Evaluation of Aeolus Winds by Comparing to AIRS 3D Winds, Rawinsondes, and Reanalysis Grids
A recognized deficiency in the global observing system is an accurate depiction of the 3D structure of the global wind field. The first mission to directly measure wind profiles throughout the troposphere and lower stratosphere is the Aeolus mission, a Doppler wind lidar (DWL) instrument. This is a single horizontal line-of-sight (HLOS) instrument.
An alternate method for deriving 3D winds has been the focus of NASA-sponsored research at the Space Science and Engineering Center (SSEC) using retrievals from the IR hyperspectral instrument, AIRS (Atmospheric Infrared Sounder) on the Aqua satellite. An algorithm was developed to derive 3D winds by tracking moisture features (troposphere) and ozone gradients (stratosphere) from AIRS retrieved vertical profiles of temperature, humidity, and ozone in clear-sky and above clouds.
The Aeolus and AIRS wind products are similar in that they provide a 3D distribution of clear-sky winds in the stratosphere and troposphere. However, there are several inherent differences in the spatial coverage, temporal sampling, and the wind measurement itself from these two methods. Nevertheless, comparisons are very good between co-located AIRS 3D winds and Aeolus Rayleigh clear-sky winds. Moreover, the AIRS and Aeolus Rayleigh HLOS wind speeds compare favorably to HLOS-adjusted rawinsondes and the ERA5 reanalysis wind speeds.
Because of the differences in the active/passive instruments and techniques, there is evidence these two sources of 3D winds may be complementary, with a similar measurement and quality of the wind.
