The influence of atmospheric stratification on scatterometer winds

Scatterometers measure surface roughness which is empirically related either to surface stress or to the equivalent neutral stability wind. The importance of atmospheric stability effects for the analysis of these data is studied. For low wind speeds and neutral to slightly stable conditions, neutral stability wind is quite sensitive to stability. A variational analysis procedure for the scatterometer data, which adjusts both the near-surface velocity and temperature, is developed. In simulation tests, temperature analysis increments are found to be small. Also, the differences in the wind analyses due to differences in the temperature background field are small. However, if stability effects are not accounted for, there will be small systematic errors in the wind analysis.