ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Wiley  (249,927)
  • American Geophysical Union  (49,576)
  • Annual Reviews
  • PANGAEA
  • 2015-2019  (270,374)
  • 1980-1984  (66,327)
  • 1955-1959  (14,833)
  • 1940-1944  (7,055)
Collection
Keywords
Language
Years
Year
  • 1
    Publication Date: 2020-12-14
    Description: Explosive volcanic eruptions are defined as the violent ejection of gas and hot fragments from a vent in the Earth's crust. Knowledge of ejection velocity is crucial for understanding and modeling relevant physical processes of an eruption, and yet direct measurements are still a difficult task with largely variable results. Here we apply pioneering high-speed imaging to measure the ejection velocity of pyroclasts from Strombolian explosive eruptions with an unparalleled temporal resolution. Measured supersonic velocities, up to 405 m/s, are twice higher than previously reported for such eruptions. Individual Strombolian explosions include multiple, sub-second-lasting ejection pulses characterized by an exponential decay of velocity. When fitted with an empirical model from shock-tube experiments literature, this decay allows constraining the length of the pressurized gas pockets responsible for the ejection pulses. These results directly impact eruption modeling and related hazard assessment, as well as the interpretation of geophysical signals from monitoring networks.
    Description: INGV-DPC “V2” and “Paroxysm”, FIRB-MIUR “Research and Development of New Technologies for Protection and Defense of Territory from Natural Risks”, and FP7-PEOPLE-IEF-2008 – 235328 Projects
    Description: Published
    Description: L02301
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: open
    Keywords: strombolian ; ejection velocity ; explosive eruption ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2021-02-10
    Description: Continuous gravity data collected near the summit eruptive vent at Kīlauea Volcano, Hawaiʻi, during 2011–2015 show a strong correlation with summit-area surface deformation and the level of the lava lake within the vent over periods of days to weeks, suggesting that changes in gravity reflect variations in volcanic activity. Joint analysis of gravity and lava level time series data indicates that over the entire time period studied, the average density of the lava within the upper tens to hundreds of meters of the summit eruptive vent remained low—approximately 1000–1500 kg/m^3. The ratio of gravity change (adjusted for Earth tides and instrumental drift) to lava level change measured over 15 day windows rose gradually over the course of 2011–2015, probably reflecting either (1) a small increase in the density of lava within the eruptive vent or (2) an increase in the volume of lava within the vent due to gradual vent enlargement. Superimposed on the overall time series were transient spikes of mass change associated with inflation and deflation of Kīlauea’s summit and coincident changes in lava level. The unexpectedly strong mass variations during these episodes suggest magma flux to and from the shallow magmatic system without commensurate deformation, perhaps indicating magma accumulation within, and withdrawal from, void space—a process that might not otherwise be apparent from lava level and deformation data alone. Continuous gravity data thus provide unique insights into magmatic processes, arguing for continued application of the method at other frequently active volcanoes.
    Description: Published
    Description: 5477–5492
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Kīlauea Volcano; gravity changes; lava lake; volcano monitoring ; 04. Solid Earth::04.02. Exploration geophysics::04.02.02. Gravity methods ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2021-02-10
    Description: A network of four borehole dilatometers has been installed on Etna in two successive phases (2010–2011 and 2014). The borehole dilatometers are installed in holes drilled at depths usually greater than 100 m, and they measure the volumetric strain of the surrounding rock with a nominal precision up to 10^-11 in a wide frequency range (10^-7–25 Hz). Here we describe the characteristics of the network and the results of the in situ calibrations obtained after the installations by different methods. We illustrate short-term strain changes recorded during several lava fountains erupted by Etna during 2011–2013, and we also show signal changes recorded at all four stations during the lava fountain on 28 December 2014. Analytical and numerical computations constrained the eruptions source depth and also its volume change that is related to the magma volume emitted. Finally, we show the potential of the signal in the medium term to reveal strain changes related to different phases of the volcanic activity.
    Description: Published
    Description: 4655–4669
    Description: 1IT. Reti di monitoraggio e Osservazioni
    Description: JCR Journal
    Description: restricted
    Keywords: Etna volcano ; borehole strainmeters ; strain ; eruptions and lava fountains ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2021-03-01
    Description: A new period of eruptive activity started at Turrialba volcano, Costa Rica, in 2010 after almost 150 years of quiescence. This activity has been characterized by sporadic explosions whose frequency clearly increased since October 2014. This study aimed to identify the mechanisms that triggered the resumption of this eruptive activity and characterize the evolution of the phenomena over the past 2 years. We integrate 3He/4He data available on fumarole gases collected in the summit area of Turrialba between 1999 and 2011 with new measurements made on samples collected between September 2014 and February 2016. The results of a petrological investigation of the products that erupted between October 2014 and May 2015 are also presented. We infer that the resumption of eruptive activity in 2010 was triggered by a replenishment of the plumbing system of Turrialba by a new batch of magma. This is supported by the increase in 3He/4He values observed since 2005 at the crater fumaroles and by comparable high values in September 2014, just before the onset of the new eruptive phase. The presence of a number of fresh and juvenile glassy shards in the erupted products increased between October 2014 and May 2015, suggesting the involvement of new magma with a composition similar to that erupted in 1864–1866. We conclude that the increase in 3He/4He at the summit fumaroles since October 2015 represents strong evidence of a new phase of magma replenishment, which implies that the level of activity remains high at the volcano.
    Description: Published
    Description: 3V. Proprietà dei magmi e dei prodotti vulcanici
    Description: 4V. Dinamica dei processi pre-eruttivi
    Description: 5V. Dinamica dei processi eruttivi e post-eruttivi
    Description: JCR Journal
    Keywords: Turrialba volcano ; eruptive activity ; 3He/4He ; fumarole gases ; glassy shards ; juvenile component ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2021-03-09
    Description: Mixed‐mode fluid‐filled cracks represent a common means of fluid transport within the Earth's crust. They often show complex propagation paths which may be due to interaction with crustal heterogeneities or heterogeneous crustal stress. Previous experimental and numerical studies focus on the interplay between fluid over-pressure and external stress but neglect the effect of other crack parameters. In this study, we address the role of crack length on the propagation paths in the presence of an external heterogeneous stress field. We make use of numerical simulations of magmatic dike and hydrofracture propagation, carried out using a two‐dimensional boundary element model, and analogue experiments of air‐filled crack propagation into a transparent gelatin block. We use a 3‐D finite element model to compute the stress field acting within the gelatin block and perform a quantitative comparison between 2‐D numerical simulations and experiments. We show that, given the same ratio between external stress and fluid pressure, longer fluid‐filled cracks are less sensitive to the background stress, and we quantify this effect on fluid‐filled crack paths. Combining the magnitude of the external stress, the fluid pressure, and the crack length, we define a new parameter, which characterizes two end member scenarios for the propagation path of a fluid‐filled fracture. Our results have important implications for volcanological studies which aim to address the problem of complex trajectories of magmatic dikes (i.e., to forecast scenarios of new vents opening at volcanoes) but also have implications for studies that address the growth and propagation of natural and induced hydrofractures.
    Description: Published
    Description: 2064–2081
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Keywords: Magmatic dykes ; hydrofractures ; Numerical symulations ; Analogue experiments ; 04.08. Volcanology ; 05.05. Mathematical geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2020-12-15
    Description: We report on a systematic record of SO2 flux emissions from individual vents of Etna volcano (Sicily), which we obtained using a permanent UV camera network. Observations were carried out in summer 2014, a period encompassing two eruptive episodes of the New South East Crater (NSEC) and a fissure-fed eruption in the upper Valle del Bove. We demonstrate that our vent-resolved SO2 flux time series allow capturing shifts in activity from one vent to another and contribute to our understanding of Etna’s shallowplumbingsystemstructure.We findthatthe fissureeruptioncontributed~50,000tofSO2 or~30%of the SO2 emitted by the volcano during the 5 July to 10 August eruptive interval. Activity from this eruptive ventgraduallyvanishedon10August,markingaswitchofdegassingtowardtheNSEC.Onsetofdegassingat the NSEC was a precursory to explosive paroxysmal activity on 11–15 August.
    Description: Published
    Description: 7511-7519
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Records of SO2 flux emissions from Etna’sindividualventsallowcapturing shifts in volcanic activity ; Vent-resolved SO2 flux time series provide constraints on geometry of the shallow plumbing system ; Vent-resolved SO2 flux time series demonstrate SO2 flux increase precursory to paroxysmal (lava fountaining) activity ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2021-02-10
    Description: Annual January/July midlatitude daytime asymmetry in monthly median NmF2 and model thermospheric parameters has been considered during deep solar minimum, (2008–2009), when solar and geomagnetic activities were at the lowest level, to analyze the background effect due to the Sun-Earth minimum distance, perihelion, in the vicinity of the December solstice. Averaged over 10 midlatitude station pairs, the NmF2 asymmetry was found to be ≈1.23, while the average asymmetry for the annual component in NmF2 variations is ≈1.17. Annual asymmetry in monthly median neutral composition and temperature predicted by Mass Spectrometer Incoherent Scatter 86 (MSIS86) and MSISE00 thermospheric models along with the 7% increase in solar EUV flux in the vicinity of the December solstice is sufficient to explain the observed annual asymmetry in NmF2. A hierarchy of aeronomic parameters responsible for the observed asymmetry in NmF2 has been established: the main contributor is atomic oxygen—about 50% of the total effect, [N2] contributes around 35% strongly compensating the [O] contribution, and solar EUV and Tn provide 〈10% each. The zonal mean annual asymmetry in MSIS86 atomic oxygen column density was shown to be 1.18 at low and middle latitudes, and this is close to the estimated asymmetry for the annual component in NmF2 variations. The earlier proposed mechanism of the December anomaly is considered as a plausible one to explain the 1.18 January/July asymmetry in the atomic oxygen variations and consequently the NmF2 annual daytime asymmetry at middle latitudes under the deep solar minimum.
    Description: Published
    Description: 1341-1354
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Description: restricted
    Keywords: december anomaly ; 01. Atmosphere::01.02. Ionosphere::01.02.01. Ion chemistry and composition
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2021-06-25
    Description: The geological record at rifts and margins worldwide often reveals considerable along-strike variations in volumes of extruded and intruded igneous rocks. These variations may be the result of asthenospheric heterogeneity, variations in rate, and timing of extension; alternatively, preexisting plate architecture and/or the evolving kinematics of extension during breakup may exert first-order control on magmatism. The Main Ethiopian Rift (MER) in East Africa provides an excellent opportunity to address this dichotomy: it exposes, along strike, several sectors of asynchronous rift development from continental rifting in the south to incipient oceanic spreading in the north. Here we perform studies of volcanic cone density and rift obliquity along strike in the MER. By synthesizing these new data in light of existing geophysical, geochemical, and petrological constraints on magma generation and emplacement, we are able to discriminate between tectonic and mantle geodynamic controls on the geological record of a newly forming magmatic rifted margin. The timing of rift sector development, the three-dimensional focusing of melt, and the ponding of plume material where the rift dramatically narrows each influence igneous intrusion and volcanism along the MER. However, rifting obliquity plays an important role in localizing intrusion into the crust beneath en echelon volcanic segments. Along-strike variations in volumes and types of igneous rocks found at rifted margins thus likely carry information about the development of strain during rifting, as well as the physical state of the convecting mantle at the time of breakup.
    Description: Published
    Description: 467-477
    Description: 1T. Geodinamica e interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: Variationsinmeltproductioncausedby asynchronous rift sector development • Where the rift narrows, ponding of plume material may enhance melting • Three-dimensional migration of melt along the LAB focuses magma supply ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2021-01-04
    Description: We present a neotectonic model of ongoing lithosphere deformation and a corresponding estimate of long-term shallow seismicity across the Africa-Eurasia plate boundary, including the eastern Atlantic, Mediterranean region, and continental Europe. GPS and stress data are absent or inadequate for the part of the study area covered by water. Thus, we opt for a dynamic model based on the stress-equilibrium equation; this approach allows us to estimate the long-term behavior of the lithosphere (given certain assumptions about its structure and physics) for both land and sea areas. We first update the existing plate model by adding five quasi-rigid plates (the Ionian Sea, Adria, Northern Greece, Central Greece, and Marmara) to constrain the deformation pattern of the study area. We use the most recent datasets to estimate the lithospheric structure. The models are evaluated in comparison with updated datasets of geodetic velocities and the most compressive horizontal principal stress azimuths. We find that the side and basal strengths drive the present-day motion of the Adria and Aegean Sea plates, whereas lithostatic pressure plays a key role in driving Anatolia. These findings provide new insights into the neotectonics of the greater Mediterranean region. Finally, the preferred model is used to estimate long-term shallow seismicity, which we retrospectively test against historical seismicity. As an alternative to reliance on incomplete geologic data or historical seismic catalogs, these neotectonic models help to forecast long-term seismicity, although requiring additional tuning before seismicity rates are used for seismic hazard purposes.
    Description: Published
    Description: 5311–5342
    Description: 1T. Geodinamica e interno della Terra
    Description: 2T. Tettonica attiva
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: open
    Keywords: Tectonics ; Earthquake rates ; 04. Solid Earth::04.02. Exploration geophysics::04.02.03. Heat flow ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability ; 04. Solid Earth::04.07. Tectonophysics::04.07.01. Continents ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.04. Plate boundaries, motion, and tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2021-06-25
    Description: Airborne and ground-based differential optical absorption spectroscopy observations have been carried out at the volcano Nyiragongo (Democratic Republic of Congo) tomeasure SO2 and bromine monoxide (BrO) in the plume inMarch 2004 and June 2007, respectively. Additionally filter pack andmulticomponent gas analyzer system (Multi-GAS)measurements were carried out in June 2007. Ourmeasurements provide valuable information on the chemical composition of the volcanic plume emitted fromthe lava lake of Nyiragongo. The main interest of this study has been to investigate for the first time the bromine emission flux of Nyiragongo (a rift volcano) and the BrO formation in its volcanic plume. Measurement data and results from a numerical model of the evolution of BrO in Nyiragongo volcanic plume are compared with earlier studies of the volcanic plume of Etna (Italy). Even though the bromine flux from Nyiragongo (2.6 t/d) is slightly greater than that from Etna (1.9 t/d), the BrO/SO2 ratio (maximum 7 × 10 5) is smaller than in the plume of Etna (maximum 2.1 × 10 4). A one-dimensional photochemical model to investigate halogen chemistry in the volcanic plumes of Etna and Nyiragongo was initialized using data from Multi-GAS and filter pack measurements. Model runs showed that the differences in the composition of volcanic volatiles led to a smaller fraction of total bromine being present as BrO in the Nyiragongo plume and to a smaller BrO/SO2 ratio.
    Description: Published
    Description: 277-291
    Description: 4V. Vulcani e ambiente
    Description: JCR Journal
    Description: restricted
    Keywords: Intraplate volcano Nyiragongo is bromine rich although chlorine poor ; BrO/Br in volcanic plumes depends on initial plume composition ; Determination of Nyiragongo chlorine, bromine, sulfur emission strength ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Publication Date: 2021-07-14
    Description: Archaeological exavations,undertaken since 2004 for the construction of the new Naples subway
    Description: Published
    Description: 542-557
    Description: 1V. Storia eruttiva
    Description: JCR Journal
    Keywords: A.D.79 eruption ; compositional data analysis ; geoarchaeology ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2021-07-13
    Description: Mount Etna volcano is subject to transient magmatic intrusions and flank movement. The east flank of the edifice, in particular, is moving eastward and is dissected by the Timpe Fault System. The relationship of this eastward motion with intrusions and tectonic fault motion, however, remains poorly constrained. Here we explore this relationship by using analogue experiments that are designed to simulate magmatic rift intrusion, flank movement, and fault activity before, during, and after a magmatic intrusion episode. Using particle image velocimetry allows for a precise temporal and spatial analysis of the development and activity of fault systems. The results show that the occurrence of rift intrusion episodes has a direct effect on fault activity. In such a situation, fault activitymay occur or may be hindered, depending on the interplay of fault displacement and flank acceleration in response to dike intrusion. Our results demonstrate that a complex interplaymay exist between an active tectonic fault system and magmatically induced flank instability. Episodes of magmatic intrusion change the intensity pattern of horizontal flank displacements andmay hinder or activate associated faults. We further compare our results with the GPS data of the Mount Etna 2001 eruption and intrusion. We find that syneruptive displacement rates at the Timpe Fault System have differed from the preeruptive or posteruptive periods, which shows a good agreement of both the experimental and the GPS data. Therefore, understanding the flank instability and flank stability at Mount Etna requires consideration of both tectonic and magmatic forcing.
    Description: Published
    Description: 5356-5368
    Description: 1V. Storia e struttura dei sistemi vulcanici
    Description: JCR Journal
    Description: restricted
    Keywords: analogue models ; strain ; stress ; eruption ; flank dynamics ; GPS ; faults ; Etna ; 04. Solid Earth::04.03. Geodesy::04.03.08. Theory and Models
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Publication Date: 2020-12-15
    Description: We have analyzed a focal mechanism data set for Mount Vesuvius, consisting of 197 focal mechanisms of events recorded from 1999 to 2012. Using different approaches and a comparison between observations and numerical models, we have determined the spatial variations in the stress field beneath the volcano. The main results highlight the presence of two seismogenic volumes characterized by markedly different stress patterns. The two volumes are separated by a layer where the seismic strain release shows a significant decrease. Previous studies postulated the existence, at about the same depth, of a ductile layer allowing the spreading of the Mount Vesuvius edifice. We interpreted the difference in the stress pattern within the two volumes as the effect of a mechanical decoupling caused by the aforementioned ductile layer. The stress pattern in the top volume is dominated by a reverse faulting style, which agrees with the hypothesis of a seismicity driven by the spreading process. This agrees also with the persistent character of the seismicity located within this volume. Conversely, the stress field determined for the deep volume is consistent with a background regional field locally perturbed by the effects of the topography and of heterogeneities in the volcanic structure. Since the seismicity of the deep volume shows an intermittent behavior and has shown to be linked to geochemical variations in the fumaroles of the volcano, we hypothesize that it results from the effect of fluid injection episodes, possibly of magmatic origin, perturbing the pore pressure within the hydrothermal system.
    Description: Published
    Description: 1181–1199
    Description: 4T. Fisica dei terremoti e scenari cosismici
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: vesuvius ; stress inversion ; focal mechanisms ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Publication Date: 2020-12-15
    Description: In thismanuscript we present a new interpretation of the seismic series that accompanied eruptive activity off the coast of El Hierro, Canary Islands, during 2011–2013. We estimated temporal variations of the Gutenberg-Richter b value throughout the period of analysis, and performed high-precision relocations of the preeruptive and syneruptive seismicity using a realistic 3-D velocity model. Our results suggest that eruptive activity and the accompanying seismicity were caused by repeated injections of magma from the mantle into the lower crust. These magma pulses occurred within a small and well-defined volume resulting in the emplacement of fresh magma along the crust-mantle boundary underneath El Hierro. We analyzed the distribution of earthquake hypocenters in time and space in order to assess seismic diffusivity in the lower crust. Our results suggest that very high earthquake rates underneath El Hierro represent the response of a stable lower crust to stress perturbations with pulsatory character, linked to the injection of magma from the mantle. Magma input from depth caused large stress perturbations to propagate into the lower crust generating energetic seismic swarms. The absence of any preferential alignment in the spatial pattern of seismicity reinforces our hypothesis that stress perturbation and related seismicity, had diffusive character. We conclude that the temporal and spatial evolution of seismicity was neither tracking the path of magma migration nor it defines the boundaries of magma storage volumes such as a midcrustal sill. Our conceptual model considers pulsatorymagma injection fromthe uppermantle and its propagation along the Moho.We suggest, within this framework, that the spatial and temporal distributions of earthquake hypocenters reflect hydraulic fracturing processes associated with stress propagation due to magma movement.
    Description: Published
    Description: 7749–7770
    Description: 1T. Geodinamica e interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: b value, relocation, Hydraulic fracturing, Magma influx ; 05. General::05.02. Data dissemination::05.02.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2021-01-25
    Description: Tsunami deposits present an important archive for understanding tsunami histories and dynamics. Most research in this field has focused on onshore preserved remains, while the offshore deposits have received less attention. In 2009, during a coring campaign with theItalian Navy Magnaghi, four 1 m long gravity cores (MG cores) were sampled from the northern part of Augusta Bay, along a transect in 60 to 110 m water depth. These cores were taken in the same area where a core (MS06) was collected in 2007 about 2.3 km offshore Augusta at a water depth of 72 m below sea level. Core MS06 consisted of a 6.7 m long sequence that included 12 anomalous intervals interpreted as the primary effect of tsunami backwash waves in the last 4500 years. In this study, tsunami deposits were identified, based on sedimentology and displaced benthic foraminifera (as for core MS06) reinforced by X-ray fluorescence data. Two erosional surfaces (L1 and L2) were recognized coupled with grain size increase, abundant Posidonia oceanica seagrass remains and a significant amount of Nubecularia lucifuga, an epiphytic sessile benthic foraminifera considered to be transported from the inner shelf. The occurrence of Ti/Ca and Ti/Sr increments, coinciding with peaks in organic matter (Mo inc/coh) suggests terrestrial run-off coupled with an input of organic matter. The L1 and L2 horizons were attributed to two distinct historical tsunamis (AD 1542 and AD 1693) by indirect age-estimation methods using 210Pb profiles and the comparison of Volume Magnetic Susceptibility data between MG cores and MS06 cores. One most recent bioturbated horizon (Bh), despite not matching the above listed interpretative features, recorded an important palaeoenvironmental change that may correspond to the AD 1908 tsunami. These findings reinforce the value of offshore sediment records as an underutilized resource for the identification of past tsunamis.
    Description: Published
    Description: 1553-1576
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Eastern Sicily ; tsunami ; foraminifera ; sedimentology ; XRF core scanning ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2021-02-10
    Description: Moore (1964) in a letter published in Nature reported disturbances in geomagnetic field data prior to the 27 March 1964 Alaska earthquake. After the publication of this report, many papers have shown magnetic changes preceding earthquakes. However, a causal relationship between preearthquake magnetic changes and impending earthquakes has never been demonstrated. As a consequence, after 50 years, magnetic disturbances in the geomagnetic field are still candidate precursory phenomena. Some researchers consider the investigation of ultra low frequency (ULF: 0.001–10 Hz) magnetic data the correct approach for identifying precursory signatures of earthquakes. Other researchers, instead, have recently reviewed many published ULF magnetic changes that preceded earthquakes and have shown that these are not actual precursors. The recent studies by Currie and Waters (2014) and Han et al. (2014) aim to provide relevant new findings in the search for ULF magnetic precursory signals. However, in order to contribute to science, alleged precursors must be shown to be valid and reproducible by objective testing. Here we will briefly discuss the state of the art in the search for ULF magnetic precursors, paying special attention to the recent findings of Currie and Waters (2014) and Han et al. (2014). We do not see in these two reports significant evidence that may support the observation of precursory signatures of earthquakes in ULF magnetic records.
    Description: Published
    Description: 10289–10304
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Geomagnetic field ; Magnetic anomalies ; Earthquake precursors ; 01. Atmosphere::01.03. Magnetosphere::01.03.03. Magnetospheric physics ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2021-04-07
    Description: Integrating geodetic, seismic, and petrological data for a recent eruptive episode at Mount Etna has enabled us to define the history of magma storage and transfer within the multilevel structure of the volcano, providing spatial and temporal constraints for magma movements before the eruption. Geodetic data related to the July–August 2014 activity provide evidence of a magma reservoir at ~4 km below sea level. This reservoir pressurized from late March 2014 and fed magmas that were then erupted from vents on the lower eastern flank of North-East Crater (NEC) and at New South-East Crater (NSEC) summit crater during the July eruptive activity. Magma drainage caused its depressurization since mid-July. Textural and microanalytical data obtained from plagioclase crystals indicate similar disequilibrium textures and compositions at the cores in lavas erupted at the base of NEC and NSEC, suggesting comparable deep histories of evolution and ascent. Conversely, the compositional differences observed at the crystal rims have been associated to distinct degassing styles during storage in a shallow magma reservoir. Seismic data have constrained depth for a shallow part of the plumbing system at 1–2 km above sea level. Timescales of magma storage and transfer have also been calculated through diffusion modeling of zoning in olivine crystals of the two systems. Our data reveal a common deep history of magmas from the two systems, which is consistent with a recharging phase by more mafic magma between late March and early June 2014. Later, the magma continued its crystallization under distinct chemical and physical conditions at shallower levels.
    Description: The petrological part of this study was supported by the FIR 2014 research grant to Marco Viccaro from the University of Catania (Italy), grant number 2F119B, title of the project “Dynamics of evolution, ascent and emplacement of basic magmas: case-studies from eruptive manifestations of Eastern Sicily”.
    Description: Published
    Description: 5659–5678
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 3V. Dinamiche e scenari eruttivi
    Description: JCR Journal
    Description: restricted
    Keywords: Petrology ; eruption ; GPS ; volcano seismology ; Etna ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.07. Rock geochemistry ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2021-05-17
    Description: Here we present the results of the inversion of a new geodetic data set covering the 2012 Emilia seismic sequence and the following 1 year of postseismic deformation. Modeling of the geodetic data together with the use of a catalog of 3-D relocated aftershocks allows us to constrain the rupture geometries and the coseismic and postseismic slip distributions for the two main events (Mw 6.1 and 6.0) of the sequence and to explore how these thrust events have interacted with each other. Dislocation modeling reveals that the first event ruptured a slip patch located in the center of the Middle Ferrara thrust with up to 1 m of reverse slip. The modeling of the second event, located about 15 km to the southwest, indicates a main patch with up to 60 cm of slip initiated in the deeper and flatter portion of the Mirandola thrust and progressively propagated postseismically toward the top section of the rupture plane, where most of the aftershocks and afterslip occurred. Our results also indicate that between the two main events, a third thrust segment was activated releasing a pulse of aseismic slip equivalent to a Mw 5.8 event. Coulomb stress changes suggest that the aseismic event was likely triggered by the preceding main shock and that the aseismic slip event probably brought the second fault closer to failure. Our findings show significant correlations between static stress changes and seismicity and suggest that stress interaction between earthquakes plays a significant role among continental en echelon thrusts.
    Description: Published
    Description: 4742–4766
    Description: 1T. Deformazione crostale attiva
    Description: 2T. Sorgente Sismica
    Description: 3T. Storia Sismica
    Description: JCR Journal
    Keywords: continental tectonics ; source geometry ; geodetic modeling ; coulomb stress ; 04. Solid Earth
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Publication Date: 2021-06-16
    Description: Earthquakes occurring close to hydrocarbon fields under production are often under critical view of being induced or triggered. However, clear and testable rules to discriminate the different events have rarely been developed and tested. The unresolved scientific problem may lead to lengthy public disputes with unpredictable impact on the local acceptance of the exploitation and field operations. We propose a quantitative approach to discriminate induced, triggered and natural earthquakes, which is based on testable input parameters. Maxima of occurrence probabilities are compared for the cases under question, and a single probability of being triggered or induced is reported. The uncertainties of earthquake location and other input parameters are considered in terms of the integration over probability density functions (pdf). The probability that events have been human-triggered/induced is derived from the modeling of Coulomb stress changes and a rate and state dependent seismicity model. In our case a 3D boundary element method has been adapted for the nuclei of strain approach to estimate the stress changes outside the reservoir, which are related to pore pressure changes in the field formation. The predicted rate of natural earthquakes is either derived from the background seismicity or, in case of rare events, from an estimate of the tectonic stress rate. Instrumentally derived, seismological information on the event location, source mechanism and the size of the rupture plane is of advantage for the method. If the rupture plane has been estimated, the discrimination between induced or only triggered events is theoretically possible if probability functions are convolved with a rupture fault filter. We apply the approach to three recent main-shock events: (1) the Mw 4.3 Ekofisk 2001, North Sea earthquake close to the Ekofisk oil field, the 2004 Mw 4.4 Rotenburg, Northern Germany earthquake in the vicinity of the Söhlingen gas field, and the Mw 6.1 Emilia 2012, Northern Italy earthquake in the vicinity of a hydrocarbon reservoir. The three test cases cover the complete range of possible causes: clearly “human-induced”, “not even human-triggered” and a third case in-between both extremes.
    Description: Published
    Description: 2491–2509
    Description: 6T. Sismicità indotta e caratterizzazione sismica dei sistemi naturali
    Description: JCR Journal
    Description: restricted
    Keywords: Induced seismicity ; probabilistic discrimination ; hydrocarbon field ; triggered earthquake ; seismic hazard ; earthquake ; 04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Publication Date: 2021-06-16
    Description: This study performed the first assessment of the volcanic gas output from the Central Volcanic Zone (CVZ) of northern Chile. We present the fluxes and compositions of volcanic gases (H2O, CO2, H2, HCl, HF, and HBr) from five of the most actively degassing volcanoes in this region—Láscar, Lastarria, Putana, Ollagüe, and San Pedro—obtained during field campaigns in 2012 and 2013. The inferred gas plume compositions for Láscar and Lastarria (CO2/Stot = 0.9–2.2; Stot/HCl = 1.4–3.4) are similar to those obtained in the Southern Volcanic Zone of Chile, suggesting uniform magmatic gas fingerprint throughout the Chilean arc. Combining these compositions with our own UV spectroscopy measurements of the SO2 output (summing to ~1800 t d 1 for the CVZ), we calculate a cumulative CO2 output of 1743–1988 t d 1 and a total volatiles output of 〉20,200 t d 1. 1.
    Description: Published
    Description: 4961-4969
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Gas output from the Central Volcanic Zone ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Publication Date: 2021-06-25
    Description: Beside anthropogenic influences, mercury in the environment can also be of natural origin. Among geologic sources, volcanic activity has been of main interest so far. Modern estimations of global natural emissions are between 2000 and 5200 tonnes per year. However, these estimates are very uncertain, thus more detailed and systematic research on natural sources of mercury is necessary. Tectonic activity is connected to certain phenomena such as degassing of Hg and other gases from active faults, geothermal activity, volcanoes, etc., especially on tectonic plate margins. Elemental mercury concentrations in air, soil gases and fluxes, as well as its speciation, in connection to tectonic activity, were studied in different environments such are karst cave (Postojna Cave), active volcano areas (Mt. Etna, Italy), and active tectonic areas in the Mediterranean Basin on Africa-Adriatic tectonic plate margin. Postojna Cave is characterized by elevated Hg (up to 150 ng m-3) air concentrations at certain areas in vicinity of active faults; however the concentrations showed also strong seasonal variations. Mt. Etna on Sicily is the largest and most active Mediterranean volcano. Concentrations of mercury in air in the vicinity of the volcano are relatively high (between 4 and 30 ng m-3) and rise towards the summit crater (65 to 130 ng m-3). Concentrations in sulphatare and fumaroles gases on the summit of the volcano can reach very high values (even up to 60 μg m-3). The Mediterranean Basin is characterized by strong tectonic activity as a consequence of subduction of African plate under the Eurasian plate. A possible source of DGM (dissolved gaseous mercury in sea water) in deeper and bottom waters could be intensive tectonic activity of the seafloor, since higher concentrations and portions of DGM were found near the bottom at locations with strong tectonic activity (Alboran Sea, Strait of Sicily, Tyrrhenian Sea, Ionian Sea). Distribution of different mercury species in sediment and water of the Mediterranean Sea showed that the main source of mercury is geotectonic activity and its accompanying phenomena.
    Description: Published
    Description: San Francisco
    Description: 6A. Monitoraggio ambientale, sicurezza e territorio
    Description: restricted
    Keywords: Mercury ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Publication Date: 2021-06-25
    Description: The transition from mechanical thinning toward focused magmatic intrusion during continental rifting is poorly constrained; the tectonically active Main Ethiopian Rift (MER) provides an ideal study locale to address this issue. The presence of linear magmatic-tectonic belts in the relatively immature central MER may indicate that the transition from mechanical to magmatic rifting is more spatially distributed and temporally protracted than has previously been assumed. Here we examine lava geochemistry and vent distribution of a Pliocene-Quaternary linear magmatic chain along the western margin of the central MER—the Akaki Magmatic Zone. Our results show limited variability in parental magma that evolve in a complex polybaric fractionation system that has not changed significantly over the past 3 Ma. Our results suggest the following: (1) channeling of plume material and the localization of shear- or topography-induced porosity modulates melt intrusion into the continental lithosphere. (2) Pre-existing lithospheric structures may act as catalysts for intrusion of magmas into the lithospheric mantle. (3) The midcrustal to upper crustal strain regime dictates the surface orientation of volcanic vents. Therefore, although linear magmatic belts like those in the central MER may young progressively toward the rift axis and superficially resemble oceanic style magmatism, they actually represent prebreakup magmatism on continental crust. The oldest linear magmatic belts observed seismically and magnetically at the edge of the ocean basins thus may not, as is often assumed, actually mark the onset of seafloor spreading.
    Description: Published
    Description: 875–897
    Description: 1T. Geodinamica e interno della Terra
    Description: JCR Journal
    Description: restricted
    Keywords: Precambrian lineaments control off-axis melt • Magmatic extension in Ethiopian rift is not ocean like • Magmatic belts at basins margins may not be seafloor spreading ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Publication Date: 2015-02-10
    Description: Methods for measuring aerobic methane oxidation (MOx) rates in aquatic environments are often based on the incubation of water samples, during which the consumption of methane (CH4) is monitored. Typically, incubation vessels are sealed with butyl rubber because these elastomers are essentially impermeable for gases. We report on the potential toxicity of five different commercially available, lab-grade butyl stoppers on MOx activity in samples from marine and lacustrine environments. MOx rates in incubations sealed with non-halogenated butyl were 〉 50% lower compared to parallel incubations with halogenated butyl rubber stoppers, suggesting toxic effects associated with the use of the non-halogenated butyl type. Aqueous extracts of non-halogenated butyl rubber were contaminated with high amounts of various organic compounds including potential bactericides such as benzyltoluenes and phenylalkanes. Comparably small amounts of organic contaminants were liberated from the halogenated butyl rubber stoppers but only two halogenated stopper types were found that did not seem to leach any organics into the incubation medium. Furthermore, the non-halogenated and two types of the halogenated butyl elastomers additionally leached comparably high amounts of zinc. While the source of the apparent toxicity with the use of the non-halogenated rubber stoppers remains elusive, our results indicate that leaching of contaminants from some butyl rubber stoppers can severely interfere with the activity of MOx communities, highlighting the importance of testing rubber stoppers for their respective contamination potential. The impact of leachates from butyl rubber on the assessment of biogeochemical reaction rates other than MOx seems likely but needs to be verified.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3The Ocean Floor : Bruce Heezen commemorative volume, (A Wiley-Interscience publication), Chichester, Wiley, pp. 147-163, ISBN: 0-471-10091-9
    Publication Date: 2014-05-12
    Description: The sedimentation regime off Northwest Africa is shaped by: (1) structur~al factors. which result in generallv low relief on land. shelf widths between 40 and more than 120 km. and av-erage sfope inclinations between 10 30' and 30; (2) land climates. which contral the delivery of terrigenous particles to the margin: (3) water movements including boundary currents and upwelling; and (4) the post- Pleistocene sea level rise. This chapter combines published and new results arising from research into the sedimentation processes off Northwest Africa. and emphasizes particularly the activities of the Kiel marine geological group during the past few years. Reviews of cruise activities and results were given in Closs et al. (1969) (Meteor cruise 8. 1967. off Morocco) . Seibold (1972) (Meteor cmise 25 . 1971. off Sahara to Central Senegal). Seibold and Hinz (1976) (Meteor cmise 39,1975 . and Valdivia cruise 10. 1975, from Morocco to South Senegal), and Waiden et al. (1974) (Meteor cmise 30, 1973, off Sierra Leone). Some of these cmises were used for pre- or post-site surveys for the Deep-Sea Drilling Project, or to add undisturbed Quaternary cores to the Glomar Challenger cores (leg 41, ] 975; Lancelot, et al .• 1978); leg 47 A, Arthur er al .• 1979; Lutze et al., 1979). We have concentrated our geological investigations on a number of standard profiles from the shelf to the upper continental rise as given in Figure 1. The manuscript was finished May 1979.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2019-01-30
    Description: The purpose of this list of digital platforms is to facilitate the research of scientific data (articles, books, conferences, websites, indexers, etc.) by students of all undergraduate levels. The interface of platforms have similarities and because of this, low degree of difficulty of use. I emphasize that the key to an excellent literature search on digital platforms is to choose the right "keyword".
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/zip
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2019-03-21
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2019-03-21
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2019-03-21
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2019-03-21
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Geophysical Research Letters, Wiley, 46(8), pp. 4288-4298, ISSN: 0094-8276
    Publication Date: 2021-02-16
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Publication Date: 2019-04-29
    Description: Sedimentary architecture and morphogenetic evolution of a polar bay-mouth gravel-spit system are revealed based on topographic mapping, sedimentological data, radiocarbon dating and ground-penetrating radar investigations. Data document variable rates of spit progradation in reaction to atmospheric warming synchronous to the termination of the last glacial re-advance (LGR, 0.45–0.25 ka BP), the southern hemisphere equivalent of the Little Ice Age cooling period. Results show an interruption of spit progradation that coincides with the proposed onset of accelerated isostatic rebound in reaction to glacier retreat. Spit growth resumed in the late 19th century after the rate of isostatic rebound decreased, and continues until today. The direction of modern spit progradation, however, is rotated northwards compared with the growth axis of the early post-LGR spit. This is interpreted to reflect the shift and strengthening in the regional wind field during the last century. A new concept for the interplay of polar gravel-spit progradation and glacio-isostatic adjustment is presented, allowing for the prediction of future coastal evolution in comparable polar settings.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Geophysical Research Letters, Wiley, 46, ISSN: 0094-8276
    Publication Date: 2019-07-10
    Description: Here we evaluate five atmospheric reanalyses in an Arctic gateway during late summer. The reanalyses include ERA5, ERA-Interim, JRA-55, CFSv2 and MERRA-2. We use observations from 50 radiosondes launched in the Fram Strait around 79-80˚N, between 25 August – 11 September 2017. Crucially, data from 27 radiosondes were not transmitted to the Global Telecommunications System (GTS), and therefore not assimilated into any reanalysis. In most reanalyses, the magnitude of wind speed and humidity errors are similar for profiles with and without data assimilation. In cases without data assimilation, correlation coefficients (R) exceed 0.88 for temperature, wind speed and specific humidity, in all reanalyses. Overall, the newly released ERA5 has higher correlation coefficients than any other reanalyses as well as smaller biases and root mean square errors, for all three variables. The largest improvements identified in ERA5 are in its representation of the wind field, and temperature profiles over warm water.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Publication Date: 2019-08-13
    Description: The importance of macrobenthos in benthic‐pelagic coupling and early diagenesis of organic carbon (OC) has long been recognized but has not been quantified at a regional scale. By using the southern North Sea as an exemplary area we present a modelling attempt to quantify the budget of total organic carbon (TOC) reworked by macrobenthos in seafloor surface sediments. Vertical profiles in sediments collected in the field indicate a significant but nonlinear correlation between TOC and macrobenthic biomass. A mechanistic model is used to resolve the bi‐directional interaction between TOC and macrobenthos. A novelty of this model is that bioturbation is resolved dynamically depending on variations in local food resource and macrobenthic biomass. The model is coupled to 3D hydrodynamic‐biogeochemical simulations to hindcast the mutual dependence between sedimentary TOC and macrobenthos from 1948 to 2015. Agreement with field data reveals a satisfactory model performance. Our simulations show that the preservation of TOC in the North Sea sediments is not only determined by pelagic conditions (hydrodynamic regime and primary production) but also by the vertical distribution of TOC, bioturbation intensity, and the vertical positioning of macrobenthos. Macrobenthos annually ingest 20%–35% and in addition vertically diffuse 11%–22% of the total budget of TOC in the upper‐most 30 cm sediments in the southern North Sea. This result indicates a central role of benthic animals in modulating the OC cycling at the sediment‐water interface of continental margins.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Paleoceanography and Paleoclimatology, Wiley, 34, pp. 432-435
    Publication Date: 2019-06-23
    Description: Age control and paleoceanographic evidence of marine sediment records might be challenged if authors solely build their stratigraphy on visual correlation to apparently well‐dated records from the same ocean basin, using, for example, highly resolved X‐ray fluorescence‐based element‐count records and correlation tools such as AnalySeries. While per se perfectly reasonable, this approach bears the risk of missing stratigraphic gaps in the sedimentary record and thus might result in imprecise and/or flawed interpretations. Here we present a unique series of 14 planktic 14C ages from a 7‐cm section of East Pacific Rise core PS75/059‐2. The ages suggest a 14‐ky‐long period of low‐to‐zero deposition during Last Glacial Maximum, mainly marked by continuous redistribution of winnowed foraminifers, probably the result of enhanced bottom currents, moreover, by some bioturbational mixing. On the basis of this data we demonstrate the impact of the hiatus on a South Pacific transect of apparent benthic ventilation ages (ΔΔ14C values) and their meaning for estimates of CO2 stored in Last Glacial Maximum Pacific deep waters.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2018-12-19
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Journal of Geophysical Research-Oceans, Wiley, 123(12), pp. 8862-8876, ISSN: 0148-0227
    Publication Date: 2019-01-25
    Description: The snow cover on Antarctic sea ice persists during most of the year, contributing significantly to the sea ice mass budget due to comprehensive seasonal transition processes within the snowpack as well as at the snow/ice interface. Consequently, snow on sea ice varies not only in depth but also in particular in its physical characteristics such as snow density and stratigraphy. In order to quantify the heterogeneous nature of the Antarctic snowpack on different spatial scales, that is, small (〈10 m), floe‐size (1‐2 km), and regional (seasonal/perennial ice) scales, we present here a case study of snow analyses in the Weddell Sea in austral winter 2013. The resulting high variability of snow parameters in the basal snow layer reveals the need to distinguish between seasonal and perennial ice regimes, when retrieving, for example, snow depth using satellite microwave radiometry. Considering the full vertical snow column, a more detailed distinction of the perennial sea ice regime into, for example, more ice classes is suggested in order to represent the high variability range. For the internal snowpack variability, however, we identify the grain size variability as the main driver, while snow density variations can be neglected. Moving from regional to floe‐size scales, a similar variability range of the studied snow properties is found, suggesting that a large number of snow samples on a few floes is more crucial than covering a large region with fewer floe‐scale measurements. The spatiotemporally heterogeneous variability in snow accumulation, redistribution, and metamorphism is, however, too large to upscale the given findings beyond regional scale.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Publication Date: 2017-06-12
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Publication Date: 2017-09-13
    Description: This paper investigates new observations from the poorly understood region between the Kara and Laptev Seas in the Eastern Arctic Ocean. We discuss relevant circulation features including riverine freshwater, Atlantic-derived water, and polynya-formed dense water, emphasize Vilkitsky Strait (VS) as an important Kara Sea gateway, and analyze the role of the adjacent 250 km-long submarine Vilkitsky Trough (VT) for the Arctic boundary current. Expeditions in 2013 and 2014 operated closely spaced hydrographic transects and 1 year-long oceanographic mooring near VT’s southern slope, and found persistent annually averaged flow of 0.2 m s21 toward the Nansen Basin. The flow is nearly barotropic from winter through early summer and becomes surface intensified with maximum velocities of 0.35 m s21 from August to October. Thermal wind shear is maximal above the southern flank at 30 m depth, in agreement with basinward flow above VT’s southern slope. The subsurface features a steep front separating warm (–0.58C) Atlantic-derived waters in central VT from cold (〈–1.58C) shelf waters, which episodically migrates across the trough indicated by current reversals and temperature fluctuations. Shelf-transformed waters dominate above VT’s slope, measuring near-freezing temperatures throughout the water column at salinities of 34–35. These dense waters are vigorously advected toward the Eurasian Basin and characterize VT as a conduit for near-freezing waters that could potentially supply the Arctic Ocean’s lower halocline, cool Atlantic water, and ventilate the deeper Arctic Ocean. Our observations from the northwest Laptev Sea highlight a topographically complex region with swift currents, several water masses, narrow fronts, polynyas, and topographically channeled storms.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2017-09-18
    Description: The mechanisms causing widespread flow acceleration of Jakobshavn Isbræ, West Greenland, remain unclear despite an abundance of observations and modeling studies. Here we simulate the glacier's evolution from 1985 to 2016 using a three-dimensional thermomechanical ice flow model. The model captures the timing and 90% of the observed changes by forcing the calving front. Basal drag in the trough is low, and lateral drag balances the ice stream's driving stress. The calving front position is the dominant control on changes of Jakobshavn Isbræ since the ice viscosity in the shear margins instantaneously drops in response to the stress perturbation caused by calving front retreat, which allows for widespread flow acceleration. Gradual shear margin warming contributes 5 to 10% to the total acceleration. Our simulations suggest that the glacier will contribute to eustatic sea level rise at a rate comparable to or higher than at present.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Publication Date: 2017-12-01
    Description: Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic Water (AW) that rapidly melts and undercuts Greenland's marine-terminating glaciers. Here, we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation (MC) approach. A new 150-m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding major improvements over previous datasets, particularly in the marine-terminating sectors of northwest and southeast Greenland. Our map reveals the total sea level potential of the Greenland Ice Sheet is 7.42±0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains recent calving front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future oceanic forcing.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2016-06-30
    Description: The LAPMv2 program (or Large-Area Photo-Mosaicking Tool v2) was specifically developed for seafloor mapping applications. It is capable of handling datasets of thousands of images, and relies on robust feature detection and matching algorithms (SIFT) as well as on navigation data from underwater vehicles (ROV, AUV, etc.) for the production of photomosaics. Final photomosaics are geo-referenced and saved as GeoTiff for direct import into a Geographic Information System (GIS).
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2016-05-27
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/png
    Format: image/gif
    Format: image/gif
    Format: image/gif
    Format: image/gif
    Format: image/gif
    Format: image/gif
    Format: image/gif
    Format: image/gif
    Format: image/gif
    Format: image/gif
    Format: image/png
    Format: image/png
    Format: image/png
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2016-07-02
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2016-12-07
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2016-07-11
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: image/png
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2016-07-12
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2017-02-13
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/plain
    Format: text/csv
    Format: text/csv
    Format: text/plain
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Publication Date: 2017-05-04
    Description: We present a simulation of Antarctic iceberg drift and melting that includes small, medium-sized, and giant tabular icebergs with a realistic size distribution. For the first time, an iceberg model is initialized with a set of nearly 7000 observed iceberg positions and sizes around Antarctica. The study highlights the necessity to account for larger and giant icebergs in order to obtain accurate melt climatologies. We simulate drift and lateral melt using iceberg-draft averaged ocean currents, temperature, and salinity. A new basal melting scheme, originally applied in ice shelf melting studies, uses in situ temperature, salinity, and relative velocities at an iceberg's bottom. Climatology estimates of Antarctic iceberg melting based on simulations of small (≤ 2.2 km), 'small-to-medium'-sized (≤ 10 km), and small-to-giant icebergs (including icebergs 〉 10 km) exhibit differential characteristics: successive inclusion of larger icebergs leads to a reduced seasonality of the iceberg meltwater flux and a shift of the mass input to the area north of 58 °S, while less meltwater is released into the coastal areas. This suggests that estimates of meltwater input solely based on the simulation of small icebergs introduce a systematic meridional bias; they underestimate the northward mass transport and are, thus, closer to the rather crude treatment of iceberg melting as coastal runoff in models without an interactive iceberg model. Future ocean simulations will benefit from the improved meridional distribution of iceberg melt, especially in climate change scenarios where the impact of iceberg melt is likely to increase due to increased calving from the Antarctic ice sheet.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2017-09-25
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    facet.materialart.
    Unknown
    American Geophysical Union
    In:  EPIC3Journal of Geophysical research: Ocean, American Geophysical Union, 122, pp. 1-18
    Publication Date: 2017-11-12
    Description: We collected Arctic Ocean water column samples for methane (CH4) and nitrous oxide (N2O) analysis on three separate cruises in the summer and fall of 2015, covering a ~10,000 km transect from the Bering Sea to Baffin Bay. This provided a three-dimensional view of CH4 and N2O distributions across contrasting hydrographic environments, from the oligotrophic waters of the deep Canada Basin and Baffin Bay, to the productive shelves of the Bering and Chukchi Seas. Percent saturation relative to atmospheric equilibrium ranged from 30-800% for CH4 and 75-145% for N2O, with the highest concentrations of both gases occurring in the northern Chukchi Sea. Nitrogen cycling in the shelf sediments of the Bering and Chukchi Seas likely constituted the major source of N2O to the water column, and the resulting high N2O concentrations were transported across the Arctic Ocean in eastward-flowing water masses. Methane concentrations were more spatially heterogeneous, reflecting a variety of localized inputs, including likely sources from sedimentary methanogenesis and sea ice processes. Unlike N2O, CH4 was rapidly consumed through microbial oxidation in the water column, as shown by the 13C enrichment of CH4 with decreasing concentrations. For both CH4 and N2O, sea-air fluxes were close to neutral, indicating that our sampling region was neither a major source nor sink of these gases. Our results provide insight into the factors controlling the distribution of CH4 and N2O in the North American Arctic Ocean, and an important baseline data set against which future changes can be assessed.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2017-10-16
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Global Biogeochemical Cycles, Wiley, ISSN: 0886-6236
    Publication Date: 2017-10-27
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2017-10-29
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Publication Date: 2019-12-03
    Description: The Southern Hemisphere Antarctic stratosphere experienced two noteworthy events in 2015: a significant injection of sulfur from the Calbuco volcanic eruption in Chile in April, and a record-large Antarctic ozone hole in October and November. Here, we quantify Calbuco's influence on stratospheric ozone depletion in austral spring 2015 using observations and an earth system model. We analyze ozonesondes, as well as data from the Microwave Limb Sounder. We employ the Community Earth System Model, version 1, with the Whole Atmosphere Community Climate Model (CESM1(WACCM)) in a specified dynamics setup, which includes calculations of volcanic effects. The Cloud Aerosol Lidar with Orthogonal Polarization data indicate enhanced volcanic liquid sulfate 532 nm backscatter values as far poleward as 68°S during October and November (in broad agreement with WACCM). Comparison of the location of the enhanced aerosols to ozone data supports the view that aerosols played a major role in increasing the ozone hole size, especially at pressure levels between 150 and 100 hPa. Ozonesonde vertical ozone profiles from the sites of Syowa, South Pole, and Neumayer, display the lowest individual October or November measurements at 150 hPa since the 1991 Mt. Pinatubo eruption period, with Davis showing similarly low values, but no available 1990s data. The analysis suggests that under the cold conditions ideal for ozone depletion, stratospheric volcanic aerosol particles from the moderate-magnitude eruption of Calbuco in 2015 greatly enhanced austral ozone depletion, particularly at 55–68°S, where liquid binary sulfate aerosols have a large influence on ozone concentrations.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Publication Date: 2017-11-06
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Proceedings in Applied Mathematics and Mechanics, Wiley, 16(1), pp. 313-314, ISSN: 16177061
    Publication Date: 2017-11-13
    Description: Ice of Antarctic ice shelves is assumed to behave on long-term as an incompressible viscous fluid, which is dominated on short time scales by the elastic response. Hence, a viscoelastic material model is required. The thermodynamic pressure is treated differently in elastic and viscous models. For small deformations, the elastic isometric stress for ν → 0.5 gives similar results to those solving for pressure in an incompressible laminar flow model. A viscous model, in which the thermodynamic pressure is approximated by an elastic isometric stress, can be easily extended to viscoelasticity.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Publication Date: 2018-01-11
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    Publication Date: 2018-01-09
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2018-01-11
    Description: Near-surface air temperatures close to 0°C were observed in situ over sea ice in the central Arctic during the last three winter seasons. Here we use in situ winter (December–March) temperature observations, such as those from Soviet North Pole drifting stations and ocean buoys, to determine how common Arctic winter warming events are. Observations of winter warming events exist over most of the Arctic Basin. Temperatures exceeding -5°C were observed during 〉30% of winters from 1954 to 2010 by North Pole drifting stations or ocean buoys. Using the ERA-Interim record (1979–2016), we show that the North Pole (NP) region typically experiences 10 warming events (T2m 〉 10°C) per winter, compared with only five in the Pacific Central Arctic (PCA). There is a positive trend in the overall duration of winter warming events for both the NP region (4.25 days/decade) and PCA (1.16 days/decade), due to an increased number of events of longer duration.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2017-12-31
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2018-01-19
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2018-01-19
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2018-03-19
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2018-03-15
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2018-03-26
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2019-01-22
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2018-05-04
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Publication Date: 2018-06-19
    Description: The Beaufort Gyre (BG) is the largest liquid freshwater reservoir of the Arctic Ocean. The liquid freshwater content (FWC) significantly increased in the BG in the 2000s during an anticyclonic wind regime and remained at a high level despite a transition to a more cyclonic state in the early 2010s. It is not well understood to what extent the rapid sea ice decline during this period has modified the trend and variability of the BG liquid FWC in the past decade. Our numerical simulations show that about 50% of the liquid freshwater accumulated in the BG in the 2000s can be explained by the sea ice decline caused by the Arctic atmospheric warming. Among this part of the FWC increase, 60% can be attributed to surface freshening associated with the reduction of the net sea ice thermodynamic growth rate, and 40% to changes in ocean circulation, which makes freshwater more accessible to the BG for storage. Thus, the rapid increase of the BG FWC in the 2000s was due to the concurrence of the anticyclonic wind regime and the high freshwater availability. We also find that if the Arctic sea ice had not declined, the liquid FWC in the BG would have shown a stronger decreasing tendency at the beginning of the 2010s owing to the cyclonic wind regime. From our results we argue that changes in sea ice conditions should be adequately taken into account when it comes to understanding and predicting variations of BG liquid FWC in a changing climate.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2018-07-15
    Description: Understanding the enigmatic intraplate volcanism in the Tristan da Cunha region requires knowledge of the temperature of the lithosphere and asthenosphere beneath it. We measured phasevelocity curves of Rayleigh waves using cross-correlation of teleseismic seismograms from an array of ocean-bottom seismometers around Tristan, constrained a region-average, shear-velocity structure, and inferred the temperature of the lithosphere and asthenosphere beneath the hotspot. The ocean-bottom data set presented some challenges, which required data-processing and measurement approaches different from those tuned for land-based arrays of stations. Having derived a robust, phase-velocity curve for the Tristan area, we inverted it for a shear wave velocity profile using a probabilistic (Markov chain Monte Carlo) approach. The model shows a pronounced low-velocity anomaly from 70 to at least 120 km depth. VS in the low velocity zone is 4.1–4.2 km/s, not as low as reported for Hawaii (�4.0 km/s), which probably indicates a less pronounced thermal anomaly and, possibly, less partial melting. Petrological modeling shows that the seismic and bathymetry data are consistent with a moderately hot mantle (mantle potential temperature of 1,410–1,4308C, an excess of about 50–1208C compared to the global average) and a melt fraction smaller than 1%. Both purely seismic inversions and petrological modeling indicate a lithospheric thickness of 65–70 km, consistent with recent estimates from receiver functions. The presence of warmer-than-average asthenosphere beneath Tristan is consistent with a hot upwelling (plume) from the deep mantle. However, the excess temperature we determine is smaller than that reported for some other major hotspots, in particular Hawaii.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Journal of Geophysical Research-Earth Surface, Wiley, 122, pp. 1619-1634, ISSN: 0148-0227
    Publication Date: 2018-08-30
    Description: Retrogressive thaw slumps (RTSs) are among the most active landforms in the Arctic; their number has increased significantly over the past decades. While processes initiating discrete RTSs are well identified, the major terrain controls on the development of coastal RTSs at a regional scale are not yet defined. Our research reveals the main geomorphic factors that determine the development of RTSs along a 238 km segment of the Yukon Coast, Canada. We (1) show the current extent of RTSs, (2) ascertain the factors controlling their activity and initiation, and (3) explain the spatial differences in the density and areal coverage of RTSs. We mapped and classified 287 RTSs using high-resolution satellite images acquired in 2011. We highlighted the main terrain controls over their development using univariate regression trees model. Coastal geomorphology influenced both the activity and initiation of RTSs: active RTSs and RTSs initiated after 1972 occurred primarily on terrains with slope angles greater than 3.9° and 5.9°, respectively. The density and areal coverage of RTSs were constrained by the volume and thickness of massive ice bodies. Differences in rates of coastal change along the coast did not affect the model. We infer that rates of coastal change averaged over a 39 year period are unable to reflect the complex relationship between RTSs and coastline dynamics. We emphasize the need for large-scale studies of RTSs to evaluate their impact on the ecosystem and to measure their contribution to the global carbon budget.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2019-04-11
    Description: Sea ice formation is accompanied by the rejection of salt which in nature tends to be mixed vertically by the formation of convective plumes. Here we analyze the influence of a salt plume parameterization (SPP) in an atmosphere-sea ice-ocean model. Two 330 years long simulations have been conducted with the AWI Climate Model. In the reference simulation, the rejected salt in the Arctic Ocean is added to the upper-most ocean layer. This approach is commonly used in climate modelling. In another experiment, employing SPP, the rejected salt is vertically redistributed within the mixed layer based on a power law profile that mimics the penetration of salt plumes. We discuss the effects of this redistribution on the simulated mean state and on atmosphere-ocean linkages associated with the intensity of deep water formation. We find that the salt plume parametrization leads to simultaneous increase of sea ice (volume and concentration) and decrease of sea surface salinity in the Arctic. The SPP considerably alters the interplay between the atmosphere and the ocean in the Nordic Seas. The parameterization modifies the ocean ventilation; however, resulting changes in temperature and salinity largely compensate each other in terms of density so that the overturning circulation is not significantly affected.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Journal of Geophysical Research-Earth Surface, Wiley, 123, pp. 779-800, ISSN: 0148-0227
    Publication Date: 2018-12-29
    Description: To better understand the reaction of Arctic coasts to increasing environmental pressure, coastal changes along a 210-km length of the Yukon Territory coast in north-west Canada were investigated. Shoreline positions were acquired from aerial and satellite images between 1951 and 2011. Shoreline change rates were calculated for multiple time periods along the entire coast and at six key sites. Additionally, Differential Global Positioning System (DGPS) measurements of shoreline positions from seven field sites were used to analyze coastal dynamics from 1991 to 2015 at higher spatial resolution. The whole coast has a consistent, spatially averaged mean rate of shoreline change of 0.7 ± 0.2 m/a with a general trend of decreasing erosion from west to east. Additional data from six key sites shows that the mean shoreline change rate decreased from �1.3 ± 0.8 (1950s–1970s) to �0.5 ± 0.6 m/a (1970s–1990s). This was followed by a significant increase in shoreline change to �1.3 ± 0.3 m/a in the 1990s to 2011. This increase is confirmed by DGPS measurements that indicate increased erosion rates at local rates up to �8.9 m/a since 2006. Ground surveys and observations with remote sensing data indicate that the current rate of shoreline retreat along some parts of the Yukon coast is higher than at any time before in the 64-year-long observation record. Enhanced availability of material in turn might favor the buildup of gravel features, which have been growing in extent throughout the last six decades.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2018-09-14
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Publication Date: 2018-09-24
    Description: The Filchner‐Ronne Ice Shelf, the ocean cavity beneath it, and the Weddell Sea that bounds it, form an important part of the global climate system by modulating ice discharge from the Antarctic Ice Sheet and producing cold dense water masses that feed the global thermohaline circulation. A prerequisite for modeling the ice sheet and oceanographic processes within the cavity is an accurate knowledge of the sub‐ice sheet bedrock elevation, but beneath the ice shelf where airborne radar cannot penetrate, bathymetric data are sparse. This paper presents new seismic point measurements of cavity geometry from a particularly poorly sampled region south of Berkner Island that connects the Filchner and Ronne ice shelves. An updated bathymetric grid formed by combining the new data with existing data sets reveals several new features. In particular, a sill running between Berkner Island and the mainland could alter ocean circulation within the cavity and change our understanding of paleo‐ice stream flow in the region. Also revealed are deep troughs near the grounding lines of Foundation and Support Force ice streams, which provide access for seawater with melting potential. Running an ocean tidal model with the new bathymetry reveals large differences in tidal current velocities, both within the new gridded region and further afield, potentially affecting sub‐ice shelf melt rates.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2019-03-21
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    facet.materialart.
    Unknown
    American Geophysical Union
    In:  EPIC3AGU, Fall Meeting 2017, Poster PP51B-1067, New Orleans, 2017-12-15-2017-12-15New Orleans, USA, American Geophysical Union
    Publication Date: 2019-05-12
    Description: Establishing an accurate chronostratigraphy is essential in reconstructing paleoenvironmental changes in the Arctic Ocean. This requisition, however, has been impeded by the lack of biogenic remnants such as calcareous and siliceous microfossils, as well as alteration of paleomagnetic properties by post-depositional processes. Consequently, foundation of chronostratigraphy in the Arctic Ocean has been mostly relying on stratigraphic correlations. This study examines lithological features and physical properties of sediments of gravity core ARA03B-41GC02 collected in the Makarov Basin and correlates with previously studied cores from the western Arctic Ocean, in order to establish an age model that could eventually facilitate a precise reconstruction of paleoenvironmental changes in the western Arctic Ocean. Age control in the uppermost part was determined by AMS 14C dating of planktonic foraminifera and inter-core correlation was conducted in the upper ca. 3.8 m of the core which corresponded to MIS 15. Age constraints older than MIS 15 were treated using cyclostratigraphic model based on Mn-δ18O stack comparison, assuming that brown and high Mn concentration layers represent generally interglacial or interstadial periods. Based on our result, the core bottom corresponds to MIS 28 with an average sedimentation rate of ca. 0.5 cm/ky. The first appearance of detrital carbonate, planktonic foraminifera, and benthic foraminifera occurred during MIS 16, 11, and 7, respectively. MIS 16 is known as the coldest glacial period when δ18O of the LR04 stack first becomes heavier than 5‰; the occurrence of detrital carbonate likely transported from the Canadian Arctic indicates the initial buildup of the large ice sheets in the North America during this time. Since MIS 11 which is known as the warmest interglacial period during the late Pleistocene in the Northern Hemisphere, the appearance of planktonic foraminifera represents the warmer condition during interglacial periods in the western central Arctic Ocean. Additional geochemical and mineralogical proxies need to be conducted for better understanding of depositional environments and sediment provenance as well as transport pathways.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Geophysical Research Letters, Wiley, ISSN: 0094-8276
    Publication Date: 2019-06-16
    Description: Satellite‐derived data suggest an increase in annual primary production following the loss of summer sea ice in the Arctic Ocean. The scarcity of field data to corroborate this enhanced algal production incited a collaborative project combining six annual cycles of sequential sediment trap measurements obtained over a 17‐year period in the Eurasian Arctic Ocean. Here we present microalgal fluxes measured at ~200 m to reflect the bulk of algal carbon production. Ice algae contributed to a large proportion of the microalgal carbon export before complete ice melt and possible detection of their production by satellites. In the northern Laptev Sea, annual microalgal carbon fluxes were lower during the 2007 minimum ice extent than in 2006. In 2012, early snowmelt led to early microalgal carbon flux in the Nansen Basin. Hence, a change in the timing of snowmelt and ice algae release may affect productivity and export over the Arctic basins.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Publication Date: 2020-08-27
    Description: Sea ice dynamics determine the drift and deformation of sea ice. Nonlinear physics, usually expressed in a viscous‐plastic rheology, makes the sea ice momentum equations notoriously difficult to solve. At increasing sea ice model resolution the nonlinearities become stronger as linear kinematic features (leads) appear in the solutions. Even the standard elastic‐viscous‐plastic (EVP) solver for sea ice dynamics, which was introduced for computational efficiency, becomes computationally very expensive, when accurate solutions are required, because the numerical stability requires very short, and hence more, subcycling time steps at high resolution. Simple modifications to the EVP solver have been shown to remove the influence of the number of subcycles on the numerical stability. At low resolution appropriate solutions can be obtained with only partial convergence based on a significantly reduced number of subcycles as long as the numerical procedure is kept stable. This previous result is extended to high resolution where linear kinematic features start to appear. The computational cost can be strongly reduced in Arctic Ocean simulations with a grid spacing of 4.5 km by using modified and adaptive EVP versions because fewer subcycles are required to simulate sea ice fields with the same characteristics as with the standard EVP.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2019-07-15
    Description: Quaternary East Asian winter monsoon (EAWM) evolution has long been attributed to high‐latitude Northern Hemisphere climate change. However, it cannot explain the distinct relationships of the EAWM in the northern and southern East Asian marginal sea in paleoclimatic records. Here we present an EAWM record of the northern East China Sea over the past 300 ka and a transient climate simulation with the Kiel Climate Model through the Holocene. Both proxy record and simulation suggest anticorrelated long‐term EAWM evolution between the northern East China Sea and the South China Sea. We suggest that this spatial discrepancy of EAWM can be interpreted as El Niño–Southern Oscillation (ENSO)‐like controlling, which generates cyclonic/anticyclonic wind anomalies in the northern/southern East Asian marginal sea. This research explains much of the controversy in nonorbital scale variability of Quaternary EAWM records in the East Asian marginal sea and supports a potent role of tropical forcing in East Asian winter climate change.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Publication Date: 2019-08-01
    Description: The Weddell Gyre (WG) is one of the main oceanographic features of the Southern Ocean south of the Antarctic Circumpolar Current which plays an influential role in global ocean circulation as well as gas exchange with the atmosphere. We review the state‐of‐the art knowledge concerning the WG from an interdisciplinary perspective, uncovering critical aspects needed to understand this system's role in shaping the future evolution of oceanic heat and carbon uptake over the next decades. The main limitations in our knowledge are related to the conditions in this extreme and remote environment, where the polar night, very low air temperatures and presence of sea ice year‐round hamper field and remotely sensed measurements. We highlight the importance of winter and under‐ice conditions in the southern WG, the role that new technology will play to overcome present‐day sampling limitations, the importance of the WG connectivity to the low‐latitude oceans and atmosphere, and the expected intensification of the WG circulation as the westerly winds intensify. Greater international cooperation is needed to define key sampling locations that can be visited by any research vessel in the region. Existing transects sampled since the 1980s along the Prime Meridian and along an East‐West section at ~62°S should be maintained with regularity to provide answers to the relevant questions. This approach will provide long‐term data to determine trends and will improve representation of processes for regional, Antarctic‐wide and global modeling efforts – thereby enhancing predictions of the WG in global ocean circulation and climate.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Publication Date: 2020-07-02
    Description: The East Antarctic Ice Sheet (EAIS) is underlain by a series of low‐lying subglacial sedimentary basins. The extent, geology, and basal topography of these sedimentary basins are important boundary conditions governing the dynamics of the overlying ice sheet. This is particularly pertinent for basins close to the grounding line wherein the EAIS is grounded below sea level and therefore potentially vulnerable to rapid retreat. Here we analyze newly acquired airborne geophysical data over the Pensacola‐Pole Basin (PPB), a previously unexplored sector of the EAIS. Using a combination of gravity and magnetic and ice‐penetrating radar data, we present the first detailed subglacial sedimentary basin model for the PPB. Radar data reveal that the PPB is defined by a topographic depression situated ~500 m below sea level. Gravity and magnetic depth‐to‐source modeling indicate that the southern part of the basin is underlain by a sedimentary succession 2–3 km thick. This is interpreted as an equivalent of the Beacon Supergroup and associated Ferrar dolerites that are exposed along the margin of East Antarctica. However, we find that similar rocks appear to be largely absent from the northern part of the basin, close to the present‐day grounding line. In addition, the eastern margin of the basin is characterized by a major geological boundary and a system of overdeepened subglacial troughs. We suggest that these characteristics of the basin may reflect the behavior of past ice sheets and/or exert an influence on the present‐day dynamics of the overlying EAIS.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Journal of Geophysical Research-Atmospheres, Wiley, 123(18), pp. 10162-10184, ISSN: 0148-0227
    Publication Date: 2019-04-11
    Description: Understanding the influence of the Arctic troposphere on the climate at midlatitudes is critical for projecting the impacts of ongoing and anticipated Arctic changes such as Arctic amplification and rapid sea ice decline over the Northern Hemisphere. In this study, we analyze a suite of atmospheric model experiments, with and without atmospheric relaxation toward reanalysis data, to study the impacts of the Arctic troposphere on the midlatitude atmospheric circulation and climate variability. The Arctic troposphere is found to strongly impact the interannual variability of the atmospheric circulation and temperature over the midlatitude continents. The major mechanisms for the impacts of Arctic troposphere include the modulation of the large‐scale atmospheric circulation, the associated heat transport over the continents, and the impacts on synoptic variations in the North Atlantic‐European sector. The impact of the Arctic troposphere on the intensity of the Siberian High is an important factor for how the Arctic can influence temperature variability in south Siberia and East Asia. The trends in the Arctic troposphere in recent decades are closely linked to the recent winter cooling in Northern Eurasia. These recent cooling trends are not driven by the trends in sea surface temperature/sea ice, tropical atmosphere, and the stratosphere. It is argued that the temperature trend pattern of warm Arctic‐cold Eurasia is a manifestation of two possibly independent phenomena and the cooling trend is contributed to by the Arctic troposphere through impacting the large‐scale atmospheric circulation, the atmospheric blocking frequency, and the intensity of the Siberian High.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Geophysical Research Letters, Wiley, ISSN: 0094-8276
    Publication Date: 2019-09-16
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Geophysical Research Letters, Wiley, 46(8), pp. 4413-4420, ISSN: 0094-8276
    Publication Date: 2019-10-07
    Description: The Red Sea is a deep marine basin often considered as small‐scale version of the global ocean. Hydrographic observations and ocean‐atmosphere modeling indicate Red Sea deep water was episodically renewed by wintertime open‐ocean deep convections during 1982–2001, suggesting a renewal time on the order of a decade. However, the long‐term pacing of Red Sea deep water renewals is largely uncertain. We use an annually resolved coral oxygen isotope record of winter surface water conditions to show that the late twentieth century deep water renewals were probably unusual in the context of the preceding ~100 years. More frequent major events are detected during the late Little Ice Age, particularly during the early nineteenth century characterized by large tropical volcanic eruptions. We conclude that Red Sea deep water renewal time is on the order of a decade up to a century, depending on the mean climatic conditions and large‐scale interannual climate forcing.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2020-03-30
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/zip
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2020-03-30
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2020-07-02
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    facet.materialart.
    Unknown
    American Geophysical Union
    In:  EPIC3Earth's Future, American Geophysical Union, 7(12), pp. 1296-1306, ISSN: 2328-4277
    Publication Date: 2021-02-15
    Description: To counteract global warming, a geoengineering approach that aims at intervening in the Arctic ice‐albedo feedback has been proposed. A large number of wind‐driven pumps shall spread seawater on the surface in winter to enhance ice growth, allowing more ice to survive the summer melt. We test this idea with a coupled climate model by modifying the surface exchange processes such that the physical effect of the pumps is simulated. Based on experiments with RCP 8.5 scenario forcing, we find that it is possible to keep the late‐summer sea ice cover at the current extent for the next ∼60 years. The increased ice extent is accompanied by significant Arctic late‐summer cooling by ∼1.3 K on average north of the polar circle (2021–2060). However, this cooling is not conveyed to lower latitudes. Moreover, the Arctic experiences substantial winter warming in regions with active pumps. The global annual‐mean near‐surface air temperature is reduced by only 0.02 K (2021–2060). Our results cast doubt on the potential of sea ice targeted geoengineering to mitigate climate change.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2019-09-12
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    Publication Date: 2020-01-07
    Description: Ocean heat transport through the Barents Sea Opening (BSO) has strong impacts on the Barents Sea ice extent and the climate. In this paper we quantified the contributions from different atmospheric forcing components to the trend and interannual variability of the BSO heat transport. Ocean‐ice model simulations were conducted in which the interannual variation of atmospheric forcing was maintained only in or outside the Arctic in two different simulations. The sum of their BSO heat transport anomalies reasonably replicated the trend and variability from a hindcast simulation. The upward trend of the BSO heat transport mainly stems from the increasing ocean temperature in the subpolar North Atlantic. For the interannual variability, the local wind and upstream forcing are similarly important. The location of the Atlantic Water boundary current in the Nordic Seas, influenced by the cyclonic atmospheric circulation, is crucial in determining part of the BSO inflow variability.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2019-12-28
    Description: Kelps are important providers and constituents of marine ecological niches, the coastal kelp forests. Kelp species have differing distribution ranges, but mainly thrive in temperate and arctic regions. Although the principal factors determining biogeographic distribution ranges are known, genomics could provide additional answers to this question. We sequenced DNA from two Laminaria species with contrasting distribution ranges, Laminaria digitata and Laminaria solidungula. Laminaria digitata is found in the Northern Atlantic with a southern boundary in Brittany (France) or Massachusetts (USA) and a northern boundary in the Arctic, whereas L. solidungula is endemic to the Arctic only. From the raw reads of DNA, we reconstructed both chloroplast genomes and annotated them. A concatenated data set of all available brown algae chloroplast sequences was used for the calculation of a robust phylogeny, and sequence variations were analyzed. The two Laminaria chloroplast genomes are collinear to previously analyzed kelp chloroplast genomes with important exceptions. Rearrangements at the inverted repeat regions led to the pseudogenization of ycf37 in L. solidungula, a gene possibly required under high light conditions. This defunct gene might be one of the reasons why the habitat range of L. solidungula is restricted to lowlight sublittoral sites in the Arctic. The inheritance pattern of single nucleotide polymorphisms suggests incomplete lineage sorting of chloroplast genomes in kelp species. Our analysis of kelp chloroplast genomes shows that not only evolutionary information could be gleaned from sequence data. Concomitantly, those sequences can also tell us something about the ecological conditions which are required for species well‐being.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    facet.materialart.
    Unknown
    Wiley
    In:  EPIC3Biologie in unserer Zeit, Wiley, 49(6), pp. 436-442, ISSN: 0045-205X
    Publication Date: 2019-12-20
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    facet.materialart.
    Unknown
    American Geophysical Union
    In:  EPIC3AGU Fall meeting, San Francisco, CA, 2019-12-09-2019-12-13USA, American Geophysical Union
    Publication Date: 2019-12-17
    Description: During the last decade the Arctic has experienced increasing human development while many native communities continue to live a subsistence lifestyle. Off-road winter tundra travel for resource exploration is most cost effective and least environmentally damaging during winter when the tundra is frozen and snow covered. Climate warming, which is occurring at an amplified rate in the Arctic, likely changes the period when access to the off-road tundra travel is possible. There currently exists, however, large uncertainty as to how climate change will impact the low-cost winter travel access across the tundra. Here we defined safe tundra access when soil temperatures are below a soil type dependent freezing temperature and snow cover is at least 20 cm. Our analysis is based on the simulated soil temperatures and snow depths of Land Surface Models (LSMs) contributing to “The Inter-Sectoral Impact Model Intercomparison Project” (ISIMIP). ISIMIP simulations are based on a common protocol, the same input data, the same spatial (0.5°) and temporal resolution (daily modeling output), and span over the period 1861-2100. The LSMs are forced by four different bias-corrected global circulation models (IPSL-CM5A-LR, GFDL-ESM2M, MIROC5, HadGEM2-ES) and three different future conditions (represented via representative concentration pathways (RCP) 2.6, 6.0, 8.5). The simulation results of our model ensemble (60 model combinations) show consistent permafrost warming and changing snow cover patterns at 60°N. Annual off-road tundra travel is considerably reduced (〉50%) under future climate change scenarios, especially under the RCP8.5. The main reduction can be observed in the spring and autumn (〉30%). The results of the multi-model ensemble differ in magnitude, however, their overall trend is consistent. Our results suggest a high vulnerability and substantial changes to the (subsistence) livelihoods of native communities and increasing costs for off-road resource exploration.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Publication Date: 2021-02-16
    Description: A new global climate model setup using FESOM2.0 for the sea ice‐ocean component and ECHAM6.3 for the atmosphere and land surface has been developed. Replacing FESOM1.4 by FESOM2.0 promises a higher efficiency of the new climate setup compared to its predecessor. The new setup allows for long‐term climate integrations using a locally eddy‐resolving ocean. Here it is evaluated in terms of (1) the mean state and long‐term drift under preindustrial climate conditions, (2) the fidelity in simulating the historical warming, and (3) differences between coarse and eddy‐resolving ocean configurations. The results show that the realism of the new climate setup is overall within the range of existing models. In terms of oceanic temperatures, the historical warming signal is of smaller amplitude than the model drift in case of a relatively short spin‐up. However, it is argued that the strategy of “de‐drifting” climate runs after the short spin‐up, proposed by the HighResMIP protocol, allows one to isolate the warming signal. Moreover, the eddy‐permitting/resolving ocean setup shows notable improvements regarding the simulation of oceanic surface temperatures, in particular in the Southern Ocean.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Publication Date: 2020-01-27
    Description: The Central Asian Pamir Mountains (Pamirs) are a high‐altitude region sensitive to climatic change, with only few paleoclimatic records available. To examine the glacial‐interglacial hydrological changes in the region, we analyzed the geochemical parameters of a 31‐kyr record from Lake Karakul and performed a set of experiments with climate models to interpret the results. δD values of terrestrial biomarkers showed insolation‐driven trends reflecting major shifts of water vapor sources. For aquatic biomarkers, positive δD shifts driven by changes in precipitation seasonality were observed at ca. 31–30, 28–26, and 17–14 kyr BP. Multiproxy paleoecological data and modelling results suggest that increased water availability, induced by decreased summer evaporation, triggered higher lake levels during those episodes, possibly synchronous to northern hemispheric rapid climate events. We conclude that seasonal changes in precipitation‐evaporation balance significantly influenced the hydrological state of a large waterbody such as Lake Karakul, while annual precipitation amount and inflows remained fairly constant.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Publication Date: 2020-02-12
    Description: Four years after the Genomic Observatories Network was formally established as a collaboration between the Group on Earth Observations Biodiversity Observation Network and the Genomic Standards Consortium, we review the development of the network. Considering institutional infrastructure, we note the growing role of omic observation in active and increasingly interlinked marine networks, with examples such as EMBRC/ASSEMBLE, International Long Term Ecological Research Network, AtlantOS, National Association of Marine Labs, Smithsonian MarineGEO, and Partnership on Observation of the Global Oceans. We also note some key human elements essential to meeting the networks' goals, address how the community is evolving, and why performing seemingly simple tasks within a broadly distributed community presents significant challenges even among those who have agreed to use standards. From the perspectives above, we review lessons learned from use cases that leverage Genomic Observatories Network, such as the Autonomous Reef Monitoring Structures (ARMS), Ocean Sampling Day (OSD) and myOSD, which included experiences with citizen science. Looking forward, we survey 1) promising new technologies for in situ biological observation (e.g., cheap 3D printed omics samplers), 2) progress towards adoption of omics methods in marine policy and conservation programs, and 3) opportunities that a Genomic Observatory brings, alone or embedded in a network, to address novel scientific questions and support Essential Biodiversity Variables, Essential Ocean Variables, and indices such as the Ocean Health Index. Given the data intensive nature of omics investigation, we note emerging cyberinfrastructure solutions, such as the Genomic Observatories Metadatabase (GeOMe), an open-access repository for geographic and ecological metadata associated with biosamples, and predictive modeling efforts, such as those of the Island Digital Ecosystem Avatar (IDEA) Consortium. Finally, we explore the potential of Genomic Observatories as components of high-resolution calibration sites. Such observatories would provide super-contextualized "data trusts" for machine learning and artificial intelligence applications that draw on multi-omic observation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Publication Date: 2020-02-12
    Description: Climate change and sustainable use of natural capital demand increased collaboration across the sciences. The first steps for effective collaboration often focus on improving interoperability between observation and analyses methodologies. This is traditionally done through a combination of standards and best practices. The ocean observation community and observing infrastructures - with regionally diverse members working in physics, chemistry, biology and engineering - is looking toward a dynamic consensus-building approach to match the rapid pace of technological evolution. This is an essential part of the long-term cooperation among ocean observing infrastructures. In the last 12 months, the ocean observing community has implemented an Ocean Best Practices System (OBPS). This System was recently adopted by the Intergovernmental Ocean Commission as an international project under GOOS and IODE. The System consists of a permanent OBPS repository hosted by IODE with state-of-the-art semantic discovery and metadata indexing for improved access to best practices and, eventually, to the data associated with them. There have been discussions to understand how to deal with differing best practices and standards on the same observation or analyses objective and other issues that arise from a comprehensive ocean best practices system. A recent survey, to be described, offers options on alternative approaches. Further, we have created a forum, in “Frontiers in Marine Science” for discussion of best practices and their applications. This presentation will cover options for evolving and sustaining ocean best practices across infrastructures. The recommendations build upon the community survey, the OGC experience, the outcomes of the OceanObs’19 conference as well as inputs from the Decade for Ocean Sciences community meetings. The extension of this work to other communities will also be examined.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    facet.materialart.
    Unknown
    American Geophysical Union
    In:  EPIC32018 Ocean Sciences Meeting, Portland, Oregon, USA, 2018-02-11-2018-02-16American Geophysical Union
    Publication Date: 2020-02-12
    Description: Target audience: All ocean scientists who wish to share or discover best practice documents in their domain. Background: A working group convened under the AtlantOS project and including partners from ODIP, IODE, JCOMM, IEEE, and AWI is currently developing new technologies and approaches for handling best practices (BPs) across ocean science. The goal of the working group is to create a sustained repository for BPs, to ease their propagation and adoption. Goals: After briefly describing its work, the BP working group will engage town hall participants in a discussion on 1) how best to find and centrally archive BPs in participants' disciplines and 2) what capacities a central archive of BPs would need to help participants create, discover, share, and archive their BPs. The participant input gathered will be used to further the development of a multidisciplinary repository for BPs and better harmonise ocean observation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Publication Date: 2020-05-14
    Description: IODP Exp. 383 recovered two Pleistocene sedimentary sequences from the upper continental slope along the southernmost Chilean margin that are well positioned to monitor changes in the Antarctic Circumpolar Current (ACC) upstream of the Drake Passage and the history of Patagonian glaciation. These sites are characterized by high sedimentation rates and a complex distribution of siliciclastic sediments with infrequent decimeter-scale beds of calcareous biogenic sediments. Unravelling ocean circulation and climate history from these sites requires a primary understanding of sedimentary provenance and transport mechanisms derived from a complete lithological characterization of the sequence. Here, we integrate downcore shipboard physical properties with sedimentological observations to fully characterize the sequences, evaluate potential for correlation and constrain regional depositional processes. Site U1542 (52°S; 1101 m water depth) consists of a 249 m spliced sedimentary sequence containing Middle Pleistocene to Holocene sediments. It mainly consists of clayey silt that is often interbedded with thin (~75 cm) beds of calcareous sand-bearing clayey to sandy silt with foraminifera and nannofossils or foraminifera-rich nannofossil ooze. Site U1544 (55°S; 2090 m water depth) consists of a 98 m sedimentary sequence obtained from a single hole. Sediments are also dominated by silty clay, but exhibit slightly thicker beds of calcareous ooze and a significantly higher proportion of cm- to dm-scale sand beds that are interpreted as turbidites. Based on the lithology of the recovered sediments and proximity to a glaciated continental margin, terrigenous sediment is likely delivered to these locations by a combination of ice rafting, glacial meltwater plumes, episodic downslope transport from the outer continental shelf and fine-grained sediments transported by the Cape Horn Current entering the Drake Passage as the northern branch of the ACC.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    facet.materialart.
    Unknown
    PANGAEA
    In:  EPIC3Bremerhaven, PANGAEA
    Publication Date: 2017-03-02
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...