General circulation modeling of the Martian upper atmosphere during global dust storms
General circulation modeling of the Martian upper atmosphere during global dust storms
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DOI：
10.1002/2013je004429
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发表时间：
2013-10
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影响因子：
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通讯作者：
A. Medvedev;Erdal Yiğit;T. Kuroda;P. Hartogh
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文献类型：
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作者：
A. Medvedev;Erdal Yiğit;T. Kuroda;P. Hartogh
用大气环流模式（GCM）进行了模拟，以研究两次大沙尘暴期间的火星高层大气。从地表延伸到约160公里的GCM包括适用于行星热层的次网格尺度重力波的光谱参数化，并规定了对应于春分和夏至（分别为火星年25和28）附近风暴事件的四维尘埃分布。结果表明，100 km以上高层大气的风场和温度场对这类风暴的响应与低层大气一样强烈。在春分风暴期间，除了北方高纬度地区温度上升15 K外，中层顶上方的温度在所有地方都下降了30 K。在冬至风暴，中层顶以上的温度在冬季半球下降了40 K，在夏季半球下降了15 K，在热带地区和130公里以上的夏季半球上升了30-40 K。顺行和逆行的纬向风射流加强整个大气中的所有高度，并在这两个尘埃的情况。这些变化是由分解和未分解波引起的纬向翻转环流改变的结果。沙尘暴期间，中层和低热层大气密度平均增加2 ~ 3倍，这与观测结果一致。
Simulations with a general circulation model (GCM) have been performed to study the Martian upper atmosphere during two major dust storms. The GCM extending from the surface to about 160 km included a spectral parameterization of subgrid‐scale gravity waves suitable for planetary thermospheres, and prescribed four‐dimensional dust distributions corresponding to storm events near the equinox and solstice (Martian years 25 and 28, respectively). The results show that the wind and temperature fields in the upper atmosphere above ∼100 km respond to such storms as intensively as in the lower atmosphere. During the equinoctial storm, the temperature above the mesopause dropped by up to 30 K everywhere except in the Northern Hemisphere high latitudes, where it rose by up to 15 K. At the solstitial storm, the temperature above the mesopause decreased by up to 40 K in the winter hemisphere, by 15 K in the summer hemisphere, and increased by 30–40 K in tropics and in the summer hemisphere above 130 km. Prograde and retrograde zonal wind jets intensified throughout the atmosphere at all heights and during both dust scenarios. These changes are the result of the altered meridional overturning circulation induced by resolved and unresolved waves. Atmospheric density during dust storms enhanced in average by a factor of 2 to 3 in the mesosphere and lower thermosphere, which agrees well with observations.