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

在NOSTHEM期间，将分析和解释中层/低热层（MLT）中平均风、潮汐参数以及行星波和重力波的纵向差异。这些差异对描述风和波参数纬向平均值的单个站点的代表性的影响将被量化。这将使我们能够定量地估计平均气候学的不确定性，长期趋势，以及在单个站点观测到的年际变化的措施。将确定非纬向结构对平均环流及其变率的贡献。将使用低层和中层大气波和环流参数的半球分析来分析它们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风态之间是否存在显著差异的问题，以及哪些是导致这些差异的基本过程。NOSTHEM项目将利用两个在相似纬度非常相似的VHF流星雷达观测，但在经度上有36°的差异，以便定量地说明非纬向结构对平均环流、波浪和潮汐的影响。 为了获得MLT动力学中非纬向结构的全面图像，将通过使用中层大气环流模式的数值模拟、卫星观测和再分析来完成在Collm和Kazan使用VHF雷达对风和温度的同时观测。NOSTHEM的主要目标是：（1）定量描述两个月MLT环流参数的相似性和差异;（2）根据卫星观测和模拟，将这种分析外推到整个半球视图，（3）对波浪在单个地点环流参数的具体特征中的作用进行定量估计。作为最终目标，我们将通过其潜在过程解释纵向差异，并根据其对半球动态的代表性为单个地点进行的平均气候学和趋势分析的解释提供指导方针。NOSTHEM内的研究将由莱比锡大学气象研究所联合进行，德国莱比锡，以及物理研究所放射物理系，俄罗斯联邦喀山联邦大学。

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.