气候变化领域集成服务门户(CCPortal): Retrieval of snow freeboard of Antarctic sea ice using waveform fitting of CryoSat-2 returns

CCPortal

DOI	10.5194/tc-13-861-2019
	Retrieval of snow freeboard of Antarctic sea ice using waveform fitting of CryoSat-2 returns
	Fons S.W.; Kurtz N.T.
发表日期	2019
ISSN	19940416
EISSN	13
起始页码	861
结束页码	878
卷号	13 期号:3
英文摘要	In this paper we develop a CryoSat-2 algorithm to retrieve the surface elevation of the air-snow interface over Antarctic sea ice. This algorithm utilizes a two-layer physical model that accounts for scattering from a snow layer atop sea ice as well as scattering from below the snow surface. The model produces waveforms that are fit to CryoSat-2 level 1B data through a bounded trust region least-squares fitting process. These fit waveforms are then used to track the air-snow interface and retrieve the surface elevation at each point along the CryoSat-2 ground track, from which the snow freeboard is computed. To validate this algorithm, we compare retrieved surface elevation measurements and snow surface radar return power levels with those from Operation IceBridge, which flew along a contemporaneous CryoSat-2 orbit in October 2011 and November 2012. Average elevation differences (standard deviations) along the flight lines (IceBridge Airborne Topographic Mapper, ATM-CryoSat-2) are found to be 0.016cm (29.24cm) in 2011 and 2.58cm (26.65cm) in 2012. The spatial distribution of monthly average pan-Antarctic snow freeboard found using this method is similar to what was observed from NASA's Ice, Cloud, and land Elevation Satellite (ICESat), where the difference (standard deviation) between October 2011-2017 CryoSat-2 mean snow freeboard and spring 2003-2007 mean freeboard from ICESat is 1.92cm (9.23cm). While our results suggest that this physical model and waveform fitting method can be used to retrieve snow freeboard from CryoSat-2, allowing for the potential to join laser and radar altimetry data records in the Antarctic, larger (1/430cm) regional differences from ICESat and along-track differences from ATM do exist, suggesting the need for future improvements to the method. Snow-ice interface elevation retrieval is also explored as a potential to obtain snow depth measurements. However, it is found that this retrieval method often tracks a strong scattering layer within the snow layer instead of the actual snow-ice interface, leading to an overestimation of ice freeboard and an underestimation of snow depth in much of the Southern Ocean but with promising results in areas such as the East Antarctic sector. © 2019 Author(s).
学科领域	air-snow interaction; airborne thematic mapper; algorithm; continental freeboard; CryoSat; elevation; ICESat; interface; radar; scattering; sea ice; snow; spatial distribution; waveform analysis; Antarctica; Southern Ocean
语种	英语
scopus关键词	air-snow interaction; airborne thematic mapper; algorithm; continental freeboard; CryoSat; elevation; ICESat; interface; radar; scattering; sea ice; snow; spatial distribution; waveform analysis; Antarctica; Southern Ocean
来源期刊	The Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/118911
作者单位	Department of Atmospheric and Oceanic Sciences, University of Maryland, College Park, MD, United States; Earth System Science Interdisciplinary Center (ESSIC), University of Maryland, College Park, MD, United States; Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
推荐引用方式 GB/T 7714	Fons S.W.,Kurtz N.T.. Retrieval of snow freeboard of Antarctic sea ice using waveform fitting of CryoSat-2 returns[J],2019,13(3).
APA	Fons S.W.,&Kurtz N.T..(2019).Retrieval of snow freeboard of Antarctic sea ice using waveform fitting of CryoSat-2 returns.The Cryosphere,13(3).
MLA	Fons S.W.,et al."Retrieval of snow freeboard of Antarctic sea ice using waveform fitting of CryoSat-2 returns".The Cryosphere 13.3(2019).