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ICESat observations of Arctic sea ice: A first look
Author(s) -
Kwok Ron,
Zwally H. Jay,
Yi Donghui
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl020309
Subject(s) - freeboard , altimeter , geology , sea ice , sea ice thickness , elevation (ballistics) , arctic ice pack , snow , remote sensing , arctic , climatology , sea level , geodesy , oceanography , geomorphology , geometry , mathematics , fluidized bed , engineering , waste management
Analysis of near‐coincident ICESat and RADARSAT imagery shows that the retrieved elevations from the laser altimeter are sensitive to new openings (containing thin ice or open water) in the sea ice cover as well as to surface relief of old and first‐year ice. The precision of the elevation estimates, measured over relatively flat sea ice, is ∼2 cm. Using the thickness of thin‐ice in recent openings to estimate sea level references, we obtain the sea‐ice freeboard along the altimeter tracks. This step is necessitated by the large uncertainties in the sea surface topography compared to that required for accurate determination of freeboard. Unknown snow depth introduces the largest uncertainty in the conversion of freeboard to ice thickness. Surface roughness is also derived, for the first time, from the variability of successive elevation estimates along the altimeter track. Overall, these ICESat measurements provide an unprecedented view of the Arctic Ocean ice cover at length scales at and above the spatial dimension of the altimeter footprint of ∼70 m.