Dynamical and radiative forcing of the summer mesopause circulation and thermal structure: 2. Seasonal variations
Dynamical and radiative forcing of the summer mesopause circulation and thermal structure: 2. Seasonal variations
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夏季中层顶环流和热结构的动力和辐射强迫：2. 季节变化
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
G. Thomas
中科院分区：
文献类型：
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作者：
Zhangai Luo;D. Fritts;R. Portmann;G. Thomas
我们在本文中提出了一个扩展的稳定的动力/辐射夏季中层顶模型的弗里茨和罗[这个问题]检查的波动强迫的变化所需的帐户所观察到的季节性变化的温度。该模型采用重力波能量和动量通量和发散提供的动力强迫，包括波动和湍流效应，以及描述O2和O3的太阳加热，O3和CO2的局部热力学平衡（LTE）和非LTE冷却以及由于Oχ和HOχ化学参数化为牛顿冷却的化学加热的辐射强迫。在稳定条件下，对动力和辐射强迫的强烈敏感性提供了诊断动力强迫的时间变异性的能力，这是解释观测到的偏离辐射和化学平衡所必需的。发生最低中层顶温度有点夏至后意味着一个类似的滞后，在最大波强迫，并与现有的动量通量测量和推断的纬向平均风的季节性变化的基础上是一致的。特别是，在中层顶温度在8月期间的快速增加意味着一个快速停止的波强迫伴随着强烈的向东加速的平均流在此期间。
We present in this paper an extension of the steady dynamical/radiative summer mesopause model by Fritts and Luo [this issue] to examine the variability of wave forcing required to account for the observed seasonal changes of temperature. The model employs dynamical forcing provided by gravity wave energy and momentum fluxes and divergence, including wave and turbulence effects, and radiative forcing describing solar heating of O2 and O3, local thermodynamic equilibrium (LTE) and non-LTE cooling of O3 and CO2 and chemical heating due to Oχ and HOχ chemistry parameterized as Newtonian cooling. Strong sensitivity to dynamical and radiative forcing under steady conditions provides an ability to diagnose the temporal variability of dynamical forcing required to account for the observed departures from radiative and chemical equilibrium. The occurrence of minimum mesopause temperatures somewhat after summer solstice implies a similar lag in the maximum wave forcing and is consistent with the available momentum flux measurements and inferences based on the seasonal variations of the zonal mean winds. In particular, the rapid increase in mesopause temperature during August implies a rapid cessation of wave forcing accompanying the strong eastward acceleration of the mean flow during this interval.