Internal gravity waves in the thermosphere during low and high solar activity: Simulation study
Internal gravity waves in the thermosphere during low and high solar activity: Simulation study
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DOI：
10.1029/2009ja015106
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发表时间：
2010-08
影响因子：
--
通讯作者：
Erdal Yiğit;A. Medvedev
中科院分区：
文献类型：
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作者：
Erdal Yiğit;A. Medvedev
GW阻力和波致加热/冷却在太阳活动高时在170公里以下较小，而在170公里以上较大。GW动量沉积的最大值出现在热层上部，但其峰值强度只有前者的一半，在日射量较大的冬季半球为120 vs 240 m s −1 day −1。而不是强大的净冷却在上层热层，GWs产生弱加热在高太阳活动的快速谐波所产生的耗散影响较小。在固定的压力水平下，分子粘度随着太阳活动的增加而增加，但在笛卡尔高度网格中，它可以在较低的热层中增加或减少，这取决于高度。因此，在大多数大气环流模型所处的压力坐标系中，温度升高的影响可被视为大气层耗散增强与垂直膨胀之间的竞争。
GW drag and wave‐induced heating/cooling are shown to be smaller below ∼170 km at high solar activity, and larger above. The maxima of GW momentum deposition occur much higher in the upper thermosphere, but their peaks are half as strong, 120 vs 240 m s −1 day −1 in the winter hemisphere when the insolation is large. Instead of strong net cooling in the upper thermosphere, GWs produce a weak heating at high solar activity created by fast harmonics less affected by dissipation. Molecular viscosity increases with solar activity at fixed pressure levels, but seen in Cartesian altitude grids it can either increase or decrease in the lower thermosphere, depending on the height. Therefore, in pressure coordinates, in which most GCMs operate, the influence of larger temperatures can be viewed as a competition between the enhanced dissipation and vertical expansion of the atmosphere.