气候变化领域集成服务门户(CCPortal): An improved CryoSat-2 sea ice freeboard retrieval algorithm through the use of waveform fitting

CCPortal

DOI	10.5194/tc-8-1217-2014
	An improved CryoSat-2 sea ice freeboard retrieval algorithm through the use of waveform fitting
	Kurtz N.T.; Galin N.; Studinger M.
发表日期	2014
ISSN	19940416
卷号	8 期号:4
英文摘要	We develop a physical model capable of simulating the mean echo power of CryoSat-2 SAR- and SARIn-mode waveforms over sea-ice-covered regions. The model simulations are used to show the importance of variations in the radar backscatter coefficient with incidence angle and surface roughness for the retrieval of surface elevation of both sea ice floes and leads. The physical model is used to fit CryoSat-2 waveforms to enable retrieval of surface elevation through the use of lookup tables and a bounded trust region Newton least-squares fitting approach. The use of a model to fit returns from sea ice regions offers advantages over currently used threshold retracking methods, which are here shown to be sensitive to the combined effect of bandwidth-limited range resolution and surface roughness variations. Laxon et al. (2013) have compared ice thickness results from CryoSat-2 and IceBridge, and found good agreement; however consistent assumptions about the snow depth and density of sea ice were not used in the comparisons. To address this issue, we directly compare ice freeboard and thickness retrievals from the waveform-fitting and threshold tracker methods of CryoSat-2 to Operation IceBridge data using a consistent set of parameterizations. The purpose of the comparison is to highlight the physical basis between differences in the retracking methods. For three IceBridge campaign periods from March 2011 to March 2013, mean differences (CryoSat-2 - IceBridge) of 0.144 and 1.351 m are found between the freeboard and thickness retrievals, respectively, using a 50% sea ice floe threshold retracker, while mean differences of 0.019 and 0.182 m are found when using the waveform-fitting method. This suggests the waveform-fitting technique is capable of better reconciling the sea ice thickness data record from laser and radar altimetry data sets through the usage of consistent physical assumptions. © 2014 Author(s).
学科领域	algorithm; CryoSat-2; ice cover; least squares method; numerical model; sea ice; waveform analysis
语种	英语
scopus关键词	algorithm; CryoSat-2; ice cover; least squares method; numerical model; sea ice; waveform analysis
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/120088
作者单位	Cryospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States; Earth System Science Interdisciplinary Center (ESSIC), University of Maryland, College Park, MD, United States; NOAA, Silver Spring, MD, United States
推荐引用方式 GB/T 7714	Kurtz N.T.,Galin N.,Studinger M.. An improved CryoSat-2 sea ice freeboard retrieval algorithm through the use of waveform fitting[J],2014,8(4).
APA	Kurtz N.T.,Galin N.,&Studinger M..(2014).An improved CryoSat-2 sea ice freeboard retrieval algorithm through the use of waveform fitting.Cryosphere,8(4).
MLA	Kurtz N.T.,et al."An improved CryoSat-2 sea ice freeboard retrieval algorithm through the use of waveform fitting".Cryosphere 8.4(2014).