ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Springer Nature  (269,852)
  • AGU
  • AGU (American Geological Union)
  • American Meteorological Society
  • 2020-2023  (169)
  • 2015-2019  (259,934)
  • 1980-1984  (25,767)
Collection
Keywords
Publisher
Years
Year
  • 1
    facet.materialart.
    Unknown
    Cluster analysis of downscaled and explicitly simulated North Atlantic tropical cyclone tracks (2015)
    American Meteorological Society
    Details
    Publication Date: 2020-11-18
    Description: A realistic representation of the North Atlantic tropical cyclone tracks is crucial as it allows, for example, explaining potential changes in U.S. landfalling systems. Here, the authors present a tentative study that examines the ability of recent climate models to represent North Atlantic tropical cyclone tracks. Tracks from two types of climate models are evaluated: explicit tracks are obtained from tropical cyclones simulated in regional or global climate models with moderate to high horizontal resolution (1°–0.25°), and downscaled tracks are obtained using a downscaling technique with large-scale environmental fields from a subset of these models. For both configurations, tracks are objectively separated into four groups using a cluster technique, leading to a zonal and a meridional separation of the tracks. The meridional separation largely captures the separation between deep tropical and subtropical, hybrid or baroclinic cyclones, while the zonal separation segregates Gulf of Mexico and Cape Verde storms. The properties of the tracks’ seasonality, intensity, and power dissipation index in each cluster are documented for both configurations. The authors’ results show that, except for the seasonality, the downscaled tracks better capture the observed characteristics of the clusters. The authors also use three different idealized scenarios to examine the possible future changes of tropical cyclone tracks under 1) warming sea surface temperature, 2) increasing carbon dioxide, and 3) a combination of the two. The response to each scenario is highly variable depending on the simulation considered. Finally, the authors examine the role of each cluster in these future changes and find no preponderant contribution of any single cluster over the others.
    Description: Published
    Description: 1333–1361
    Description: 4A. Clima e Oceani
    Description: JCR Journal
    Description: restricted
    Keywords: tropical cyclones ; atlantic basin ; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 2
    facet.materialart.
    Unknown
    Impact of Orbital Parameters and Greenhouse Gas on the Climate of MIS 7 and MIS 5 Glacial Inceptions (2015)
    American Meteorological Society
    Details
    Publication Date: 2021-06-22
    Description: This work explores the impact of orbital parameters and greenhouse gas concentrations on the climate of marine isotope stage (MIS) 7 glacial inception and compares it to that of MIS 5. The authors use a coupled atmosphere-ocean general circulation model to simulate the mean climate state of six time slices at 115, 122, 125, 229, 236, and 239 kyr, representative of a climate evolution from interglacial to glacial inception conditions. The simulations are designed to separate the effects of orbital parameters from those of greenhouse gas (GHG). Their results show that, in all the time slices considered, MIS 7 boreal lands mean annual climate is colder than the MIS 5 one. This difference is explained at 70% by the impact of the MIS 7 GHG. While the impact of GHG over Northern Hemisphere is homogeneous, the difference in temperature between MIS 7 and MIS 5 due to orbital parameters differs regionally and is linked with the Arctic Oscillation. The perennial snow cover is larger in all the MIS 7 experiments compared to MIS 5, as a result of MIS 7 orbital parameters, strengthened by GHG. At regional scale, Eurasia exhibits the strongest response to MIS 7 cold climate with a perennial snow area 3 times larger than in MIS 5 experiments. This suggests that MIS 7 glacial inception is more favorable over this area than over North America. Furthermore, at 239 kyr, the perennial snow covers an area equivalent to that of MIS 5 glacial inception (115 kyr). The authors suggest that MIS 7 glacial inception is more extensive than MIS 5 glacial inception over the high latitudes.
    Description: Italian Ministry of Education, University and Research Ministry for Environment, Land and Sea through the project GEMINA
    Description: Published
    Description: 8918-8933
    Description: 4A. Clima e Oceani
    Description: JCR Journal
    Description: open
    Keywords: Arctic Oscillation ; Teleconnections ; Greenhouse gases ; Glaciation ; Paleoclimate ; 02. Cryosphere::02.03. Ice cores::02.03.05. Paleoclimate
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 3
    facet.materialart.
    Unknown
    South Atlantic paleobathymetry since early Creteceous (2017)
    Springer Nature
    In:  EPIC3Scientific Reports, Springer Nature, 7(11819)
    Details
    Publication Date: 2017-09-24
    Description: We present early Cretaceous to present paleobathymetric reconstructions and quantitative uncertainty estimates for the South Atlantic, offering a strong basis for studies of paleocirculation, paleoclimate and paleobiogeography. Circulation in an initially salty and anoxic ocean, restricted by the topography of the Falkland Plateau, Rio Grande Ridge and Walvis Rise, favoured deposition of thick evaporites in shallow water of the Brazilian-Angolan margins. This ceased as sea oor spreading propagated northwards, opening an equatorial gateway to shallow and intermediate circulation. This gateway, together with subsiding volcano-tectonic barriers would have played a key role in Late Cretaceous climate changes. Later deepening and widening of the South Atlantic, together with gateway opening at Drake Passage would lead, by mid-Miocene (∼15 Ma) to the establishment of modern-style thermohaline circulation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 4
    facet.materialart.
    Unknown
    Evidence of long-term NAO influence on East-Central Europe winter precipitation from a guano-derived δ15N record (2017)
    Springer Nature
    In:  EPIC3Scientific Reports, Springer Nature, 7(1), ISSN: 2045-2322
    Details
    Publication Date: 2017-11-06
    Description: Currently there is a scarcity of paleo-records related to the North Atlantic Oscillation (NAO), particularly in East-Central Europe (ECE). Here we report δ15N analysis of guano from a cave in NW Romania with the intent of reconstructing past variation in ECE hydroclimate and examine NAO impacts on winter precipitation. We argue that the δ15N values of guano indicate that the nitrogen cycle is hydrologically controlled and the δ15N values likely reflect winter precipitation related to nitrogen mineralization prior to the growing season. Drier conditions indicated by δ15N values at AD 1848–1852 and AD 1880–1930 correspond to the positive phase of the NAO. The increased frequency of negative phases of the NAO between AD 1940–1975 is contemporaneous with higher δ15N values (wetter conditions). A 4‰ decrease in δ15N values at the end of the 1970’s corresponds to a strong reduction in precipitation associated with a shift from negative to positive phase of the NAO. Using the relationship between NAO index and δ15N values in guano for the instrumental period, we reconstructed NAO-like phases back to AD 1650. Our results advocate that δ15N values of guano offer a proxy of the NAO conditions in the more distant past, helping assess its predictability.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 5
    facet.materialart.
    Unknown
    A Southern Ocean driver of atmospheric CO2 and Antarctic ice sheets (2017)
    AGU
    In:  EPIC3AGU Fall Meeting 2017, New Orleans, 2017-12-11-2017-12-15New Orleans, AGU
    Details
    Publication Date: 2018-01-07
    Description: A prominent two-step rise in atmospheric CO2 marked the end of the last glacial. The steps coincided with climatic intervals Heinrich Stadial 1 (HS1) and the Younger Dryas (YD). Records of 231Pa/230Th on sediment cores bathed by NADW, revealed a rapid reduction of the Atlantic Meridional Overturning Circulation (AMOC), during these intervals. It was argued that a weakened AMOC would have significantly reduced the efficiency of the biological pump and thus might have contributed to the rise in atmospheric CO2. Despite playing an important role, this process fails to account for the enigmatic drop in atmospheric Δ14C and δ13C during HS1 that marks the first step of the CO2-rise. Increasing CO2-concentrations with a simultaneous drop in their Δ14C, call for the ventilation of an old and 14C-depleted carbon reservoir. In this respect, several studies point to the presence of very old, 14C-depleted deep-waters in the glacial Southern Ocean, which rejuvenated during the last deglaciation. However, the accumulation of 14C-depleted, carbon-rich waters in the deep Southern Ocean requires circulation patterns that significantly differ from todays. Here we present a combined set of 231Pa/230Th-, Rare Earth Element- and XRF-proxy records to understand the evolution of the South Pacific Overturning Circulation (SPOC) over the last 35,000 years. Our reconstructions are based on a transect of five sediment cores from the Southwest Pacific, covering the AAIW as well as the UCDW and LCDW. Our data show that throughout the last glacial the SPOC was significantly weakened. This reduction favored the observed accumulation of 14C-depleted CO2 in Circumpolar Deep Waters (CDW). Parallel to the HS1 increase of atmospheric CO2, the deep circulation picked up its pace and recovered toward the Holocene. This trend is in remarkable agreement with water mass radiocarbon reconstructions from the very same area, as well as with atmospherical changes in CO2, Δ14C and δ13C. Hence, we are confident that the Southern Ocean – represented here by the South Pacific – played the dominant role in the first rise in atmospheric CO2. In addition the observed deglacial SPOC strengthening may have supported the transport of warm CDW onto the shelf areas since the timing of retreating West Antarctic ice sheets is in good agreement with recent reconstructions.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 6
    facet.materialart.
    Unknown
    Rapid changes in anthropogenic carbon storage and ocean acidification in the intermediate layers of the Eurasian Arctic Ocean: 1996-2015 (2018)
    AGU
    In:  EPIC3Global Biogeochemical Cycles, AGU, 32, ISSN: 08866236
    Details
    Publication Date: 2018-06-05
    Description: The extended multiple linear regression (eMLR) technique is used to determine changes in anthropogenic carbon in the intermediate layers of the Eurasian Basin based on occupations from four cruises between 1996 and 2015. The results show a significant increase in basin‐wide anthropogenic carbon storage in the Nansen Basin (0.44‐0.73 ± 0.14 mol C m−2 yr−1) and the Amundsen Basin (0.63‐1.04 ± 0.09 mol C m−2 yr−1). Over the last two decades, inferred changes in ocean acidification (0.020‐0.055 pH units) and calcium carbonate desaturation (0.05‐0.18 units) are pronounced and rapid. These results, together with results from carbonate‐dynamic box model simulations and 129I tracer distribution simulations, suggest that the accumulation of anthropogenic carbon in the intermediate layers of the Eurasian Basin are consistent with increasing concentrations of anthropogenic carbon in source waters of Atlantic origin entering the Arctic Ocean followed by interior transport. The dissimilar distributions of anthropogenic carbon in the interior Nansen and Amundsen Basins are likely due to differences in the lateral ventilation of the intermediate layers by the return flows and ramifications of the boundary current along the topographic boundaries in the Eurasian Basin.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 7
    facet.materialart.
    Unknown
    Along-shelf connectivity and circumpolar gene flow in Antarctic silverfish (Pleuragramma antarctica) (2018)
    Springer Nature
    In:  EPIC3Scientific reports, Springer Nature, 8(17856), pp. 1-16
    Details
    Publication Date: 2019-10-04
    Description: The Antarctic silverfish (Pleuragramma antarctica) is a critically important forage species with a circumpolar distribution and is unique among other notothenioid species for its wholly pelagic life cycle. Previous studies have provided mixed evidence of population structure over regional and circumpolar scales. The aim of the present study was to test the recent population hypothesis for Antarctic silverfish, which emphasizes the interplay between life history and hydrography in shaping connectivity. A total of 1067 individuals were collected over 25 years from different locations on a circumpolar scale. Samples were genotyped at fifteen microsatellites to assess population differentiation and genetic structuring using clustering methods, F-statistics, and hierarchical analysis of variance. A lack of differentiation was found between locations connected by the Antarctic Slope Front Current (ASF), indicative of high levels of gene flow. However, gene flow was significantly reduced at the South Orkney Islands and the western Antarctic Peninsula where the ASF is absent. This pattern of gene flow emphasized the relevance of large-scale circulation as a mechanism for circumpolar connectivity. Chaotic genetic patchiness characterized population structure over time, with varying patterns of differentiation observed between years, accompanied by heterogeneous standard length distributions. The present study supports a more nuanced version of the genetic panmixia hypothesis that reflects physical-biological interactions over the life history.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 8
    facet.materialart.
    Unknown
    Time Variations in Ocean Bottom Pressure from a Few Hours to Many Years: In Situ Data, Numerical Models, and GRACE Satellite Gravimetry (2018)
    AGU
    In:  EPIC3Journal of Geophysical Research: Oceans, AGU, 123(8), pp. 5612-5623, ISSN: 2169-9275
    Details
    Publication Date: 2019-09-04
    Description: In situ ocean bottom pressure (OBP) obtained from 154 different locations irregularly scattered over the globe is carefully processed to isolate signals related to the ocean general circulation and large‐scale sea level changes. Comparison against a global numerical ocean model experiment indicates poor correspondence for periods below 24 hr, possibly related to residual tidal signals and small timing errors in the atmospheric forcing applied to the ocean model. Correspondence increases rapidly for periods between 3 and 10 days, where wind‐driven dynamics are already well understood and consequently well implemented into numerical models. Coherence decreases again for periods around 30 days and longer, where processes not implemented into ocean general circulation models as barystatic sea level changes become more important. Correspondence between in situ data and satellite‐based OBP as obtained from the Gravity Recovery and Climate Experiment (GRACE) German Research Centre for Geosciences RL05a gravity fields critically depends on the postprocessing of Level‐2 Stokes coefficients that also includes the selection of appropriate averaging regions for the GRACE‐based mass anomalies. The assessment of other available GRACE Level‐2 products indicates even better fit of more recent solutions as ITSG‐Grace2016 and the Center for Space Research and Jet Propulsion Laboratory RL05 mascons. In view of the strong high‐frequency component of OBP, however, a higher temporal resolution of the oceanic GRACE products would be rather advantageous.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 9
    facet.materialart.
    Unknown
    Quantifying methane ebullition from northern lakes with space-borne synthetic aperture radar (SAR) (2018)
    AGU
    In:  EPIC3AGU Fall Meeting 2018, Washington, D.C., USA, 2018-12-10-2018-12-14Washington, D.C., USA, AGU
    Details
    Publication Date: 2019-12-24
    Description: Lakes in the northern permafrost region are a significant source of atmospheric methane (CH4), a potent greenhouse gas, yet large uncertainties exist in quantifying lake-source CH4. In thermokarst (thaw) lakes, the dominant pathway of CH4, ebullition (bubbling), is sporadic and spatially irregular. These lakes are also generally remote and difficult to access, resulting in challenging and costly field measurements. Scaling up field measurements from a few study lakes to regional and pan-Arctic scales relies on the assumption that the sampled lakes are a fair representation of all lakes across a landscape, which is not always the case. We present an innovative new method of quantifying lake-source CH4 using space-borne synthetic aperture radar (SAR), an instrument which can image at night, through clouds and dry snow, valuable attributes for Arctic remote sensing. Our recent work using satellite-based SAR data showed a significant correlation between polarimetric L-band SAR backscatter from lake ice and field-measured ebullition bubbles: L-band SAR backscatter intensity increases with the amount of ebullition bubbles trapped by early winter lake ice. We developed a regionally robust empirical model based on this correlation to quantify ebullition across surfaces of over 5,000 individual Alaskan lakes in satellite SAR scenes. We produced SAR-based ebullition fluxes from each lake across the landscape and created CH4 maps for five sub-regions in Alaska. Our SAR-based lake-source CH4 fluxes compare favorably with airborne CH4 measurements on the Barrow Peninsula and Atqasuk regions, and with scaled-up field measurements. We examine how our SAR remote sensing application can 1) improve selection of study lakes for field work, 2) provide regional estimates of CH4 ebullition from lakes in remote areas where field work is limited, 3) improve lake-size vs. flux relationships for upscaling field measurements and 4) shed light on the discrepancy of top-down vs. bottom-up CH4 flux estimates in the Arctic. This new approach to estimate lake-source CH4 from ebullition offers a unique opportunity to improve knowledge about CH4 fluxes for seasonally ice-covered lakes globally.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 10
    facet.materialart.
    Unknown
    Lateral Thermokarst Lake Dynamics: A Remote Sensing Based Analysis of Spatial Variabilities and Erosion Processes (2019)
    AGU
    In:  EPIC3AGU Fall Meeting 2019, San Francisco, USA, 2019-12-09-2019-12-13San Francisco, USA, AGU
    Details
    Publication Date: 2020-02-17
    Description: Thermokarst lakes are one of the most abundant landforms in periglacial landscapes. They develop in regions underlain by permafrost as a consequence of soil subsidence triggered by the melting of excess ground ice. As a result of further permafrost degradation and shoreline erosion, thermokarst lakes increase in size, expanding vertically and laterally. This growth process has strong impacts on local to regional hydrological networks and ecological functions of the surrounding landscape. Previous research on the lateral growth of thermokarst lakes usually focused on decadal time scales which results in averaged expansion rates. These averages mask the temporal and spatial variations of lateral thermokarst expansion that occur over shorter time periods of only a few years. The short-term variability results from complex interactions between local erosion processes and meteorological and permafrost conditions. The aim of our study is to quantify these short-term changes of lake shorelines to provide a better understanding of permafrost landscape processes using multi-temporal high-resolution satellite imagery. The images are in the visible and near-infrared spectrum with a resolution of 0.3 to 0.7 m. They cover the period from 2006 to 2017 with acquisitions every 2 to 4 years. In order to map the lake shoreline changes we developed a fully-automated, open-source workflow for analyzing the changes of waterbodies larger than 1000 m². First, all necessary pre-processing steps are implemented such as pansharpening and smoothing of any speckle over waterbodies. Then, the normalized difference water index (NDWI) is applied to extract waterbodies from the imagery and derive their shoreline geometry. After filtering for potentially misclassified elements that originate from infrastructure, shoreline movement rates are calculated using a nearest point analysis. The workflow is independent of scale, image spatial resolution, and waterbody geometry. Preliminary findings demonstrate that the approach provides reliable shoreline recognition for every time step in the different study areas even under difficult light conditions. Changes can be detected on a sub-meter scale. Finally, we discuss the influence of the waterbody’s size and geometry on the shoreline change processes.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...