DOI: 10.5194/tc-15-2819-2021
论文题名: Implications of surface flooding on airborne estimates of snow depth on sea ice
作者: Rösel A. ; Farrell S.L. ; Nandan V. ; Richter-Menge J. ; Spreen G. ; Divine D.V. ; Steer A. ; Gallet J.-C. ; Gerland S.
刊名: Cryosphere
ISSN: 19940416
出版年: 2021
卷: 15, 期: 6 起始页码: 2819
结束页码: 2833
语种: 英语
英文摘要: Snow depth observations from airborne snow radars, such as the NASA's Operation IceBridge (OIB) mission, have recently been used in altimeter-derived sea ice thickness estimates, as well as for model parameterization. A number of validation studies comparing airborne and in situ snow depth measurements have been conducted in the western Arctic Ocean, demonstrating the utility of the airborne data. However, there have been no validation studies in the Atlantic sector of the Arctic. Recent observations in this region suggest a significant and predominant shift towards a snow-ice regime caused by deep snow on thin sea ice. During the Norwegian young sea Ice, Climate and Ecosystems (ICE) expedition (N-ICE2015) in the area north of Svalbard, a validation study was conducted on 19 March 2015. This study collected ground truth data during an OIB overflight. Snow and ice thickness measurements were obtained across a two-dimensional (2-D) 400ĝ€¯mĝ€¯×ĝ€¯60ĝ€¯m grid. Additional snow and ice thickness measurements collected in situ from adjacent ice floes helped to place the measurements obtained at the gridded survey field site into a more regional context. Widespread negative freeboards and flooding of the snowpack were observed during the N-ICE2015 expedition due to the general situation of thick snow on relatively thin sea ice. These conditions caused brine wicking into and saturation of the basal snow layers. This causes the airborne radar signal to undergo more diffuse scattering, resulting in the location of the radar main scattering horizon being detected well above the snow-ice interface. This leads to a subsequent underestimation of snow depth; if only radar-based information is used, the average airborne snow depth was 0.16ĝ€¯m thinner than that measured in situ at the 2-D survey field. Regional data within 10ĝ€¯km of the 2-D survey field suggested however a smaller deviation between average airborne and in situ snow depth, a 0.06ĝ€¯m underestimate in snow depth by the airborne radar, which is close to the resolution limit of the OIB snow radar system. Our results also show a broad snow depth distribution, indicating a large spatial variability in snow across the region. Differences between the airborne snow radar and in situ measurements fell within the standard deviation of the in situ data (0.15-0.18ĝ€¯m). Our results suggest that seawater flooding of the snow-ice interface leads to underestimations of snow depth or overestimations of sea ice freeboard measured from radar altimetry, in turn impacting the accuracy of sea ice thickness estimates. © Copyright: Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164794
Appears in Collections: 气候变化与战略
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作者单位: Norwegian Polar Institute, Fram Centre, Tromsø, Norway; Department of Geographical Sciences, University of Maryland, College Park, MD, United States; Centre for Earth Observation Science (CEOS), University of Manitoba, Manitoba, MB, Canada; Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK, United States; Institute of Environmental Physics, University of Bremen, Bremen, Germany; Remote Sensing Technology Institute, German Aerospace Center (DLR), Wessling, Germany
Recommended Citation:
Rösel A.,Farrell S.L.,Nandan V.,et al. Implications of surface flooding on airborne estimates of snow depth on sea ice[J]. Cryosphere,2021-01-01,15(6)