秦岭山脉对冷空气屏障的理论研究

THEORETICAL STUDY ON COLD-AIR DAMPING OF THE QINLING MOUNTAINS

利用二维大气中尺度数值模式，以１９７７年１月２０日－２２日的冷空气侵袭秦岭山区为例，从观测资料与数值计算两方面分析了由秦岭山脉的屏障作用而引起南北温差的主要原因。结果表明：这种屏障作用不仅体现在秦岭山脉对冷空气的阻挡作用上，而且还与秦岭南坡上的下坡风引起的绝热下沉增温有关。秦岭山脉对冷空气阻挡的动力原因除与秦岭山脉本身的拔海高度较高有关外，还与它的地形形状有关，尤其是位于秦岭北部的渭河河谷，它抑制冷空气入侵谷内，进而阻挡冷空气翻越秦岭山脉。

n this paper. the process of the cold air invading the Qinling Mountains during January 20-22. 1977 is analysed with the observations and is simulated by the mesoscale atmospheric numerical model with a higher-order turbulent clOSure. The simulated results are basically identical with the observed results. Furthermore. by the numerical model, the dynamic anism of the Qinling Mountains screening the cold air from the North is systematically discussed.