Atmospheric coupling by gravity waves:climatology of gravity wave activity, mesopheric turbulence and their relations to solar activity

重力波对于中层大气不同区域之间的耦合是非常重要的。它们通常产生于对流层，被平流层和低层中间层的风场过滤，并至少部分地在中高层和低热层消散。动量和能量的转移产生了一个剩余环流，这是造成MLT区域的温度和风场强烈偏离辐射平衡的原因。在这一建议中，进行调查，研究重力波的活动，他们的过滤的平均环流和沉积的动量和热量。该数据库包括时间序列的中层风测量，部分自1990年以来，和湍流能量耗散率估计的频谱宽度测量与窄波束多普勒中频雷达。在中等太阳活动时（2005-2008年），在CAWSES全球潮汐研究框架内可获得覆盖两个半球高、中、低纬度的广泛数据库。此外，中间层温度的变化是从流星衰变时间的连续雷达观测得出的。详细研究了平流层增暖过程中重力波和行星波的垂直耦合以及波的相互作用。根据对风和温度变化的长期测量，研究了太阳活动对中间层动力和热状态的影响。特别注意的是，中层风场，湍流，中层顶区的温度对太阳活动风暴的响应。将把观测到的重力波活动及其在中层和低热层中的消散情况与大气环流模式所得结果进行比较。

Gravity waves are very important for the coupling between different regions of the middle atmosphere. They are normally created in the troposphere, are filtered by the wind field in the strato- and lower mesosphere and dissipate at least partly in the upper mesosphere and lower thermosphere. The transfer of momentum and energy creates a residual circulation which is responsible for the strong deviations of the temperature and wind field in the MLT region from radiative equilibrium. In this proposal, investigations are done to study the activity of gravity waves, their filtering by the mean circulation and the deposition of momentum and heat. The data base comprises time series of mesospheric wind measurements, partly available since 1990, and turbulent energy dissipation rates estimated from spectral width measurements with a narrow beam Doppler MF radar. At moderate solar activity (2005-2008) an extensive data base covering high, middle, and low latitudes on both hemispheres is available in the frame of the CAWSES Global Tidal Study. Furthermore, the variability of mesospheric temperatures is derived from continuous radar observations of meteor decay times. Vertical coupling by gravity waves and planetary waves as well as wave interaction are investigated in detail during stratospheric warming events. The influence of solar activity on the dynamical and thermal state of the mesosphere is studied on the basis of long-term measurements of wind and temperature variances. Particular attention is devoted to the response of the mesospheric wind field, turbulence, and temperature of the mesopause region on solar activity storms. The observed activity of gravity waves and their dissipation in the mesosphere and lower thermosphere will be compared with the results obtained by general circulation models.