ALTIMETER ESTIMATION OF SEA-SURFACE WIND STRESS FOR LIGHT TO MODERATEWINDS

Aircraft altimeter and in situ measurements are used to examine relati onships between altimeter backscatter and the magnitude of near-surfac e wind and friction velocities. Comparison of altimeter radar cross se ction with wind speed is made through the modified Chelton-Wentz algor ithm. Improved agreement is found after correcting 10-m winds for both surface current and atmospheric stability. An altimeter friction velo city algorithm is derived based on the wind speed model and an open-oc ean drag coefficient. Close agreement between altimeter- and in situ-d erived friction velocities is found. For this dataset, quality of the altimeter inversion to surface friction velocity is comparable to that for adjusted winds and clearly better than the inversion to true 10-m wind speed.