气候变化领域集成服务门户(CCPortal): Simulated Ka-and Ku-band radar altimeter height and freeboard estimation on snow-covered Arctic sea ice

CCPortal

DOI	10.5194/tc-15-1811-2021
	Simulated Ka-and Ku-band radar altimeter height and freeboard estimation on snow-covered Arctic sea ice
	Tonboe R.T.; Nandan V.; Yackel J.; Kern S.; Toudal Pedersen L.; Stroeve J.
发表日期	2021
ISSN	19940416
起始页码	1811
结束页码	1822
卷号	15 期号:4
英文摘要	Owing to differing and complex snow geophysical properties, radar waves of different wavelengths undergo variable penetration through snow-covered sea ice. However, the mechanisms influencing radar altimeter backscatter from snow-covered sea ice, especially at Ka-and Ku-band frequencies, and the impact on the Ka-and Ku-band radar scattering horizon or the "track point"(i.e. the scattering layer depth detected by the radar re-tracker) are not well understood. In this study, we evaluate the Ka-and Ku-band radar scattering horizon with respect to radar penetration and ice floe buoyancy using a first-order scattering model and the Archimedes principle. The scattering model is forced with snow depth data from the European Space Agency (ESA) climate change initiative (CCI) round-robin data package, in which NASA's Operation IceBridge (OIB) data and climatology are included, and detailed snow geophysical property profiles from the Canadian Arctic. Our simulations demonstrate that the Ka-and Ku-band track point difference is a function of snow depth; however, the simulated track point difference is much smaller than what is reported in the literature from the Ku-band CryoSat-2 and Ka-band SARAL/AltiKa satellite radar altimeter observations. We argue that this discrepancy in the Ka-and Ku-band track point differences is sensitive to ice type and snow depth and its associated geophysical properties. Snow salinity is first increasing the Ka-and Ku-band track point difference when the snow is thin and then decreasing the difference when the snow is thick (> 0:1 m). A relationship between the Ku-band radar scattering horizon and snow depth is found. This relationship has implications for (1) the use of snow climatology in the conversion of radar freeboard into sea ice thickness and (2) the impact of variability in measured snow depth on the derived ice thickness. For both (1) and (2), the impact of using a snow climatology versus the actual snow depth is relatively small on the radar freeboard, only raising the radar freeboard by 0.03 times the climatological snow depth plus 0.03 times the real snow depth. The radar freeboard is a function of both radar scattering and floe buoyancy. This study serves to enhance our understanding of microwave interactions towards improved accuracy of snow depth and sea ice thickness retrievals via the combination of the currently operational and ESA's forthcoming Ka-and Ku-band dualfrequency CRISTAL radar altimeter missions. © Author(s) 2021.
英文关键词	estimation method; height determination; radar altimetry; sea ice; simulation; snow cover; Arctic Ocean
语种	英语
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202435
作者单位	Danish Meteorological Institute, Copenhagen, Denmark; Center for Earth Observation Sciences (CEOS), Clayton H. Riddell Faculty of Environment, Earth, and Resources, University of Manitoba, Winnipeg, Canada; Cryosphere Climate Research Group, Department of Geography, University of Calgary, Calgary, Canada; Integrated Climate Data Center (ICDC), Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany; National Space Institute, Technical University of Denmark, Lyngby, Denmark; Earth Sciences, University College London, London, United Kingdom
推荐引用方式 GB/T 7714	Tonboe R.T.,Nandan V.,Yackel J.,et al. Simulated Ka-and Ku-band radar altimeter height and freeboard estimation on snow-covered Arctic sea ice[J],2021,15(4).
APA	Tonboe R.T.,Nandan V.,Yackel J.,Kern S.,Toudal Pedersen L.,&Stroeve J..(2021).Simulated Ka-and Ku-band radar altimeter height and freeboard estimation on snow-covered Arctic sea ice.Cryosphere,15(4).
MLA	Tonboe R.T.,et al."Simulated Ka-and Ku-band radar altimeter height and freeboard estimation on snow-covered Arctic sea ice".Cryosphere 15.4(2021).