English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. The European Space Agency (ESA) Earth Explorer satellite Aeolus provides continuous profiles of thehorizontal line-of-sight wind component globally from space. It wassuccessfully launched in August 2018 with the goal to improve numericalweather prediction (NWP). Aeolus data have already been successfullyassimilated into several NWP models and have already helped to significantlyimprove the quality of weather forecasts. To achieve this major milestonethe identification and correction of several systematic error sources werenecessary. One of them is related to small fluctuations of the temperaturesacross the 1.5 m diameter primary mirror of the telescope which causevarying wind biases along the orbit of up to 8 m s−1. This paper presents adetailed overview of the influence of the telescope temperature variationson the Aeolus wind products and describes the approach to correct for thissystematic error source in the operational near-real-time (NRT) processing.It was shown that the telescope temperature variations along the orbit aredue to changes in the top-of-atmosphere reflected shortwave and outgoinglongwave radiation of the Earth and the related response of the telescope'sthermal control system. To correct for this effect ECMWF model-equivalentwinds are used as a reference to describe the wind bias in a multiple linearregression model as a function of various temperature sensors located on theprimary telescope mirror. This correction scheme has been in operational useat ECMWF since April 2020 and is capable of reducing a large part of thetelescope-induced wind bias. In cases where the influence of the temperaturevariations is particularly strong it was shown that the bias correction canimprove the orbital bias variation by up to 53 %. Moreover, it wasdemonstrated that the approach of using ECMWF model-equivalent winds isjustified by the fact that the global bias of model u-component winds with respect toradiosondes is smaller than 0.3 m s−1. Furthermore, this paper presents thealternative of using Aeolus ground return winds which serve as a zero-windreference in the multiple linear regression model. The results show that theapproach based on ground return winds only performs 10.8 % worse than theECMWF model-based approach and thus has a good potential for futureapplications for upcoming reprocessing campaigns or even in the NRTprocessing of Aeolus wind products.

Correction of wind bias for the lidar on board Aeolus using telescope temperatures