TY - JOUR A1 - Casado, Mathieu A1 - Landais, Amaelle A1 - Picard, Ghislain A1 - Münch, Thomas A1 - Laepple, Thomas A1 - Stenni, Barbara A1 - Dreossi, Giuliano A1 - Ekaykin, Alexey A1 - Arnaud, Laurent A1 - Genthon, Christophe A1 - Touzeau, Alexandra A1 - Masson-Delmotte, Valerie A1 - Jouzel, Jean T1 - Archival processes of the water stable isotope signal in East Antarctic ice cores JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union N2 - The oldest ice core records are obtained from the East Antarctic Plateau. Water isotopes are key proxies to reconstructing past climatic conditions over the ice sheet and at the evaporation source. The accuracy of climate reconstructions depends on knowledge of all processes affecting water vapour, precipitation and snow isotopic compositions. Fractionation processes are well understood and can be integrated in trajectory-based Rayleigh distillation and isotope-enabled climate models. However, a quantitative understanding of processes potentially altering snow isotopic composition after deposition is still missing. In low-accumulation sites, such as those found in East Antarctica, these poorly constrained processes are likely to play a significant role and limit the interpretability of an ice core's isotopic composition. By combining observations of isotopic composition in vapour, precipitation, surface snow and buried snow from Dome C, a deep ice core site on the East Antarctic Plateau, we found indications of a seasonal impact of metamorphism on the surface snow isotopic signal when compared to the initial precipitation. Particularly in summer, exchanges of water molecules between vapour and snow are driven by the diurnal sublimation-condensation cycles. Overall, we observe in between precipitation events modification of the surface snow isotopic composition. Using high-resolution water isotopic composition profiles from snow pits at five Antarctic sites with different accumulation rates, we identified common patterns which cannot be attributed to the seasonal variability of precipitation. These differences in the precipitation, surface snow and buried snow isotopic composition provide evidence of post-deposition processes affecting ice core records in low-accumulation areas. Y1 - 2018 U6 - https://doi.org/10.5194/tc-12-1745-2018 SN - 1994-0416 SN - 1994-0424 VL - 12 IS - 5 SP - 1745 EP - 1766 PB - Copernicus CY - Göttingen ER - TY - GEN A1 - Casado, Mathieu A1 - Landais, Amaelle A1 - Picard, Ghislain A1 - Münch, Thomas A1 - Laepple, Thomas A1 - Stenni, Barbara A1 - Dreossi, Giuliano A1 - Ekaykin, Alexey A1 - Arnaud, Laurent A1 - Genthon, Christophe A1 - Touzeau, Alexandra A1 - Masson-Delmotte, Valerie A1 - Jouzel, Jean T1 - Archival processes of the water stable isotope signal in East Antarctic ice cores T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - The oldest ice core records are obtained from the East Antarctic Plateau. Water isotopes are key proxies to reconstructing past climatic conditions over the ice sheet and at the evaporation source. The accuracy of climate reconstructions depends on knowledge of all processes affecting water vapour, precipitation and snow isotopic compositions. Fractionation processes are well understood and can be integrated in trajectory-based Rayleigh distillation and isotope-enabled climate models. However, a quantitative understanding of processes potentially altering snow isotopic composition after deposition is still missing. In low-accumulation sites, such as those found in East Antarctica, these poorly constrained processes are likely to play a significant role and limit the interpretability of an ice core's isotopic composition. By combining observations of isotopic composition in vapour, precipitation, surface snow and buried snow from Dome C, a deep ice core site on the East Antarctic Plateau, we found indications of a seasonal impact of metamorphism on the surface snow isotopic signal when compared to the initial precipitation. Particularly in summer, exchanges of water molecules between vapour and snow are driven by the diurnal sublimation-condensation cycles. Overall, we observe in between precipitation events modification of the surface snow isotopic composition. Using high-resolution water isotopic composition profiles from snow pits at five Antarctic sites with different accumulation rates, we identified common patterns which cannot be attributed to the seasonal variability of precipitation. These differences in the precipitation, surface snow and buried snow isotopic composition provide evidence of post-deposition processes affecting ice core records in low-accumulation areas. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 716 KW - dronning maud-land KW - shallow firn cores KW - near-surface snow KW - Dome C KW - Kohnen station KW - South Pole KW - climate varibility KW - Vostok station KW - deuterium content KW - GCM analysis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427054 SN - 1866-8372 IS - 716 ER - TY - JOUR A1 - Kokhanovsky, Alexander A1 - Lamare, Maxim A1 - Danne, Olaf A1 - Brockmann, Carsten A1 - Dumont, Marie A1 - Picard, Ghislain A1 - Arnaud, Laurent A1 - Favier, Vincent A1 - Jourdain, Bruno A1 - Le Meur, Emmanuel A1 - Di Mauro, Biagio A1 - Aoki, Teruo A1 - Niwano, Masashi A1 - Rozanov, Vladimir A1 - Korkin, Sergey A1 - Kipfstuhl, Sepp A1 - Freitag, Johannes A1 - Hoerhold, Maria A1 - Zuhr, Alexandra A1 - Vladimirova, Diana A1 - Faber, Anne-Katrine A1 - Steen-Larsen, Hans Christian A1 - Wahl, Sonja A1 - Andersen, Jonas K. A1 - Vandecrux, Baptiste A1 - van As, Dirk A1 - Mankoff, Kenneth D. A1 - Kern, Michael A1 - Zege, Eleonora A1 - Box, Jason E. T1 - Retrieval of Snow Properties from the Sentinel-3 Ocean and Land Colour Instrument JF - Remote sensing N2 - The Sentinel Application Platform (SNAP) architecture facilitates Earth Observation data processing. In this work, we present results from a new Snow Processor for SNAP. We also describe physical principles behind the developed snow property retrieval technique based on the analysis of Ocean and Land Colour Instrument (OLCI) onboard Sentinel-3A/B measurements over clean and polluted snow fields. Using OLCI spectral reflectance measurements in the range 400-1020 nm, we derived important snow properties such as spectral and broadband albedo, snow specific surface area, snow extent and grain size on a spatial grid of 300 m. The algorithm also incorporated cloud screening and atmospheric correction procedures over snow surfaces. We present validation results using ground measurements from Antarctica, the Greenland ice sheet and the French Alps. We find the spectral albedo retrieved with accuracy of better than 3% on average, making our retrievals sufficient for a variety of applications. Broadband albedo is retrieved with the average accuracy of about 5% over snow. Therefore, the uncertainties of satellite retrievals are close to experimental errors of ground measurements. The retrieved surface grain size shows good agreement with ground observations. Snow specific surface area observations are also consistent with our OLCI retrievals. We present snow albedo and grain size mapping over the inland ice sheet of Greenland for areas including dry snow, melted/melting snow and impurity rich bare ice. The algorithm can be applied to OLCI Sentinel-3 measurements providing an opportunity for creation of long-term snow property records essential for climate monitoring and data assimilation studies-especially in the Arctic region, where we face rapid environmental changes including reduction of snow/ice extent and, therefore, planetary albedo. KW - snow characteristics KW - optical remote sensing KW - snow grain size KW - specific surface area KW - albedo KW - Sentinel 3 KW - OLCI Y1 - 2019 U6 - https://doi.org/10.3390/rs11192280 SN - 2072-4292 VL - 11 IS - 19 PB - MDPI CY - Basel ER -