Development of atmospheric turbulence models on the Complex Terrain and its application to the Atmospheric impact assessment

本研究系统地比较了MY模式和KEASM模式，验证了KEASM模式在大气中应用的可能性。两个模型的参数化过程和Wangara实验的模拟结果表明：（1）MY模型忽略了<μi，μj>和μ<μi，θ>引起的浮力重分布效应和<μ i，θ>引起的剪切重分布效应;因此，MY模型与Businger的观测数据在φ M的不稳定条件下（φ <0）并不一致，与修正MY模型和KEASM相比，MY模型对动量的稳定性函数的评价更高。此外，我们能够验证，动量和热量的涡流系数在很大程度上受湍流长度尺度或湍流能量耗散的影响，而不是封闭模型的假设。因此，MY模型高估了湍流能量耗散，并产生了一个很低的评价PBL高度的模拟Wangara实验。(2)KEASM包括由于地面引起的压力重新分布效应，以及由于<μiμj>和<μiθ>引起的浮力效应和由于<μiθ>引起的剪切效应。KEASM与Businger的观测数据吻合得很好，特别是湍流普朗特数。此外，我们还验证了KEASM将SKEM的常数C_μ修改为通量理查森数的函数，以及将KEASM用于大气应用的可能性。

The present study systematically compared the MY model and KEASM and verified the possibility of using KEASM for atmospheric application. The results of the parameterization process of both models and the simulation of the Wangara experiment are as follows : (1) The MY model neglects the redistribution effects of buoyancy due to <μi, μj> andμ<μi, θ> and of shear due to <μi, θ>. Subsequently, the MY model does not agree with the observed data of Businger in the unstable condition (ζ<0) for φ_M, and largely evaluates the stability function for momentum as compared to the modified MY model and KEASM. In addition, we were able to verify that the eddy coefficients for momentum and heat are to a large degree affected by the turbulent length scale or the turbulent energy dissipation, rather than the closure model assumptions. Consequently, the MY model overestimated the turbulent energy dissipation and yielded a very low evaluation of PBL height for the simulation of the Wangara experiment. (2) KEASM includes the pressure redistribution effects due to the ground, as well as those of buoyancy due to <μiμj> and <μiθ> and of shear due to <μiθ> . KEASM is in good agreement with the data observed by Businger, particularly for turbulent Prandtl number. In addition, we were able to verify that KEASM modifies the constant C_μ of SKEM to be a function of the flux Richardson number as well as the possibility of using KEASM for atmospheric application.