Improvements to estimating the air-sea gas transfer velocity by using dual-frequency, altimeter backscatter

Type Article
Date 2013-12
Language English
Author(s) Goddijn-Murphy Lonneke1, Woolf David2, Chapron Bertrand3, Queffeulou Pierre3
Affiliation(s) 1 : UHI NHC, Environm Res Inst, Thurso KW14 7EE, Scotland.
2 : Heriot Watt Univ, Int Ctr Isl Technol, Stromness, Scotland.
3 : IFREMER, Plouzane, France.
Source Remote Sensing Of Environment (0034-4257) (Elsevier Science Inc), 2013-12 , Vol. 139 , P. 1-5
DOI 10.1016/j.rse.2013.07.026
WOS© Times Cited 7
Keyword(s) Air-sea gas transfer, Satellite altimetry, DMS
Abstract Air-sea gas exchange is affected by sea surface roughness and a previous study shows a significant relation between Ku-band backscattering from satellite altimeters and field estimates of gas transfer velocity, K. Recently C-band backscatter data were made available for altimeters on board the JASON-1 and JASON-2 satellites. In this paper we used experimental data from the same cruises to show that using the difference between the Ku-band and C-band signals to estimate sea surface roughness, and thus reducing the contribution from longer waves, improved the K estimates. This is consistent with the theory that gas transfer is largely controlled by short capillary-gravity waves. For satellite data closer than 2 hr and 0.5 degrees from the K sample stations, the dual-frequency parameterization is found to perform better than a wind speed parameterization that uses in situ wind speed. The improvement supports the hypothesis that gas transfer is more directly related to surface roughness than to surface wind.
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