The prospects for increasing the horizontal resolution of the Aeolus horizontal line‐of‐sight wind profiles

This article evaluates the prospects for increasing the horizontal resolution of the Aeolus horizontal line‐of‐sight (HLOS) wind profiles at the expense of their accuracy. The evaluation is performed by combining a 10‐day atmosphere simulation by the ECMWF model at T3999 horizontal resolution with the CALIPSO observations of atmospheric composition as inputs to the Aeolus simulator. The validation shows that the ECMWF model represents the location and the vertical structure of the observed cloud systems well. At the nominal accumulation length of L ≈ 90 km (from the Aeolus measurement scale of ∼3 km), the Mie‐cloudy retrieval provides 1–4 times fewer observations than Rayleigh‐clear but the Mie‐cloudy HLOS winds have the highest quality with estimated error standard deviation of about 1 m/s in the troposphere and no bias. The experiments with reduced L reveal that neither the observation error standard deviation nor bias of the Mie‐cloudy winds are significantly affected when the accumulation length L varies in the range between 100 and 10 km. At the same time, the number of observations significantly increases as L reduces. This suggests that mesoscale NWP may profit from the Aeolus Mie‐cloudy HLOS profiles with the accumulation lengths as small as 10 km. We study the possibility for increasing the horizontal resolution of the first spaceborne lidar horizontal line‐of‐sight wind profiles measured by the Aeolus platform for their usage in mesoscale models. The evaluation was performed by the nature‐run of the ECMWF model at T3999 horizontal resolution and the CALIPSO observations as an input to the Aeolus simulator. The figure shows a good trade‐off between the true observation error (left‐solid) and the number of observations (right) at small accumulation length for Mie signal.