Surface Wind Variability on Spatial Scales from 1 to 1000 km Observed during TOGA COARE

Abstract

Near-surface wind spectra are considered from three very different data sources, covering a range of spatial scales from 100 to 103 km. The data were observed during the Tropical Ocean Global Atmosphere Coupled Ocean?Atmosphere Response Experiment intensive observation period spanning November 1992 to February 1993. Spectra are examined from low-resolution yet spatially and temporally complete National Centers for Environmental Prediction reanalysis wind fields, moderate resolution satellite-based ERS-1 scatterometer winds, and high-resolution aircraft observations from the National Center for Atmospheric Research Electra. Combined spectra (kinetic energy vs wavenumber k) from these data demonstrate a power?law relation over the entire range in spatial scales, with a best-fit slope very near k?5/3. Energy spectra for subsets of the data support spectral slopes of k?5/3 and k?2, but there is little evidence for a slope of k?3.