Spatio-temporal variability of Antarctic sea-ice thickness and volume obtained from ICESat data using an innovative algorithm

REMOTE SENSING OF ENVIRONMENT

卷:219

Article

Li, Huan^1,2  Xie, Hongjie³  Kern, Stefan⁴  Wan, Wei¹  Ozsoy, Burcu⁵  Ackley, Stephan³  Hong, Yang^1,2,6 

[1] Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China

[2] Tsinghua Univ, State Key Lab Hydrosci & Engn, Dept Hydraul Engn, Beijing 10084, Peoples R China

[3] Univ Texas San Antonio, Dept Geol Sci, Lab Remote Sensing & Geoinformat, San Antonio, TX 78249 USA

[4] Univ Hamburg, Ctr Earth Syst Res & Sustainabil CEN, Integrated Climate Data Ctr, D-20144 Hamburg, Germany

[5] Istanbul Tech Univ, Maritime Fac, Polar Res Ctr PolReC, TR-34940 Istanbul, Turkey

[6] Univ Oklahoma, Sch Civil Engn & Environm Sci, Norman, OK 73019 USA

关键词: Buoyance equation;    Empirical equation;    One-layer method;    Regional variation;    Grid scale;   

DOI  :  10.1016/j.rse.2018.09.031

来源: Elsevier

【 摘 要 】

We use total (sea ice plus snow) freeboard as estimated from Ice, Cloud and land Elevation Satellite (ICESat) Geophysical Laser Altimeter System (GLAS) observations to compute Antarctic sea-ice thickness and volume. In order to overcome assumptions made about the relationship between snow depth and total freeboard or biases in snow depth products from satellite microwave radiometry, we implement a new algorithm. We treat the sea ice-snow system as one layer with reduced density, which we approximate by means of a priori information about the snow depth to sea-ice thickness ratio. We derive this a priori information directly from ICESat total freeboard data using empirical equations relating in-situ measurements of total freeboard to snow depth or sea-ice thickness. We apply our new algorithm (one-layer method or OLM), which uses the buoyancy equation approach without the need for auxiliary snow depth data, to compute sea-ice thickness for every ICESat GLAS footprint from a valid total freeboard. An improved method for sea-ice volume retrieval is also used to derive ice volume at 6.25 km scale. Spatio-temporal variations of sea-ice thickness and volume are then analyzed in the circumpolar Antarctic as well as its six sea sectors: Pacific Ocean, Indian Ocean, Weddell East, Weddell West, Bell-Amund Sea, and Ross Sea, under both interannual and seasonal scales. Because the OLM algorithm relies on only one parameter, the total freeboard, and is independent of auxiliary snow depth information, it is believed to become a viable alternative sea-ice thickness retrieval method for satellite altimetry.

【 授权许可】

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