On the latitudinal variations of the non-periodic response of minor species induced by a dissipative gravity-wave packet in the MLT region
On the latitudinal variations of the non-periodic response of minor species induced by a dissipative gravity-wave packet in the MLT region
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DOI：
10.1016/j.jastp.2007.01.011
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发表时间：
2007-04
影响因子：
1.9
通讯作者：
Tai-Yin Huang;M. Hickey
中科院分区：
文献类型：
--
作者：
Tai-Yin Huang;M. Hickey
采用光谱全波模式和二维、时间相关的全非线性化学模式，研究了中层/低层热层OH化学中波效应对次要物质的纬度变化。一个耗散重力波包在三个不同的纬度发射，通过北半球的OH夜光发射层向上传播。除了引起小物种密度波动外，由于波的瞬态和耗散导致非加速条件的违反，波包还引起小物种密度的非周期性长期变化。小物种的相关通量是向下的，因此小物种密度通常在高海拔地区减少，在低海拔地区增加。氧原子的向下流动和随后的化学重组特别重要，它本身可以引起其他不太丰富的次要物种的长期大变化。我们的研究表明，波浪引起的非周期性长期变化在高纬度地区最大，在低纬度地区次之，在中纬度地区最小。
A spectral full-wave model and a two dimensional (2-D), time dependent, fully nonlinear chemistry model were used to investigate the latitudinal variations of the wave effects on the minor species in the OH chemistry in the mesosphere/lower thermosphere region. A dissipative gravity-wave packet is launched at three different latitudes propagating upward through the OH nightglow emission layer in the northern hemisphere. In addition to causing the minor species densities to fluctuate, the wave packet also causes non-periodic secular variations of the minor species densities as a consequence of violation of the non-acceleration conditions due to wave transience and dissipation. The associated fluxes of minor species are downward, and consequently minor species densities typically decrease at higher altitudes and increase at lower altitudes. The downward flux and subsequent chemical recombination of atomic oxygen is particularly important and can itself cause large secular variations of other less abundant minor species. Our studies indicate that the wave-induced non-periodic, secular variations are largest at high latitudes, second largest at low latitudes, and smallest at mid-latitudes.