Satellite Estimation of Air-Sea Gas Transfer Velocity During GasEx-3 Using QuikSCAT and Jason-1 Microwave Radar Backscatter
David
M.
Glover, Woods Hole Oceanographic Institution, dglover@whoi.edu
(Presenting)
Nelson
M.
Frew, Woods Hole Oceanographic Institution, nfrew@whoi.edu
Michael
J.
Caruso, University of Miami, RSMAS, mcaruso@rsmas.miami.edu
The Southern Ocean Gas-Exchange Experiment is a new source of field-determined gas transfer velocity (k) data from an energetic wind-wave region of the world ocean. In preparation for this data, we have continued to develop our scatterometer-based algorithm for estimating air-sea gas transfer velocity (k) from QuikSCAT normalized radar backscatter (&sigmao) at 25 km and one day resolution. Our algorithm calculates k from a field-determined, quadratic function of the small-scale wave mean square slope
(< s2>). The < s2>, in turn, is calculated from an empirical function of QuikSCAT normalized radar backscatter (&sigmao). Our algorithm is calibrated with an altimeter-based < s2> - &sigmao relationship using co-located QuikSCAT - altimeter &sigmao. Here we present a regional analysis of the spatial and temporal variability of k in the proposed study area (40-60oS, 30-50oW) during the S.O. GasEx occupation using our most recent algorithm. We further set this variability in context of the contemporaneous global transfer velocity and make comparisons to traditional wind speed - gas transfer velocity parameterizations. This completely new use of SeaWinds/QuikSCAT data allows an important biogeochemical property to be developed from space-based assets beyond traditional ocean color measurements.
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