889 research outputs found
Track of SONNE cruise SO169 with links to navigation files in 1 and 10 sec interval
No full textTrack of SONNE cruise SO169 with links to navigation files in 1 and 10 sec interva
Raw data of physical oceanography during RV POLARSTERN cruise PS134
No full textRaw physical oceanography data was acquired by a ship-based Seabird SBE911plus CTD-Rosette system onboard RV POLARSTERN during research cruise PS134. The CTD was equipped with duplicate sensors for temperature (SBE3plus) and conductivity (SBE4). Additional sensors such as an oxygen sensor (SBE43), a WET Labs C-Star transmissometer, a WET Labs ECO-AFL fluorometer (FLRTD) and an altimeter (Teledyne Benthos PSA-916) were mounted to the CTD. The data was recorded using pre-cruise calibration coefficients. No correction, post-cruise calibration or quality control was applied
Geothermal heat flow beneath Thwaites Glacier in West Antarctica inferred from aeromagnetic data
No full textWe investigated geothermal heat flow derived from new and existing magnetic anomaly data in the Amundsen Sea sector of West Antarctica.
The magnetic anomaly data set (ASE_MagneticCompilation_Dziadeketal.tif) results from a compilation of surveys from RV Polarstern expedition PS104 (2017) and existing, partly unpublished data from various campaigns (TORUS, BBAS, AGASEA and ADMAP2.0). Further details of the processing are given in the manuscript. During PS104 the on board BO-105 helicopter was equipped with a caesium-vapour magnetometer, which was towed with a 30 m long cable and data values are given in Nanotesla.
Curie depth estimates were calculated and served as a boundary condition for geothermal modeling. We split the magnetic anomaly grid into "windows", with 200x200km and a 300x300km dimensions and apply spectral methods to obtain the curie depth. Depths are calculated using GMT fft tool end errors are standard deviation from fft. The results for the respective window sizes are given in 200km_Dziadek_etal_CurieDepth_Results.csv/.nc and 300km_Dziadek_etal_CurieDepth_Results.csv/.nc. .csv corresponds to xyz data and .nc corresponds to the gridded data in NetCDF format, respectively.
The geothermal heat flow models (200km_GHF_windowCenters.csv/.nc and 300km_GHF_windowCenters.csv/.nc) are based on Curie depth estimates in a steady-state model of a homogeneous material with a constant geothermal gradient and thermal conductivity. The km-prefix indicates which magnetic window size was used and values for geothermal heat flow are given at the center of each window in Milliwatts per Squaremeter. Uncertainties of geothermal heat flow (200km_GHF_uncertainty.csv/.nc and 300km_GHF_uncertainty.csv/.nc) are based on Curie depth standard deviation.
This dataset accompanies the manuscript “High geothermal heat flow beneath Thwaites Glacier in West Antarctica inferred from aeromagnetic data", R. Dziadek, F. Ferraccioli & K. Gohl, Communications Earth & Environment, 2021
Workshop - Amundsen Sea Embayment Tectonic and Glacial History - Programme and Abstracts
No full textOverall Objective: Review existing data and identify priorities for future geoscience research (terrestrial, marine and airborne) in the Amundsen Sea embayment (ASE) region required to develop a better understanding of the past, present and future behaviour of this sector of the West Antarctic Ice Sheet (WAIS).
Background: The ASE is the most rapidly changing sector of the WAIS and contains enough ice to raise global sea level by 1.2 m. Over the past few years considerable efforts have been made to acquire new data to improve knowledge of the geological structure, subglacial topography, continental shelf bathymetry and glacial history of this remote region. In this workshop we aim to review the current state of knowledge on the tectonic and glacial evolution of the Amundsen Sea embayment. Particular emphasis will be placed on work that will improve boundary conditions for ice sheet models (e.g. subglacial topography, shelf bathymetry, palaeotopography, heat flow and substrate types) and provide palaeo-data against which model outputs can be compared. There will also be a focus on plans and targets for future scientific drilling that will reveal the history of this sector of the WAIS and its sensitivity to major climate changes
Profile of sediment echo sounding during SONNE cruise SO169 with links to ParaSound data files
No full textAntarctic ice-shelf meltwater outflows in satellite radar imagery: ground-truthing and basal channel observations
No full textIce shelves regulate the flow of the Antarctic ice sheet toward the ocean and its contribution to sea-level rise. Accurately monitoring the basal and surface melting of ice shelves is therefore essential for predicting the ice sheet’s response to climatic warming. In this study, we utilize Sentinel-1A synthetic aperture radar satellite imagery combined with shipboard measurements of water temperature and salinity to investigate the presence of surficial meltwater plumes along the Antarctic coastline. Our approach reveals a strong correlation between areas of pronounced low radar backscatter extending from ice shelves and significant decreases in water temperature and salinity, suggesting meltwater-enriched ocean waters. We propose that the low radar backscatter signature of meltwater outflows is caused by stable stratification of the upper water column, driven by density contrasts from buoyant, low-salinity meltwater and surface current shear that reduce Bragg scattering waves. The resulting smooth water surfaces were observed adjacent to the surface expression of deep basal channels, documented in a helicopter survey along part of the Bellingshausen Sea ice edge. We present high-temporal resolution satellite radar as a tool for identifying meltwater release from beneath ice shelves, capable of all-weather, day-and-night imaging
Master track of POLARSTERN cruise PS134 in 1 sec resolution (zipped, 36.3 MB)
No full textRaw data acquired by position sensors on board RV Polarstern during expedition PS134 was processed to receive a validated master track which can be used as reference of further expedition data. During PS134 two Trimble Marine SPS855 GPS receivers and the iXBlue HYDRINS hydrographic survey inertial navigation system were used as navigation sensors. Data were downloaded from DAVIS SHIP data base (https://dship.awi.de) with a resolution of 1 sec. Processed data are provided as a master track with 1 sec resolution derived from the position sensors' data selected by priority and a generalized track with a reduced set of the most significant positions of the master track
Free-air anomaly data along profile AWI-20160400 during SONNE cruise SO246
No full textGravity data along seismic refraction profile AWI-20160400 was recorded during the cruise SO246 of the German RV SONNE along the central Chatham Rise, west of the Chatham Islands. This dataset contains the calculated free-air gravity anomaly data in 10s interval. See the SO246 cruise report for more information
Agulhas Plateau and Mozambique Ridge: Two LIPs of a kind?
No full textThe seaway south of South Africa represents a critical gateway within the global circulation. Here, warm surface and cold deep and bottom water masses meet and lead to a transfer of heat and salt between the Indian and Atlantic Oceans. This transfer maintains the global thermohaline circulation. The paths of the oceanic currents are strongly influenced by the seafloor topography observed in this region. Thus, the tectonic evolution of the South African continental margin and the gateway starting in Cretaceous times are of major importance in order to understand the evolution of the current system and the transition from the Greenhouse to the Icehouse world. The gateway itself is characterized by the Agulhas Plateau, which has been postulated to originate in the interaction of the Bouvet Hotspot and a triple junction and thus to fall within the world-wide suite of Large Igneous Provinces [Gohl and Uenzelmann-Neben, 2001; Parsiegla, et al., 2008; Uenzelmann-Neben, et al., 1999]. A similar structure has been identified for the crust of the southern Mozambique Ridge [Gohl, et al., 2008]. This rises the question whether those two LIP events were related, their emplacement happened at the same time and how they tie in with other LIP events observed in Late Cretaceous times such as the formation or the Kerguelen LIP. Furthermore, we may speculate on the effect those magmatic events had on the evolution of both oceanic currents and the climate. Similarities as well as differences in crustal structure and evolution and later sedimentary development will be presented for those two structures based on seismic refraction and reflection data. References:Gohl, and G. Uenzelmann-Neben (2001), The crustal role of the Agulhas Plateau, southwest Indian Ocean: Evidence from seismic profiling, Geophysical Journal International, 144, 632-646.Gohl, K., et al. (2008), Is the Mozambique Ridge related to the Agulhas Plateau Large Igneous Province?, Geophysical Research Letters.Parsiegla, N., et al. (2008), The Agulhas Plateau: Structure and evolution of a Large Igneous Province, Geochemistry Journal International, 174, 336-350.Uenzelmann-Neben, G., et al. (1999), Agulhas Plateau, SW Indian Ocean: New evidence for extensive volcanism, Geophysical Research Letters, 26, 1941-1944
Station list and links to master tracks in different resolutions of POLARSTERN cruise ANT-XXVI/3, Wellington - Punta Arenas, 2010-01-30 - 2010-04-05
No full textStation list and links to master tracks in different resolutions of POLARSTERN cruise ANT-XXVI/3, Wellington - Punta Arenas, 2010-01-30 - 2010-04-0
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