Basin-scale, high-wavenumber sea surface wind fields from a multiresolution analysis of scatterometer data

Abstract

A numerical technique sensitive to both spectral and spatial aspects of sea surface wind measurements is introduced to transform the irregularly sampled satellite-based scatterometer data into regularly gridded wind fields. To capture the prevailing wavenumber characteristics (power-law dependence) of sea surface wind vector components, wavelet coefficients are computed from the scatterometer measurements along the satellite tracks. The statistics of the wavelet coefficients are then used to simulate high-resolution wind components over the off-track regions where scatterometer data are not available. Using this technique, daily wind fields with controlled spectral features have been produced by combining the low-wavenumber wind fields from ECMWF analyses with the high-wavenumber measurements from the ERS-1 scatterometer. The resulting surface wind fields thus reflect nearly all available measurements affecting surface wind, including the synoptic surface pressure. The new surface wind forces a basin-scale quasigeostrophic ocean model such that the average circulation and energetics are consistent with the previous studies, in which purely synthetic high-wavenumber wind forcing was used.