Geologie} ; Geomechanik ; Produkte mechanischer Deformation {Petrologie} ; Tektogenese {Geologie} ; Kea ; Erdkruste ; Extension 〈Geologie〉 ; Scherzone
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 69
    facet.materialart.
    Unknown
    Universitätsverlag Göttingen
    Publication Date: 2021-03-29
    Description: Gruppen von parallel einfallenden Abschiebungen treten in der Natur sehr häufig und in unterschiedlichsten Dimensionen auf. Existierende, überwiegend experimentelle Arbeiten führen einheitliches Einfallen auf laterale Festigkeitsschwankungen oder, vor allem, auf horizontale Scherspannungen zurück (e.g. Brun et al. 1994, Behn et al. 2002). Einheitliche horizontale Scherspannungen im großen Maßstab werden mit einer konsistenten Fließrichtung in der mittleren und/oder unteren Kruste erklärt. Beobachtungen in einigen der bedeutensten Rift-Systeme lassen jedoch beide Erklärungen als zentrale Ursache unwahrscheinlich erscheinen. In der Basin-and-Range-Provinz in den westlichen Vereinigten Staaten ändert sich die Einfallrichtung von parallelen Abschiebungen im Streichen der Störungen, so dass strukturelle Domänen mit intern einheitlicher Einfallrichtung entstehen, die von Blattverschiebungen untereinander getrennt werden. Eine solche Geometrie ließe sich nur mit bizarren Fließmustern in der Unterkruste erklären. Wir präsentieren numerische Extensionsexperimente von sprödem Material, das auf einem linear-viskosen Substrat ruht... In unseren Modell sind parallele Abschiebungen nicht, wie bisher angenommen, auf einheitlichen horizontalen Scherstress, sondern auf vertikale Normalspannungen zurückzuführen, d.h. auf den Widerstand, den das viskose Substrat vertikalen Blockbewegungen in der spröden Lage entgegensetzt. Wenn unser Modell richtig ist, würde das für Gebiete wie die Basin-and- Range-Provinz bedeuten, dass die spröde Oberkruste auf einer wenige Kilometer dicken, viskosen mittleren Kruste liegt, die wiederum ein festeres Substrat hat. Die Unterkruste müsste deutlich fester sein als die mittlere Kruste. Es scheint, dass Folgen von parallelen Abschiebungen häufig in dünnen, niedrig viskosen Lagen (etwa Ton oder Salz) wurzeln.
    Description: conference
    Keywords: 551 ; VAE 830 ; VAE 130 ; VAE 120 ; VBE 000 ; Bruchschollenstrukturen {Geologie} ; Geomechanik ; Methodik {Strukturgeologie} ; Modellierung von Prozessen in der Geosphäre ; Bruchscholle ; Abschiebung 〈Geologie〉 ; Geomechanik ; Numerisches Modell
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 70
    Publication Date: 2021-03-29
    Description: There is substantial need in mineral exploration to understand the structural controls on ore deposition for these types of deposits in order to predict the localities of new ones. Application of basic principles of rock mechanics, and numerical simulations of deformation and fluid flow processes provide fundamental insights to Proterozoic hydrothermal mineralization atMount Isa, Australia. The rheology of layered meta-sedimentary rocks, and the orientation and position of these layered rocks relative to major fault systems were the key controls on ore deposition...
    Description: conference
    Keywords: 551 ; VQB 000 ; VQD 200 ; VRA 300 ; VTS 400 ; VQC 000 ; Tektonik von Lagerstätten ; Metamorphe Lagerstätten ; Buntmetalle {Lagerstättenkunde} ; Queensland {Rohstoffgeologie} ; Lagerstättengenese ; Mount-Isa-Gebiet ; Hydrothermale Erzlagerstätte ; Geodynamik ; Metallogenese
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 71
    Publication Date: 2021-03-29
    Description: Most asteroids strike their target at an oblique angle (Pierazzo & Melosh 2000). The common criterion for identifying craters formed by an oblique impact is the pattern of the ejecta blanket. On Earth, however, ejecta blankets are rarely preserved and morphological, structural, geophysical as well as depositional criteria were used to infer an oblique impact (e.g. for Chicxulub, Schultz & D’Hondt 1996, Ries- Steinheim, Stöffler et al. 2003, Mjölnir & Tsikalas 2005). However, the significance of such criteria in predicting impact angle or direction is a matter of debate (c.f. Schultz & Anderson, 1996, Ekholm & Melosh 2001). Particularly, it is not yet known whether there is an influence of the impact angle on the displacement field during the collapse of large transient cavities, and thus, the final crater. For most impact angles, the shape of the final crater is controlled by its size. At a critical diameter (ca. 2–5 km on Earth), simple bowl shaped craters are getting gravitationally unstable and collapse to form complex craters, with a flat floor and a terraced rim (Melosh 1989). During collapse, the crater floor rises to form a central uplift, that may or may not be visible as a central peak, or, when the peak in turn collapses, as a peak ring at yet larger diameters.
    Description: conference
    Keywords: 551 ; VAE 150 ; VAX 000 ; VEV 277 ; Strukturelle Erscheinungen {Strukturgeologie} ; Akkretion extraterrestrischen Materials {Geologie} ; Utah {Geologie} ; Utah 〈Südost〉 ; Impaktstruktur ; Strukturgeologie
    Language: German
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  • 72
    Publication Date: 2021-03-29
    Description: The 1.85 Ga Sudbury Igneous Complex (SIC) in central Ontario is now widely considered to be the erosional remnant of a deformed paleo-horizontal impact melt sheet, about 2.5 km in thickness. Deformed impact melt breccias of the Onaping Formation and postimpact metasedimentary rocks overlie the layered SIC, which in turn rests on shocked Archean basement and Paleoproterozoic cover rocks. The main mass of the Igneous Complex is subdivided from top to bottom into granophyre, quartz-gabbro and norite layers. Previous workers considered noncylindrical folding and NW-directed reverse faulting as the main structural processes that formed the asymmetric, syn-formal geometry of the SIC apparent in map view and seismic section. Structural studies support this model in the southern part of the impact structure, where greenschist-facies metamorphic tectonites of the South Range Shear Zone (SRSZ) accomplished structural uplift of the southern SIC by NW-directed reverse shearing. However, little evidence for pervasive ductile strain has been reported from the weakly metamorphosed eastern part of the SIC, the East Range, which is characterised by steep basal dips and maximal curvature in plan view. The objective of this study is to assess the structural inventory of the East Range in terms of post-emplacement deformation mechanisms. Our interpretation is based on published and newly acquired structural data. Planar mineral shape fabrics of cumulate plagioclase and pyroxene are developed in the intermediate quartz-gabbro and lower norite layers of the southern East Range SIC. Microstructures show little intracrystalline deformation in quartz. Euhedral cumulate plagioclase retains an angular outline indicating magmatic mineral fabric development. This magmatic foliation is concordant to SIC contacts or large-scale discontinuities in their vicinity (Fig. 1). Magmatic fabrics are observed rarely in the northern portion of the East Range. Here, tectonic foliations and S–C fabrics are developed sporadically at, and concordant to, brittle structures striking N–S. A weak tectonic foliation defined by chlorite that replaces magmatic minerals is developed in the upper granophyric SIC of the NE-lobe that connects the SIC’s North and East Ranges via a 105° arc. This foliation grades into a shape-preferred orientation of primary, i.e., magmatic, mafic minerals observed in the lower granophyre and underlying layers of the SIC. Mineral fabrics observed in the NE-lobe SIC are concordant to metamorphic foliations developed in the overlying Onaping Formation breccias. Both foliations strike parallel to the NE-Lobe’s acute bisectrix and, thus, display an axial-planar geometry typical for fabrics formed in the core of a buckle fold (Fig. 1). Brittle structures including centimetre-scale shear-fractures to kilometre-scale faultzones are observed in the eastern SIC and its host rocks. Largescale faults striking N–S cut the NElobe’s eastern limb causing variable magnitudes of strike separation of SIC contacts. Centimetre- to metrescale, brittle faults and chlorite-filled brittle-ductile shear-zones occur pervasively in the eastern SIC, often causing centimetre-scale offset of markers. Microstructures from first-order fault-zones indicate deformation at, and below, greenschist-facies metamorphic conditions. The concordance of magmatic and tectonic mineral shape fabrics in the NElobe indicates progressive deformation of the SIC during cooling from the magmatic state to lower greenschistfacies metamorphic conditions. Synmagmatic deformation of the SIC suggests that it was emplaced during ongoing orogenic deformation. Furthermore, maximum principal stress directions inferred from inversion of faultslip data collected in the Onaping Formation are orthogonal to metamorphic foliation surfaces at the same localities. This points to a similar deformation regime in the Onaping Formation during ductile and brittle deformation. The concordance of magmatic, metamorphic and brittle fabrics is explained best by a single progressive deformation event that was active while the SIC cooled and solidified. The lack of pervasive ductile deformation fabrics in the East Range SIC can be explained by rapid cooling of the impact melt sheet (within 100–500 ka) with respect to natural tectonic strain rates. While the geometry of mineral fabrics in the study area is compatible with large-scale, non-cylindrical folding, the low levels of ductile deformation suggest that shape-change of the eastern SIC has been accomplished mainly by discontinuous deformation. This deformation mechanism may have accomplished bulk NW-SE shortening that was accommodated by reverse shearing within the SRSZ, resulting in large strike separations of SIC contacts observed in the western part of the impact structure. By contrast, the eastern SIC may have accomplished such shortening by brittleductile, non-cylindrical folding at the eastern terminus of the SRSZ. The complex post-impact deformation pattern of the central Sudbury Structure results from impact into an active orogen.
    Description: conference
    Keywords: 551 ; VEV 127 ; VAE 150 ; VKB 280 ; VAE 400 ; Ontario {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Impaktgesteine {Petrologie} ; Tektogenese {Geologie} ; Sudbury 〈Ontario, Region〉 ; Mehrfachringbassin ; Tiefengestein ; Impaktmetamorphes Gestein ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 73
    Publication Date: 2021-03-29
    Description: The anisotropy of magnetic susceptibility (AMS) can serve as a good indicator of strain in deformed carbonate rocks with diamagnetic susceptibility (Owens and Rutter 1978; de Wall 2000). However, the magnetic fabric due to the diamagnetic carbonate minerals is usually very weak and interpretation of the AMS in these rocks is often complicated by the presence of paramagnetic and ferromagnetic phases which overprint the diamagnetic subfabric. For this reason contributions from ferromagnetic and paramagnetic minerals to the AMS should be separated for a reliable interpretation of the AMS. Ferromagnetic contributions to the AMS can be separated by high-field measurements, using a torque magnetometer (Martin- Hernandez and Hirt 2001). The remaining paramagnetic and diamagnetic contributions can be discriminated by their different temperature dependencies. The paramagnetic susceptibility increases as an inverse function of temperature, whereas the diamagnetic part remains constant. Altogether, AMS measurements at high fields and low temperatures allow for the discrimination of all three subfabrics. Test measurements with the high-field torque magnetometer at liquid nitrogen temperature were performed. It is possible to keep the specimens at low temperature over the measurement period using a cryostat. The main problem is the suppression of mechanical disturbances during the measurement so that the sensitivity of the instrument is retained. The torque of paramagnetic minerals increases strongly at low temperature which results in an amplification of the paramagnetic subfabric. The quantitative separation of diamagnetic and paramagnetic subfabric is under investigation. The result is promising when there is a significant diamagnetic signal.
    Description: conference
    Keywords: 551 ; TQB 000 ; TOT 310 ; VAE 120 ; Erdmagnetische Verfahren {Geophysik} ; Gesteinsmagnetismus {Geophysik} ; Methodik {Strukturgeologie} ; Magnetische Suszeptibilität ; Drehmagnetometer
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 74
    Publication Date: 2021-03-29
    Description: Gravitative Massenverlagerungen entlang der Muschelkalkschichtstufe gehören zur natürlichen Morphodynamik. Durch die unterschiedliche Erosionsresistenz der relativ inkompetenten Ton- und Mergelsteine des Röt und der direkt darüber anstehenden widerstandsfähigeren Kalkgesteinen des Unteren Muschelkalks hat sich ein Steilhang im Übergang dieser Einheiten ausgeprägt. Ein unruhiges Relief des Schichtstufenhangs zeugt an vielen Stellen von gravitativen Massenverlagerungen. Zur detaillierten Kartierung dieser gravitativen Massenverlagerungen am Hünstollen im Göttinger Wald (10km nordöstlich von Göttingen) wurden Zweifrequenz-GPS-Messungen durchgeführt. Mittels differentieller Korrektur der gesammelten GPS-Daten konnte eine horizontale Präzision der Positionsbestimmung von bis zu 10 cm auf freier Fläche und bis zu 40 cm im Wald erreicht werden. Zusammen mit Schichtflächenmessungen ermöglichen die gesammelten Daten eine hochauflösende Darstellung einzelner Strukturelemente, Rückschlüsse auf die stattgefundenen Bewegungsabläufe sowie eine relative zeitliche Zuordnung der einzelnen Rutschkörper...
    Description: conference
    Keywords: 551 ; VEB 126 ; VDH 110 ; VDH 120 ; VAJ 100 ; VBG 100 ; Niedersächsisches Bergland {Geologie} ; Untere Trias ; Mittlere Trias ; Massenbewegungen {Geologie} ; Geologisches Kartieren ; Göttinger Wald ; Röt-Muschelkalk-Grenze ; Massentransport 〈Geowissenschaften〉 ; Kartierung
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 75
    Publication Date: 2021-03-29
    Description: Im nördlichen Teil des Appenin in Italien ist der metamorphe Komplex der Alpi Apuane in Form eines tektonischen Fensters sehr gut aufgeschlosssen. Die metamorphen Gesteine der Alpi Apuane — Metakarbonate, Kiesel- und Karbonatschiefer sowie Phyllite — sind aufgrund der Kollision der korsischsardischen Mikroplatte mit der italienischen Halbinsel im mm bis km- Maßstab verfaltet worden. Im zentralen Teil der Alpi Apuane biegt das generelle N–S Streichen der Faltenstrukturen in eine E–W Richtung um. Faltenstrukturen mit senkrecht zueinander stehenden Faltenachsen sind charakteristisches Strukturmerkmal u.a. ‘Metamorpher Kernkomplexe’ und Schlüssel zum Verständnis von Deformationsgeschichte und mechanismen. Die Entwicklung dieser Strukturen wird kontrovers diskutiert...
    Description: conference
    Keywords: 551 ; VEF 200 ; VKB 292 ; VKB 270 ; VKA 200 ; VAE 140 ; VAE 120 ; Italien {Geologie} ; Metamorphe Komplexe, übriges Europa {Petrologie} ; Produkte mechanischer Deformation {Petrologie} ; Gefügekunde der Gesteine ; Gesteinsdeformation {Strukturgeologie} ; Methodik {Strukturgeologie} ; Apuaner Alpen ; Karbonatgestein ; Marmor ; Deformation 〈Geologie〉 ; Faltentektonik ; Gefüge 〈Gesteinskunde〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 76
    Publication Date: 2021-03-29
    Description: Fission-track (FT) data always depend on the thermal history of a 3-D geological complex. Therefore it is expedient to display FT data sets in 3-D models. Such a model in which tectonic, sedimentological and hydrological features are combined can greatly improve the interpretation of the palaeo-thermal pattern derived from FT analyses. Since 1988 several FT studies have been conducted in the Black Forest (BF) (Michalski 1988, Wyss 2000, Timar- Geng et al. 2004, 2005). Timar-Geng et al. (2006) analyse the crystalline basement and the Permian Rotliegend beneath the Mesozoic units in the Tabular Jura (TJ) east of Basel, Switzerland, using samples taken from the three Nagra boreholes at Kaisten, Riniken and Leuggern. In particular Timar-Geng et al. (2005, 2006) characterise the thermal history of this pre-Mesozoic basement. For the BF they estimate at least one heating phase during the lower and middle Mesozoic while similar heating could not be observed in northern Switzerland. However, the FT-data in both regions show moderate to rapid cooling during the Cretaceous and Lower Eocene, which was followed by an Upper Eocene heating event. The software package GOCAD (Geological Objects Computer-Aided Design) was used to build a digital elevation model (DEM), which provide a new detailed view of these FT data sets. The model is located about 20 km east of Basel, Switzerland, and extends over an area of about 21km by 24 km and spans a vertical height difference of about 2 km. The data sets described above along with two additional FT analyses from the Buntsandstein which lies directly on the BF crystalline, were compiled and plotted at their topographic heights in the DEM. The FT central-ages (Galbraith & Laslett 1993) of this region range between 25 ± 2Ma and 98 ± 6.5 Ma. The topographic positions extend between −1412m at the Borehole Riniken and 960m in the BF with mean sea level as a reference. FT central-age isochron surfaces were drawn in order to visualize the thermal evolution within the model range. Because the FT central-ages also correspond to a closure temperature, these surfaces can also be considered an isotherm. The FT closure temperature of apatite is about 90±30°C (Laslett et al. 1987). Therefore each surface shows the position and shape of the ca. 90°C isotherm of a specific age. This 3-D model points out an important difference in the thermal evolution of the BF und the TJ. The vertical distance between the isothermal surfaces increases from north to south. Between 90Ma and 60Ma the ca. 90°C isotherm drops at the Kaisten borehole by 1000m while in the same time span in the BF a lowering of the same isotherm by 300m can be observed. In the eastern part of the model this feature is not as marked as in the west but nevertheless it is observable. To explain this entirely different thermal evolution it is necessary to turn to the tectonic and other geological features of the region. South of the exposed BF crystalline and beneath the TJ there lies an old Variscan structure: the Permo-Carboniferous trough (PCT). This trough strikes in WSWENE direction and extends from Lake Constance to the Bresse Graben and contains up to 6000m of Palaeozoic sediments. Additionally, some Variscan fault structures strike in WNW–ESE direction and cut both the BF an the PCT, for example the Eggberg Fault and the Vorwald Fault. Beside the tectonic structures the hydrological characteristics played an important role during the palaeo-thermal evolution. Circulating hot fluids controlled the thermal pattern. Variscan faults were often reactivated during the Mesozoic (e.g. Wetzel et al. 2003) and also during the formation of the Upper Rhine Graben. (e.g. Illies 1967) These faults are the major water-conducting features in the crystalline basement of the BF, joints and fracture networks are tributaries. Below the aquifers within the Mesozoic of the TJ, the PCT trough sediments predominantly act as an aquitard. Only the border faults of the trough were important pathways for fluids (Thury 1994). Considering the Mesozoic sedimentological history of the region it is unlikely that fault movements are responsible for the different palaeo-thermal pattern of the BF and the TJ. Only different magnitudes of heat flow caused by hydrothermal circulating fluids can explain the ‘warm’ BF crystalline in comparison to the ‘cold’ basement of the TJ at the transition between the Mesozoic and Tertiary.
    Description: conference
    Keywords: 551 ; VBN 500 ; VBN 200 ; VEB 143 ; Geochronologie einzelner Regionen im allgemeinen ; Radiometrische Altersbestimmung ; Oberrheinische Massen {Geologie} ; Schwarzwald 〈Südost〉 ; Kernspaltspurenmethode
    Language: German
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  • 77
    facet.materialart.
    Unknown
    Universitätsverlag Göttingen
    Publication Date: 2021-03-29
    Description: Regional strains in tectonically active volcanic provinces may have a profound influence on the mode of collapse caldera formation. Conversely, the deformation pattern, more specifically, the symmetry of plan-view strain fields imparted to caldera floors may assist in elucidating the regional deformation active during caldera formation. The symmetry of plan-view strain fields is chiefly controlled by the mode of floor subsidence, particularly whether subsidence is uniform, symmetric or asymmetric, portraying collapse mechanisms known respectively as plate, downsag and trapdoor. Plate and downsag subsidence generates centro-symmetric strain fields characterized by radial and concentric discontinuities and subvolcanic dikes. Such strain fields appear to develop preferably where magma pressure controls collapse. By contrast, rectilinear horizontal strain fields form under unidirectional stretching and generate normal faults and subvolcanic dikes transverse to the stretching direction. Rectilinear strain fields are typical for trapdoor subsidence but also for straight orogenic belts and suggests that the formation of both may be related. This was tested for six central Andean collapse calderas that formed between 10.5 and 2Ma and are located on prominent NW–SE striking fault zones. A combined geochronological and structural analysis of the Miocene Negra Muerta Caldera in particular was designed to better understand caldera formation associated with the prominent Olacapato – El Toro Fault Zone...
    Description: conference
    Keywords: 551 ; VAE 150 ; VEX 100 ; VAD 300 ; VAE 400 ; VAE 200 ; Strukturelle Erscheinungen {Strukturgeologie} ; Anden {Geologie} ; Vulkanformen und Vulkantypen {Geologie} ; Tektogenese {Geologie} ; Geodynamik der Lithosphäre {Geologie} ; Zentralanden ; Caldera ; Einsturzstruktur ; Deformation 〈Geologie〉 ; Geodynamik
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 78
    Publication Date: 2021-03-29
    Description: The Upper Rhine Graben forms the major segment of the Cenozoic Rift system of Western Europe. Although the rift was the target of many seismic and geological investigations, the style of lithospheric extension below the inferred faults, the depth to detachment, and the amounts of horizontal extension and lateral translation are still being debated. In this study, the date base to the Upper Rhine Graben was subjected to a finite element approach in order to include thermomechanical processes of the lithosphere as well as erosion and sedimentation. The study concentrated on the consequences of extension and lateral translational events on the structure and evolution in terms of basin geometry, sediment layer thicknesses, Moho elevation, and shoulder uplift on a lithospheric scale. The numerical approach was three dimensional in order to incorporate the lateral crustal heterogenities in the Upper Rhine area and the varying ambient stress field...
    Description: conference
    Keywords: 551 ; VEB 145 ; VAE 840 ; VAE 400 ; VAE 120 ; VBE 000 ; Rhein-Main-Tiefland {Geologie} ; Rifts {Geologie} ; Tektogenese {Geologie} ; Methodik {Strukturgeologie} ; Modellierung von Prozessen in der Geosphäre ; Oberrheingraben ; Tektonik ; Rifting ; Numerisches Modell
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 79
    Publication Date: 2021-03-29
    Description: Der Ság-hegy Vulkan Komplex befindet sich in dem Vulkanfeld der Kleinen Ungarischen Tiefebene. Eine 39Ar/40Ar Datierung ergab ein Alter von 5, 42 ± 0, 06Ma für den Ság-hegy (Wijbrans et al. 2004). Die Entwicklung des Vulkans weist zwei verschiedene Ereignisse auf. Als erstes trifft aufsteigendes Magma auf meteorisches Wasser in einer fluviolakustinen Umgebung (fuel-coolant interaction FCI). Die FCI von Wasser bzw. wassergesättigtem Sediment und Magma führte zur Bildung eines phreatomagmatischen Tuffrings. Nachdem das Wasserangebot aufgebraucht war, füllte sich das Innere des Tephrarings mit einem Lavasee. Lokal kollabierte der Tuffring, so dass Lava aus dem See herausfließen konnte. Durch die Anlage eines Steinbruches im zentralen Bereich des Vulkankomplexes ergibt sich ein 3-D Aufschluss mit hervorragenden Einblick auf die Intrusionsbeziehungen von Förderdykes, Sills und Überresten des Lavasees (Martin & Németh, 2004). In dieser Studie sollen die magnetischen Charakteristika einer Sektion von pyroklastischen Gesteinen, die von Dykes und Sills abgeschnitten wird, untersucht werden. Vorläufige Ergebnisse zeigen, dass die magnetische Suszeptibilität aller pyroklastischen Einheiten im Bereich der ferrimagnetischen Suszeptibilität liegt und von (2 − 20 × 10−3 SI variiert...
    Description: conference
    Keywords: 551 ; VAD 500 ; VAD 700 ; VKB 128 ; TOT 320 ; TQB 000 ; TSE 000 ; VEE 200 ; Exhalationen und postvulkanische Erscheinungen {Geologie} ; Regionaler Vulkanismus {Geologie} ; Pyroklastika {Petrologie} ; Paläomagnetismus {Geophysik} ; Erdmagnetische Verfahren {Geophysik} ; Südosteuropa {Geophysik} ; Pannonisches Becken {Geologie} ; Ungarische Tiefebene ; Pyroklastit ; Magnetische Suszeptibilität
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 80
    Publication Date: 2021-03-29
    Description: Geology as a science has an important visual component and the knowledge of any geologist is deeply linked to visual experience of rock outcrops, thin sections and analytical images. One of the shortcomings of most geological images such as maps, cross sections and outcrop photographs is that they are 2D, while processes geologists are interested in are typically occurring in 3D space. The 3D geometry of faults, fractures and joints is crucial to quantify geological processes related to fracture mechanics, such as hydrothermal mineralization and ground water flow, but also geotechnical problems such as rock mass stability. A number of studies have shown that some geological structures can be described with a scale invariant, fractal distribution. So far these observations on which these findings are based were restricted to one and two dimensions and has been difficult to obtain a full spatial geometric picture of fracture sets from rock outcrops, because much of the rock is not directly accessible. However, without taking into account the spatial distribution of geological structures the true geometry of joint patterns cannot be fully described and scaling laws, fractal or not, cannot be derived. We present images of joint patterns based on datasets acquired by digital photographs which are processed to three dimensional images using the photogrammetry software Siro3D. This technique allows to obtain a highly accurate 3D picture of the visible outcrop. The spatial pattern of joints in nature is investigated using the software SiroJoint. For the analysis of joint systems a large data set was collected from the Heavitree Quarzite at Ormiston Gorge, near Alice Springs. The Heavitree Quartzite is fragmented by a spectacularly regular three-dimensional joint pattern, which is repeated at different scales and therefore represents a perfect laboratory for our investigations (Hobbs 1993). Siro3D generates a spatially fully referenced 3D image from overlapping digital images, such that each pixel of the image is assigned spatial coordinates. The software SiroJoint routinely constructs planes from the intersection of the rock-face with the linear trace of planar features (Poropat 2001). It provides stereographic plots of structural elements and additionally measures joint persistence, area, and joint spacing. Our measurements allow to analyse geometrical scaling relationships of joint sets with high accuracy and will help explore the character of their 3D complexity. Several hundred joint planes were defined with SiroJoint in an Ormiston Gorge outcrop. Three different joint sets can be distinguished. Joint set one and two are characterized by steeply inclined planes with joint spacings ranging between 2 cm to 40 cm and 2 cm to 10m respectively. Both joints sets depict a power law distribution in joint spacing/frequency plots. The third set is defined by a subhorizontal orientation. It shows a very regular spacing in the meter scale and lacks an exponential distribution. We intend to use the results as a basis to compare observed fracture pattern with those generated by computational methods like Iterated Function Systems. This might help to understand how physical rock properties influence the spatial complexity of fracture systems and develop constitutive scaling relationships for certain rock types.
    Description: conference
    Keywords: 551 ; VAE 120 ; VBH 000 ; VAE 150 ; Methodik {Strukturgeologie} ; Fernerkundung ; Strukturelle Erscheinungen {Strukturgeologie} ; Klüftung ; Bruch 〈Geologie〉 ; Photogrammetrie ; Dreidimensionale Rekonstruktion
    Language: German
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  • 81
    Publication Date: 2021-03-29
    Description: Die Region - mit den markanten Erhebungen des Hohen Meißners und des Thüringer Waldes - stellt geologisch und bergbaugeschichtlich einen Teil der deutschen Mittelgebirge dar, der Fachleute sowie Amateure und Naturfreunde gleichermaßen fasziniert. Die vorliegende Bibliographie versucht erstmals länderübergreifend die umfangreiche Fachliteratur der Dreiländer-Region zu erschließen. Dabei wurden sowohl fachwissenschaftliche als auch heimatkundliche Publikationen und unveröffentlichtes Material berücksichtigt.
    Description: bibliography
    Keywords: 551 ; VEB 125 ; VEB 126 ; Hessisch-thüringisches Bergland {Geologie} ; Niedersächsisches Bergland {Geologie} ; Nordhessen ; Thüringen 〈West〉 ; Niedersachsen 〈Süd〉 ; Werra-Meißner-Kreis ; Geowissenschaften ; Bergbau ; Bibliographie ; 38.55 ; 57.01
    Language: German
    Type: monograph , publishedVersion , monograph
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  • 82
    Publication Date: 2021-03-29
    Description: Grain boundary migration during dynamic recrystallization of quartz results in grain boundary suturing of various extent. The geometry of the sutured boundaries is affected not only by temperature, strain rate, finite strain and differential stress, but also by internal properties such as the defect distribution and crystallographic orientations. Consequently, the grain boundary geometry may provide information about these conditions and properties. In continuation of a previous study (Kuntcheva et al.) the complete crystallographic orientation of quartz grain boundaries was measured, based on a combination of electron backscatter diffraction (EBSD) and universal-stage (U-stage) measurements. For this purpose a sample of granite from the northern Aar Massif (Central Alps, Switzerland) was taken, deformed at temperatures up to 300–350°C at the end of the Lepontine event of the Alpine Orogenesis...
    Description: conference
    Keywords: 551 ; VKA 200 ; VAE 120 ; VAE 130 ; Gefügekunde der Gesteine ; Methodik {Strukturgeologie} ; Geomechanik ; Aare-Massiv ; Granitgneis ; Quarz ; Rekristallisationstextur
    Language: German
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  • 83
    Publication Date: 2021-03-29
    Description: Am Ostrand des Hauzenberger Plutons im südlichen Bayerischen Wald treten Ganggesteine auf, die spät- bis postvariskische Granitoide und ihre Rahmengesteine (anatektische und diatektische Gneise) durchschlagen. Die Intrusion der Gänge wurde auf 307Ma datiert (Siebel, pers. comm.). Sie stellen somit das jüngste magmatische Ereignis mit deutlichem zeitlichen Hiatus zur Platznahme der Granitplutone des Bayerischen Waldes zwischen 316 und 324Ma (Propach 2000) dar. Die Hauptverbreitung dieser Ganggesteine liegt in einem herzynisch verlaufenden Zug von Oberndorf im Nordwesten über Waldkirchen zum Oberfrauenwald und weiter nachWegscheid im Südosten. Die Gänge streichen in den zwei Hauptrichtungen WNW–ESE (etwa 140°), also in etwa parallel zum Bayerischen Pfahl, sowie annähernd N–S (etwa 170°). Die Gänge stehen generell saiger und haben Mächtigkeiten von wenigen dm bis zu 15 m. An 14 Gängen wurde im Gelände und Labor die magnetische Suszeptibilität gemessen.
    Description: conference
    Keywords: 551 ; VEB 211 ; VKB 130 ; TSB 000 ; TOT 310 ; TQB 000 ; VKA 200 ; Baden Württemberg {Geologie} ; Petrologie der Ganggesteine ; Mitteleuropa {Geophysik} ; Gesteinsmagnetismus {Geophysik} ; Erdmagnetische Verfahren {Geophysik} ; Gefügekunde der Gesteine ; Bayerischer Wald ; Gang 〈Geologie〉 ; Magnetische Suszeptibilität ; Gefüge 〈Gesteinskunde〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 84
    Publication Date: 2021-03-29
    Description: The Austroalpine microplate traces the Alpine collision event between the Africa-related southern Alpine realm and the European continent. The southern margin of this microplate, the basement to the north of Meran (including Texel unit and Schneeberg Zug) is characterized by regional eo-Alpine high-pressure metamorphism (Hoinkes & Thöni, 1987). PT conditions decrease from SE (Texel unit) to the pre-alpine basement in the NW. The HP Rocks were exhumed within a ca. 15km broad SW-NE-striking, NWdipping high strain zone (Sölva et al. 2001). The high-pressure Texel crystalline is tectonically underlain by the Campo unit in the south and overlain by the Ötztal-Stubai Basement in the north(west). The Schneeberg Zug forms an up to 5km thick shear zone at its base, representing the study area. It shows normal-sense kinematics and separates pre-Alpine basement rocks in the hanging wall from high-pressure rocks in the footwall, the Texel unit. These were emplaced on top of pre-Alpine basement rocks (Campo unit) by an eo-Alpine ductile thrust. Lithologically the western termination of the Schneeberg Zug comprises characteristic garnet micaschists, marble layers, amphibolites, quartzites, hornblende-garben-schists and calcschists. These lithologies are called Bunte Serie (Mauracher, 1981) and differ from the polyphase adjacent Texel unit and the polymetamorphic basement rocks in the hanging wall due to their lithological content and their monometamorphic evolution. Petrological and geochronological investigations on the eastern continuation of these characteristic metapelitic rocks evidence the time of garnet growth during D1 close to the Cretaceous pressure peak. Sm-Nd isochron data of these continuously zoned garnets yielded crystallization ages between 90 and 95 Ma. Preliminary structural investigations yielded four major deformation events: D1 produced a compositional layering and a mylonitic foliation; generally this ductile deformation in the northwestern portion of the Schneeberg Zug is characterized by contemporaneous shearing and folding forming isoclinal folds with axes oriented parallel to the NW–SE plunging stretching lineation. Deformation stage D2 formed tight folds with steep NW to WSW plunging axes and NW to W dipping axial planes, which refold the D1 related structures. Deformation stage D3 is characterized by a crenulation with NW-plunging axes and NW-dipping axial planes. Lower greenschist-facies shear-zones dipping to the W and with shear sense top to W– WNW represent the last ductile event. They crosscut the older structural inventory. Brittle deformation evidences normal faulting reactivating the NW dipping main foliation as well as related dextral strike slip movement. Geochronological data and structural investigations indicate a continuous eo- Alpine tectono-metamorphic evolution, which started at high grade conditions homogenously distributed over the whole shear zone. With decreasing temperature conditions the deformation progressively partitioned into distinct shear zones.
    Description: conference
    Keywords: 551 ; VEB 163 ; VAE 150 ; VAE 850 ; VKB 291 ; Zentrale Ostalpen {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Festländische Lineamente {Geologie} ; Metamorphe Komplexe, Alpen {Petrologie} ; Südtirol ; Campo-Kristallin ; Scherzone
    Language: German
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  • 85
    Publication Date: 2021-03-29
    Description: Die Exkursion stellt repräsentative Aufschlüsse triassischer und jurassischer Sedimente aus der direkten Umgebung von Göttingen vor. Dabei werden deren stratigraphische Stellung, Ablagerungsmilieus und Fossilgemeinschaften diskutiert. Zunächst werden Aufschlüsse auf der östlichen Schulter des Leinetalgrabens (Muschelkalk- Plateau des Göttinger Waldes), danach auch im Leinetalgraben selbst (Keuper, Schwarzjura) besucht. Hinreichend gute Aufschlußbedingungen sind vor allem in Tongruben (Röt, Mittlerer Keuper, Schwarzjura) und Steinbrüchen (Unterer Muschelkalk) gegeben.
    Description: excursionguide
    Keywords: 551 ; VEB 126 ; VDH 100 ; VDH 200 ; Niedersächsisches Bergland {Geologie} ; Trias ; Jura ; Göttingen ; Geologie ; Trias ; Jura 〈Geologie〉 ; 38.10
    Language: German
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  • 86
    Publication Date: 2021-03-29
    Description: Basement-cover-interfaces are important crustal boundaries. In many cases they act as detachment horizons. Criteria like pre-erosional basement characteristics, intensity of palaeoweathering and post-erosional processes during burial stage lead to a huge variety of observable alteration and fabric features of basement-cover-interfaces, which may influence the shear-strength. Unconformity-parallel planar fabrics in the weathering profile were facilitated by palaeo-alteration and later processes (Angerer 2005 unpubl. data). Such fabrics may be a factor for lowering the shear-strength (e.g. Wintsch et al. 1995). The probably ubiquitous existence of those fabrics at basement-coverinterfaces is investigated in case studies by means of AMS-fabric analysis, which is a sensitive indicator of rock fabric changes. The present case study is based on sections from two drill cores across the erosional unconformity between Fennoscandian Granite (Revsund) and Cambrian Gärdsjön Fm. (Långviken SGU 73007 and Hara 79002) (petrographic descriptions in Gee, 1978 and Gee et al. 1982).
    Description: conference
    Keywords: 551 ; VAH 000 ; VAE 813 ; TOT 310 ; VED 200 ; Verwitterung {Geologie} ; Kaledonische Orogene {Geologie} ; Gesteinsmagnetismus {Geophysik} ; Schweden {Geologie} ; Mittelschweden ; Kaledoniden ; Verwitterungshorizont ; Magnetische Anisotropie ; Gesteinsgefüge ; Magnetische Suszeptibiblität
    Language: German
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  • 87
    Publication Date: 2021-03-29
    Description: The suevitic Onaping Formation overlies the layered Main Mass of the 1.85Ga Sudbury Igneous Complex (SIC) of the Sudbury Impact Structure, Ontario. The Formation consists of four Members, namely from top to bottom, the Black, the Green, the Gray and the Basal. Post-impact NWSE shortening during the Penokean Orogeny (ca. 1.9–1.75 Ga) affected the Onaping Formation and led to the lobate shape of the SIC in plan view. In order to investigate the possible fold origin of the NE-lobe of the SIC, a field-based structural analysis of the Onaping Formation was conducted in the Frenchman Lake area. The analysis is based on structural measurements at 580 stations and encompasses the orientation of mineral shape fabrics as well as their intensity. In addition to these quantities, lithological variation and metamorphic overprint of the Onaping Formation was examined. Special attention was paid thereby to the Green Member since previous workers stated that it forms a continuous unit at the base of the Black Member...
    Description: conference
    Keywords: 551 ; VKB 280 ; VKB 295 ; VAE 140 ; VEV 127 ; VKA 200 ; Impaktgesteine {Petrologie} ; Metamorphe Komplexe, Nordamerika {Petrologie} ; Gesteinsdeformation {Strukturgeologie} ; Ontario {Geologie} ; Gefügekunde der Gesteine ; Sudbury 〈Ontario. Region〉 ; Mehrfachringbassin ; Proterozoikum ; Impaktmetamorphes Gestein ; Suevit ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 88
    Publication Date: 2021-03-29
    Description: Lokalisierung unter retrograden Deformationsbedingungen kann häufig in groß-maßstäblichen Scherzonen beobachtet werden. Dabei nimmt die Scherzonenbreite kontinuierlich ab. Gleichzeitig passt sich das Gefüge (Korngröße, Kornform, Kornorientierung, Zwillingsdichte, kristallographische Orientierung, usw.) den neuen Umgebungsbedingungen (Temperatur, Spannung und Verformungsrate) an. Die Glarner Hauptüberschiebung in den Ostschweizer Alpen ist ein gutes Beispiel, um das Ausmaß und die Entwicklung einer Verformungslokalisierung zu bestimmen. In der Vergangenheit wurde sie detailliert in Hinblick auf ihre Isotopenverteilung und daraus resultierenden Fluidbewegungen und Überprägungen untersucht. Dies erlaubt das Zusammenspiel der Lokalisierung und der Fluidüberprägung zur Zeit der Platznahme der Glarnerdecke zu bestimmen...
    Description: conference
    Keywords: 551 ; VAE 130 ; VAE 400 ; VAE 150 ; VJC 400 ; VEB 168 ; Geomechanik ; Tektogenese {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Fluid-Gestein-Wechselwirkungen {Geochemie} ; Schweizer Alpen {Geologie} ; Glarner Alpen ; Scherzone ; Deformation 〈Geologie〉 ; Fluid-Fels-System
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 89
    Publication Date: 2021-03-29
    Description: Als Teil des International Continental Drilling Projects (ICDP), wurde von März bis September 1999 im Rahmen des Hawai’i Scientific Drilling Projects (HSDP) die etwa 3109m tiefe HSDP-2 Bohrung in der Nähe von Hilo auf Big Island, Hawai’i niedergebracht. Die mit einem Durchmesser von 98mm (3.8500) durchgehend gekernte Bohrung, durchteuft sowohl die subaerischen Einheiten des Mauna Loa, als auch die darunter liegenden submarinen Laven des Mauna Kea. Ab etwa 1080m Teufe wurden die jüngsten, während der Entwicklung dieses Vulkans abgelagerten submarinen Laven erbohrt. Die Verteilung von Hyaloklastiten, Pillowlaven, massiver Intrusiva sowie sedimentärer Ablagerungen, wurde durch die lithologische Beschreibung des durchgehend geförderten Kernprofils von DePaolo et al. (1999) aufgenommen. Verschiedene Autoren, wie z.B. Bücker et al. (1999) oder Helm-Clark et al. (2004) haben bereits gezeigt, dass sich Messungen der natürlichen Gammastrahlung (GR), die üblicherweise sehr gut zur lithologischen Einteilung von Gesteinen herangezogen werden können, in vergleichbaren Bohrungen nur sehr bedingt zur primären Unterscheidung basaltischer Gesteinseinheiten eignen. Dies ist vor allem auf die sehr geringe Variation des K-, U- und Th-Gehalts der Basalte zurückzuführen. Daher wurden von der Operational Support Group (OSG) des GFZ-Potsdam im November 2002 bohrlochgeophysikalische Messungen in dem 98mm Bohrloch in einem Bereich von etwa 1830 bis 2615m durchgeführt. Diese wurden speziell zum Test einer Bohrlochsonde zur Messung der magnetischen Suszeptibilität (MS) im Rahmen des DFG-Projektes Wa 1015/4 angesetzt. Dazu wurde die MSdH-2 Sonde der OSG, hergestellt von der Fa. Antares GmbH (Stuhr, Germany) eingesetzt.
    Description: conference
    Keywords: 551 ; VAD 400 ; TOT 310 ; TQG 000 ; VEV 285 ; VBL 500 ; VKB 124 ; Vulkanische Förderprodukte {Geologie} ; Gesteinsmagnetismus {Geophysik} ; Geophysikalische Bohrlochmessungen ; Hawaii {Geologie} ; Geologische Bohrungen in einzelnen Regionen ; Basaltische Vulkanite {Petrologie} ; Mauna Kea ; Tiefbohrung ; Bohrlochgeophysik ; Magnetische Suszeptibilität ; Lava ; Basalt
    Language: German
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  • 90
    Publication Date: 2021-03-29
    Description: Dykes are magma-driven extension fractures and the main conduits for magma in volcanic eruptions. To understand the mechanics of dyke emplacement is thus essential to assess volcanic hazards. To improve the understanding of the processes of dyke initiation from shallow magma chambers and dyke propagation through a mechanicallylayered crust, field measurements and observations from Tenerife (Canary Islands) are used and compared with the results from numerical models. Careful studies of 550 dykes in three profiles in the Anaga massif (Tenerife) include measurements of dyke geometry and orientation. The results of these measurements show that dykes have been injected from a deep-seated reservoir during the shield-building phase. Furthermore, the dyke attitudes agree with the main axial trends of Tenerife that are preserved in the old massifs of Teno, Anaga, and Roque del Conde...
    Description: conference
    Keywords: 551 ; VAE 150 ; VEZ 130 ; Strukturelle Erscheinungen {Strukturgeologie} ; Inselgruppen {Atlantischer Ozean: Geologie} ; Teneriffa ; Gang 〈Geologie〉
    Language: German
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  • 91
    Publication Date: 2021-03-29
    Description: The North Equatorial Panafrican belt is constituted by orthogneissified metamorphic and magmatic sets linked to tectonometamorphic events of the neoproterozoic orogeny. This belt whose formations are situated in the North of the congo craton is divided into three distinct geodynamic domains: a southern domain, a northern domain and a central domain. The deformation and metamorphism relationships are a function of the different geodynamic domains of the belt. The central domains, to which belongs the Banefo region, is affected by large strike-slip faults among which is the central cameroonian shear zone. This domain is marked out by numerous syntectonic granitoids. At Banefo (NE Bafoussam, West Cameroon), those massifs are mainly constituted by mylotinised orthogneisses and granites of various degrees. The country rock is made up of gneiss and amphibolite. In the Banefo massifs, the orthogneiss is the least deformed petrographic unit. It shows a heterogranular granoblastic texture with a mineral assemblage formed by quartz, K-feldspars, biotite, etc., within the orthogneiss, remains of magmatic fluidality can still be observed marked by feldspar megacrystal. Field observations reveal a net progression of the intensity of deformation of orthogeisses to ultramylotinised granites having an identical chemical composition as the orthogneisses...
    Description: conference
    Keywords: 551 ; VKA 200 ; VAE 140 ; VAE 850 ; VKB 270 ; VEP 500 ; Gefügekunde der Gesteine ; Gesteinsdeformation {Strukturgeologie} ; Festländische Lineamente {Geologie} ; Produkte mechanischer Deformation {Petrologie} ; Kamerun {Geologie} ; Kamerun-Linie ; Granitgneis ; Mylonit ; Deformation 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 92
    Publication Date: 2021-03-29
    Description: The geothermal field at Reykjanes peninsula is located at the boundary where the submarine Reykjanes Ridge passes over into the rift zone of southwestern Iceland. The geothermal field coincides with a magnetic low in the aeromagnetic anomaly map and is situated within a dense NE–SW fissure and fault zone. Surface geology is characterized by different historic fissure eruptions (youngest from 1226AD), shield lava (12.5–14.5 ka) and intercalated pillow basalt–hyaloclastite ridges probably formed during the last glacial episode (14.5–20 ka). During a field magnetic study in the vicinity of the geothermal field in summer 2005 different volcanic rock units have been sampled to correlate rock magnetic and magneto-mineralogical properties with magnetic field intensity. Additionally, measurements on a dense dolerite intrusion, recovered from the RN–19 borehole (2245–2248m depth) in May 2005 within the frame of IDDP, should shed light on the influence of crustal rocks on the total magnetic field intensity. Generally, the natural remanent magnetization and magnetic susceptibility, measured on rock specimen, is high, ranging between 2.5 and 33.6Am−1 and 2–37 ×10−3 SI, respectively...
    Description: conference
    Keywords: 551 ; TOT 320 ; TSZ 100 ; TSD 000 ; TQB 000 ; VED 500 ; VEZ 110 ; VAE 890 ; VKA 150 ; VKB 326 ; Paläomagnetismus {Geophysik} ; Atlantischer Ozean {Geophysik} ; Nordeuropa {Geophysik} ; Erdmagnetische Verfahren {Geophysik} ; Island {Geologie} ; Teilgebiete {Geologie} ; Ozeanische Kruste {Tektonik} ; Physikalische Petrologie ; Magnetische Stratigraphie {Sedimentologie} ; Reykjanes ; Reykjanesrücken ; Ergussgestein ; Magnetische Suszeptibilität ; Magnetostratigraphie
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 93
    Publication Date: 2021-03-29
    Description: Der oberflächennahe geologische Untergrund Norddeutschlands wird durch das Auftreten zahlreicher Salzvorkommen geprägt. Während der Triaszeit und des unteren Juras herrschte ein EW gerichtetes, extensives tektonisches Regime vor. Durch zusätzliche Umlagerung klastischer Sedimente wurden darunter liegende Salzmassen permischen Alters (Zechstein) aus Tiefen von bis zu 5000Metern an die Erdoberfläche empor gepresst. Durch diesen Salzaufstieg wurden darüber liegende mesozoische Schichten durchschlagen, randlich der Salzdiapire deformiert und teilweise mitgeschleppt. Eine letzte Phase salztektonischer Aktivitäten während der oberen Kreide und des unteren Tertiärs zeichnet sich zum einen durch weiteren Salzaufstieg aus und zum anderen durch horizontale Einengung der Salzstöcke. Begleitgesteine der Salze, wie Gips, Anhydrit, und Karst, sowie Tertiäre und Quartäre Ablagerungen überlagern die Salzstöcke mit unterschiedlichen Mächtigkeiten. Das humide Klima Norddeutschlands begünstigt natürliche Auslaugungsprozesse (Subrosion) der Evaporite durch Grundwasser. Je nach Tiefenlage des Salzspiegels (Salzstock Lüneburg: −20 bis −40 m; Salzstock Othmarschen-Langenfelde (Hamburg): ca 0 bis −250 m) kann es zu intensiver Hohlraumbildung im tieferen Untergrund kommen. Die fortschreitende Vergrößerung einer solchen Höhle steht in Abhängigkeit zur Intensität der Lösungsprozesse, während die Stabilität des Hohlraumes zusätzlich von der Materialbeschaffenheit abhängt. So können feste Gesteine oder bindige Böden zwar ein stabiles Höhlendach bilden, jedoch ist bei andauernden Lösungsprozessen langfristig ein statisches Versagen des Höhlendaches unvermeidlich. Der damit verbundene Kollaps und die Verfüllung des Hohlraumes mit Sediment spiegelt sich häufig in Form von sub-zirkularen und konischen Einsturzröhren oder weitläufigen morphologischen Trichtern an der Erdoberfläche wieder. Die Terminologie der Erdfälle wird anhand der Subsidenzrate gewählt...
    Description: conference
    Keywords: 551 ; TQD 800 ; VAO 120 ; VEB 110 ; Georadar {Geophysik} ; Karsterscheinungen an der Erdoberfläche ; Norddeutsche Senke {Geologie} ; Hamburg 〈Region〉 ; Lüneburg 〈Region〉 ; Erdfall ; Elektromagnetische Reflexionsmethode ; Risikoanalyse ; Salztektonik
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 94
    Publication Date: 2021-03-29
    Description: Structural analysis of Paleozoic Middle and Upper Austroalpine (MAA, UAA) units of the Gurktal Nappe Complex (GNC) in combination with electron microprobe analyses of multiphase garnets reveal a complex Variscan and Alpidic tectonometamorphic evolution of the GNC. Our study is focussed on the UAA ‘Murau Nappe’ and its tectonic transition to the MAA respectively to the overlying UAA Stolzalpen Nappe. The ‘Murau Nappe’ may rather be interpreted as a major zone of imbricate thrust slices of the underlying and overlying units than a distinct nappe. The results of our study lead to a reinterpretation of the ‘Murau Nappe’ as a major shear zone generated during the Eo-Alpine thrusting of the Stolzalpen Nappe over the MAA. Concerning the central GNC we conclude, that the genetic term ‘Murau Nappe’ for the lower UAA unit between MAA and Stolzalpen Nappe is not valid. Instead, its reinterpretation as a major shear zone (‘Murau shear zone’), genetically belonging to the MAA, generated during Eo-Alpine overthrusting of the Stolzalpen Nappe, is favoured. The Mesozoic Stangalm unit is interpreted as a local sequence imbricated during the northward movement of the MAA units.
    Description: conference
    Keywords: 551 ; VEB 163 ; VAE 400 ; VKB 291 ; VAE 811 ; Zentrale Ostalpen {Geologie} ; Tektogenese {Geologie} ; Metamorphe Komplexe, Alpen {Petrologie} ; Alpidische Orogene {Geologie} ; Gurktaler Decke ; Alpidische Gebirgsbildung ; Tektogenese ; Metamorphose 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 95
    Publication Date: 2021-03-29
    Description: Structural analysts are often faced with the problem of identifying prominent structural discontinuities covered by post-tectonic sedimentary or volcanic rocks. Gravity fields are often used to delineate the trace of buried discontinuities but are frequently found to be too crude to localize discontinuities adequately. Here, we introduce the importance of dip curvature of the isostatic residual gravity for identifying upper-crustal discontinuities. The relationship between Bouguer gravity, isostatic residual gravity and its dip curvature, first-order structural elements and distribution of Neogene volcanic rocks was examined in the central Andean plateau, more specifically, the southern Altiplano and the Puna...
    Description: conference
    Keywords: 551 ; TSX 000 ; TQA 000 ; VAE 811 ; VEX 100 ; Südamerika {Geophysik} ; Gravimetrische Verfahren {Geophysik} ; Alpidische Orogene {Geologie} ; Anden {Geologie} ; Zentralanden ; Erdkruste ; Diskontinuität 〈Geologie〉 ; Gravimetrie
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 96
    Publication Date: 2021-03-29
    Description: Der Holozäne Thingvellir Spaltenschwarm ist Teil des 60 km langen Hengill Vulkansystems, das sich in der Westvulkanischen Zone in Island befindet und ein etwa 9000 Jahre altes basaltisches Lavafeld nördlich des Sees Thingvallavatn durchquert. Dieser Spaltenschwarm enthält einige der größten postglazialen Verwerfungen und Brüche, die in der Riftzone Islands anzutreffen sind. Das Zentrum des Hengill Vulkansystems bildet der 0.8 Ma alte gleichnamige Vulkan. Der Gipfel des Vulkans ist durchzogen von NE-SW streichenden Abschiebungen, von denen einige bis zum See Thingvallavatn verfolgt werden können. Der Thingvellir Spaltenschwarm wird von nahezu vertikalen Zugbrüchen und geöffneten Abschiebungen dominiert...
    Description: conference
    Keywords: 551 ; VAE 830 ; VAE 150 ; VED 500 ; Bruchschollenstrukturen {Geologie} ; Strukturelle Erscheinungen {Strukturgeologie} ; Island {Geologie} ; Island ; Thingvellir ; Abschiebung 〉Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 97
    Publication Date: 2021-03-29
    Description: Die Insel Kreta bildet den südlichen Rand der externen Helleniden, welche üblicherweise in zwei Deckenstapel untergliedert werden: Die unteren Decken (Plattenkalk und Phyllit-Quarzit- Einheit) sind durch eine alpidische HP-Metamorphose (Oligozän/Miozän) gekennzeichnet (Seidel et al. 1982, Jolivet et al. 1996), welche im Hangenden bislang nicht nachgewiesen wurde. Die Oberen Decken (i.w. Tripolitza- und Pindos-Einheit) bestehen aus karbonatischen Gesteinen und sind für eine petrologische PT-Abschätzung ungeeignet. Aufgrund des Gesteinshabitus wurden sie als unmetamorph eingestuft. Schlußfolgernd wird der Kontakt der beiden Stapel seit etwa zwanzig Jahren als krustales Megadetachment (‚Kreta- Detachment‘) aufgefaßt (Jolivet et al. 1996, Fassoulas et al. 1994, Kilias et al. 1994), wobei Versatzbeträge von über 100km angenommen werden (Ring et al. 2001, 2001). Ziel dieser Arbeit ist es Gemeinsamkeiten und Unterschiede der unmittelbar an das Detachment angrenzenden Einheiten herauszuarbeiten, um Rückschlüsse auf die tatsächliche Signifikanz der Störungszone zu ziehen.
    Description: conference
    Keywords: 551 ; VEF 000 ; VAE 140 ; VAE 400 ; VKA 200 ; VKB 292 ; VKB 250 ; Südeuropa und Mittelmeergebiet {Geologie} ; Gesteinsdeformation {Strukturgeologie} ; Tektogenese {Geologie} ; Gefügekunde der Gesteine ; Metamorphe Komplexe, übriges Europa {Petrologie} ; Metasedimente {Petrologie} ; Kreta ; Abscherung ; Deformation 〈Geologie〉 ; Alpidische Gebirgsbildung ; Metamorphose 〈Geologie〉
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 98
    Publication Date: 2021-03-29
    Description: The EZ is an approximately 20km long and 2–3km wide coherent unit of the Tauern Window in the Eastern Alps. It is sandwiched between the Venedigerand the Glockner Nappe. While rocks in the EZ experienced HP metamorphic conditions (24 kbar/650°C), rocks from the underlying Venediger Nappe and the overlying Glockner Nappe only record lower alpine metamorphic conditions with peak pressures not exceeding 10 and 8 kbar, respectively. While metamorphism in the EZ is well dated with an average age of 31.5±0.7Ma (Glodny et al. 2005) the final emplacement of these different nappes is still under debate. Our Rb-Sr-data indicate that top-N thrusting at the base and large-scale folding of the EZ was coeval with sinistral strike-slip faulting at its upper boundary and eclogite-facies metamorphism in the EZ. The data also indicate that today’s nappe architecture must have been established in less than 2Ma after the eclogite facies metamorphism in the EZ. Very fast exhumation of the EZ was accomplished in a transpressional setting, which might explain why the exposed EZ is such a small unit.
    Description: conference
    Keywords: 551 ; VEB 163 ; VKB 291 ; VAE 400 ; VBN 500 ; VAE 811 ; Zentrale Ostalpen {Geologie} ; Metamorphe Komplexe, Alpen {Petrologie} ; Tektogenese {Geologie} ; Geochronologie einzelner Regionen im allgemeinen ; Alpidische Orogene {Geologie} ; Tauernfenster ; Decke 〈Geologie〉 ; Eklogit ; Rubidium-Strontium-Methode ; Überschiebung ; Oligozän
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 99
    Publication Date: 2021-03-29
    Description: During impact, rocks at the surface and accessible depths encounter extreme conditions. The hydrostatic component of the shock wave-associatedstress, the so-called shock pressure, canreach several tens of GPa in the central part of the structure. The shock crust and its comprehensive experimental calibration. Two distinct types of quartz microstructure in charnockitic target rocks and quartz veins of the Charlevoix impact structure are compared and contrasted in order to distinguish shock-induced microstructures that indicate a high hydrostatic stress component of the shock wave-associated stress from those that indicate a high deviatoric component, as well as associated microstructures that were generated during post-shock relaxation...
    Description: conference
    Keywords: 551 ; VKA 200 ; VAE 140 ; VHB 400 ; VKB 280 ; VEB 128 ; Gefügekunde der Gesteine ; Gesteinsdeformation {Strukturgeologie} ; Oxide und Hydroxide {Mineralogie} ; Impaktgesteine {Petrologie} ; Saxothuringikum {Geologie} ; Charlevoix 〈Quebec〉 ; Impaktstruktur ; Impaltmetamorphes Gestein ; Deformation 〈Geologie〉 ; Quarz ; Mikrostruktur
    Language: German
    Type: anthologyArticle , publishedVersion
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  • 100
    Publication Date: 2021-03-29
    Description: The tectonic history of the Kamchatka Peninsula is dominated by continuous accumulation and amalgamation of terranes with different origins, which were delivered by convergence between the Pacific plate and in former times, the Kula plate against Eurasia (Freitag, 2002). The Kronotsky and Cape Kamchatka Peninsulas show that the collision of terranes and the resulting tectonics are still important for major parts of East-Kamchatka. While the collision of the Kronotsky Peninsula is sorely influenced by the convergence of the Pacific plate, the Cape Kamchatka Peninsula is affected by the collision of the Aleutian Arc with Kamchatka, what gives the opportunity to compare two different processes that resulted in the amalgamation of terranes to Kamchatka.
    Description: conference
    Keywords: 551 ; VEG 190 ; VAE 400 ; VAE 300 ; VAE 120 ; VBJ 000 ; Koriakia-Kamtchatkasystem {Geologie} ; Tektogenese {Geologie} ; Epirogenese {{Geologie}} ; Methodik {Strukturgeologie} ; Satellitenbildgeologie ; Kamtschatka 〈Oblast〉 ; Neotektonik ; Fernerkundung
    Language: German
    Type: anthologyArticle , publishedVersion
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