In August 2018, the first Doppler wind lidar in space called Atmospheric Laser Doppler Instrument (ALADIN) was launched on board the satellite Aeolus by the European Space Agency (ESA). Aeolus measures profiles of one horizontal wind component (i.e., mainly the west–east direction) in the troposphere and lower stratosphere on a global basis. Furthermore, profiles of aerosol and cloud properties can be retrieved via the high spectral resolution lidar (HSRL) technique. The Aeolus mission is supposed to improve the quality of weather forecasts and the understanding of atmospheric processes. We used the opportunity to perform a unique validation of the wind products of Aeolus by utilizing the RV Polarstern cruise PS116 from Bremerhaven to Cape Town in November/December 2018. Due to concerted course modifications, six direct intersections with the Aeolus ground track could be achieved in the Atlantic Ocean west of the African continent. For the validation of the Aeolus wind products, we launched additional radiosondes and used the EARLINET/ACTRIS lidar Polly^XT for atmospheric scene analysis. The six analyzed cases prove that Aeolus is able to measure horizontal wind speeds in the nearly west–east direction. Good agreements with the radiosonde observations could be achieved for both Aeolus wind products – the winds observed in clean atmospheric regions called Rayleigh winds and the winds obtained in cloud layers called Mie winds (according to the responsible scattering regime). Systematic and statistical errors of the Rayleigh winds were less than 1.5 and 3.3 m s⁻¹, respectively, when compared to radiosonde values averaged to the vertical resolution of Aeolus. For the Mie winds, a systematic and random error of about 1 m s⁻¹ was obtained from the six comparisons in different climate zones. However, it is also shown that the coarse vertical resolution of 2 km in the upper troposphere, which was set in this early mission phase 2 months after launch, led to an underestimation of the maximum wind speed in the jet stream regions. In summary, promising first results of the first wind lidar space mission are shown and prove the concept of Aeolus for global wind observations.

中文翻译：

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验证大西洋上空的风神风产品

2018年8月，欧洲航天局（ESA）在卫星风神卫星上发射了第一套太空多普勒测风激光雷达，称为大气激光多普勒仪（ALADIN）。风神在全球范围内测量对流层和低平流层中一个水平风分量（即主要是西风向）的剖面。此外，可以通过高光谱分辨率激光雷达（HSRL）技术获取气溶胶和云特性的概况。风神任务应该改善天气预报的质量和对大气过程的理解。我们利用这次机会，通过利用RV Polarstern对风神产品进行了独特的验证从不来梅哈芬（Bremerhaven）于2018年11月/ 12月乘坐PS116号邮轮到开普敦。由于航道的修改，在非洲大陆以西的大西洋上，可以实现与风神地面轨道的六个直接交叉点。为了验证风神产品，我们发射了更多的无线电探空仪，并使用了EARLINET / ACTRIS激光雷达Polly ^XT用于大气场景分析。六个分析案例证明，风神能够测量近西向东的水平风速。风神的风能产品与无线电探空仪的观测结果都可以达成良好的协议-在干净的大气区域中观测到的风称为瑞利风，在云层中获得的风称为三重风（根据负责任的散射制度）。与平均风神垂直分辨率的探空仪值相比，瑞利风的系统误差和统计误差分别小于1.5和3.3 m s ^-1。对于三重风，系统误差约为1 m s ^-1是从不同气候区的六个比较中获得的。然而，还表明，在发射后两个月的早期任务阶段设定的对流层高层2 km的粗略垂直分辨率导致低估了射流区域的最大风速。总而言之，显示了首次风激光雷达太空任务的有希望的初步结果，并证明了风神概念在全球风观测中的应用。