Global Pressure Fields from Scatterometer Winds

Abstract

A method is presented for computing global surface pressure fields from satellite scatterometer winds. Pressure gradients are estimated using a two-layer similarity planetary boundary layer model in the midlatitudes and a mixed-layer model in the Tropics. A global pressure field is then fit to the pressure gradients by least squares optimization. A series of surface pressure fields calculated from SeaWinds-on-QuikSCAT (Quick Scatterometer) measurements are compared with numerical weather analyses and buoy measurements. Surface pressure observations in the tropical oceans are scarce and come largely from ships of opportunity. At present no buoy in the Atlantic Ocean and only 10 buoys in the Pacific Ocean have pressure sensors. The method presented here suggests that 0.5°-resolution maps of sea surface pressure can be readily retrieved from available satellite remote sensing data every 12 h in near?real time. It is shown that these fields are at least of comparable quality to the ECMWF analyses.