夏季西北干旱气候形成的数值模拟——高原地形和环流场等的影响

Numerical Simulation of Northwest China Arid Climate Formation — Effects of the Qinghai-Xizang Plateau Terrain and Circulation Field

为了进一步检验和修改本文部分作者先前初步提出的影响夏季西北干旱气候形成的因子及如何相互作用形成西北干旱气候的物理图像，本文继续用一全球大气环流谱模式，设计了５组试验，利用ＥＣＭＷＦ的格点分析值资料，进行了数值模拟。结果表明，青藏高原隆升和环流差异是形成西北干旱气候的重要因子，已提出的西北干旱气候形成的物理图像大体是正确的。

To further test the influences of both the Qinghai-Xizang Plateau (hereafter QXP) raise and the circulation field on Northwest China arid climate and modify the conceptual model of how they interact and cause the Northwest China arid climate, five sets of numerical simulation experiments have been run, utilizing a global spectral model (COLA R15L9) and the ECMWF's gridded analyzed data The main results show: (1) The QXP raise and the circulation changes, especially the former, have important influences on the Northwest China arid climate in summer (2) The mechanism of the QXP raise and the initial circulation affecting the Northwest China dry climate is that both the factors firstly influence the circulation and vertical motion fields over the QXP and its north side and then influence the precipitation over Northwest China arid climate area in middle summer (3) The QXP raise not only intensifies the arid climate of Northwest China and Middle Asia, but also increases considerably the precipitation on east side of the QXP and over North China as well as the South Asia monsoon region