Three panels showing the difference between experiments that include Aeolus winds assimilation and those that do not.
Difference between experiments that include Aeolus winds assimilation and those that do not (NoAeolus). Here the difference in root-mean-square errors (RMSE) of forecasts and analysis for zonal winds in the tropics (20S – 20N) at 100hPa between the two experiments is shown for May, June and August. The difference is normalized by the RMSE of the Aeolus experiment and the error bars show the 95% confidence intervals. Improvements in the Aeolus experiment appear as negative values. Credit: Žagar et al. [2021], Figure 2
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Geophysical Research Letters

The European Space Agency Earth Explorer mission Aeolus, launched in 2018, is the first with Doppler Wind Lidar onboard and provides measurements of global wind profiles twice a day. Žagar et al. [2021] explore the impact of assimilating Aeolus winds on the European Centre for Medium Range Weather (ECMWF) analyses and forecasts in the tropics.

They compare experiments with and without the assimilation of Aeolus winds. The assimilation of Aelous winds leads to a different representation in the structure of Kelvin Waves. This leads to an improvement of the quality of the forecasts at the tropical tropopause layer. The forecast improvement is particularly strong in the period with a weak easterly Quasi-biennial Oscillation (QBO) in the month of May, likely due to corrections on the characteristics of the Kelvin Waves on these layers.

Citation: Žagar, N., Rennie, M., & Isaksen, L. [2021]. Uncertainties in Kelvin waves in ECMWF analyses and forecasts: Insights from Aeolus observing system experiments. Geophysical Research Letters, 48, e2021GL094716.

―Suzana Camargo, Editor, Geophysical Research Letters

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