Abstract

Wind in the free atmosphere is one of the processes recommended by the World Meteorological Organization for climate monitoring. An analysis of the wind regime on large spatial scales presents specific difficulties, since both the vertical and horizontal distributions of wind speed are highly variable. In order to have an idea about the general characteristics of the wind regime in the main atmospheric layers, the Russian Institute of Hydrometeorological Information, World Data Center (RIHMI-WDC), developed a method for monitoring the wind regime of the free atmosphere over the territory of the Russian Federation. The goal of this article is to further develop these works both in relation to the region and in terms of research fields. The article presents the results of monitoring the wind speed in the free atmosphere not only over the territory of Russia, but also over the entire Northern Hemisphere, compares the results of radio sounding data and the ERA5 fifth-generation reanalysis data, and it also considers trends in variability of the wind regime over the period 1985–2018. An analysis of wind characteristics in the troposphere and lower stratosphere of the Northern Hemisphere has been carried out in accordance with the technique developed earlier for monitoring the wind regime of wind speed in the free atmosphere. The analysis was extended to the entire Northern Hemisphere using two data sources: an array of long-term radiosonde measurements performed at Russian Institute of Hydrometeorological Information, World Data Center (RIHMI-WDC) and fifth-generation ERA5 reanalysis. The monitoring results based on the two data sources are qualitatively and quantitatively consistent with each other in the areas covered by the network of aerological stations, except for individual high-mountain regions. The distribution of long-term averages in general terms coincides with the distribution of wind speed based on earlier studies. At the same time, each year is distinguished by its own characteristics, displacements of zones of weak and strong winds, and their intensity. Variability trends over the period 1985–2018 in different regions of the Northern Hemisphere were oppositely directed. The strongest negative wind speed trends reaching –1.5 m s^–1 over 10 years occurred in the lower stratosphere north of 55°–60° N. This may indicate a weakening of the winter west–east transport in this region. In the latitudinal belt 30°–45° N over the Eurasian region, on the contrary, positive trends reaching 1.1 m s^–1 over 10 years have been observed.

中文翻译：

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北半球自由大气中风的气候监测：长期特征和变化趋势

摘要

自由大气中的风是世界气象组织推荐的气候监测过程之一。由于风速的垂直和水平分布变化很大，因此对大空间尺度的风况进行分析存在一定的困难。为了了解主要大气层风况的一般特征，俄罗斯水文气象信息研究所世界数据中心（RIHMI-WDC）开发了一种监测大气层自由大气风况的方法。俄罗斯联邦领土。本文的目标是进一步发展这些与该地区和研究领域相关的工作。文章介绍了俄罗斯境内以及整个北半球自由大气层风速的监测结果，将无线电探空数据与ERA5第五代再分析数据的结果进行了比较，并考虑了1985年至2018年期间风况变化趋势。根据早期开发的自由大气风速风况监测技术，对北半球对流层和平流层下层的风特征进行了分析。该分析使用两个数据源扩展到整个北半球：俄罗斯水文气象信息研究所、世界数据中心 (RIHMI-WDC) 进行的一系列长期无线电探空仪测量和第五代 ERA5 再分析。除个别高山地区外，在高空站网覆盖区域内，两种数据源的监测结果在定性和定量上均一致。一般而言，长期平均值的分布与基于早期研究的风速分布一致。同时，每年都有自己的特点、弱风区和强风区的位移以及强度。1985年至2018年期间北半球不同地区的变化趋势相反。10年来最强的负风速趋势达到–1.5 ms ^–1出现在北纬55°–60°以北的低平流层。这可能表明该地区冬季东西向输送减弱。相反，在欧亚地区北纬 30°–45° 的纬度带，10 年来观察到了达到 1.1 ms ^{–1的积极趋势。}