Non-zonal Structures of Mesosphere/lower Thermosphere Dynamics at Middle Latitudes (NOSTHEM)

在NOSTHEM期间，将分析和解释中间层/低热层(MLT)平均风、潮汐参数、行星波和重力波的经向差异。这些差异对单个站点描述风浪参数纬向平均的代表性的影响将被量化。这将使我们能够定量地估计在单个地点观测到的平均气候学、长期趋势和年际变化测量的不确定性。将确定非纬向结构对平均环流及其变异性的贡献。将使用低层和中层大气波和环流参数的半球分析来分析这些参数在建立纵向差异方面的作用。这将解决西欧和东欧中纬度MLT风场是否存在显著差异的问题，以及导致这些差异的根本过程是什么。NOSTHEM项目将利用两个非常相似的VHF流星雷达观测数据，但在经度上有36°的差异，以定量说明非纬向结构对平均环流、波浪和潮汐的影响。为了全面了解MLT动力学中的非纬向结构，将利用中层大气环流模式、卫星观测和再分析，利用甚高频雷达对COLM和喀山的风和温度进行同时观测。NOSTHEM的主要目标是(1)定量描述两个经度MLT环流参数的异同，(2)根据卫星观测和模拟将这种分析外推到全半球视图，以及(3)定量估计波在单站环流参数特定特征中的作用。作为最终目标，我们将通过潜在的过程来解释经度差异，并根据平均气候学和趋势分析对半球动力学的代表性来解释在单个站点进行的平均气候学和趋势分析。NOSTHEM内的研究将由德国莱比锡气象研究所的莱比锡大学和俄罗斯联邦喀山联邦大学物理研究所的辐射物理系联合进行。

During NOSTHEM, longitudinal differences of mean winds, tidal parameters, and planetary and gravity waves in the mesosphere/lower thermosphere (MLT) will be analyzed and interpreted. The influence of these differences on the representativeness of single sites for describing zonal means of winds and wave parameters will be quantified. This will allow us to quantitatively estimate the uncertainty of mean climatology, long-term trends, and measures of interannual variability observed at single sites. The contribution of non-zonal structures to mean circulation and its variability will be determined. Hemispheric analyses of lower and middle atmosphere waves and circulation parameters will be used to analyze the role of these in establishing longitudinal differences. This will then resolve the question whether there is a significant difference between the mid-latitude MLT wind regimes in Western and Eastern Europe, and which are the underlying processes leading to these differences.The NOSTHEM project will make use of the two very similar VHF meteor radar observations at similar latitude, but with a 36° difference in longitude in order to specify quantitatively the influence of non-zonal structures on mean circulation, waves and tides. In order to obtain a comprehensive picture of non-zonal structures in the MLT dynamics, the concurrent observations of winds and temperatures using VHF radars at Collm and Kazan will be completed by numerical modelling using a circulation model of the middle atmosphere, satellite observations, and reanalyses.Main goals of NOSTHEM are (1) a quantitative description of similarities and differences of MLT circulation parameters at two longitudes, (2) an extrapolation of this analysis to the full hemispheric view based on satellite observations and modelling, and (3) a quantitative estimation of the role of waves in the specific characteristic of circulation parameters at single sites. As a final goal, we shall explain longitudinal differences through their underlying processes, and also provide guidelines for the interpretation of both mean climatology and trend analyses made at single sites in terms of their representativeness for hemispheric dynamics.The research within NOSTHEM will be performed jointly by Universität Leipzig, Institute for Meteorology, Leipzig, Germany, and the Department of Radiophysics, Institute of Physics, Kazan Federal University, Russian Federation.