绿洲沙漠边缘逆湿的数值研究

Numerical Study of Inverse Humidity over the Marginal Zone Between Oasis and Desert

利用包含陆面过程的中尺度数值模式MM5和观测资料,对金塔绿洲边缘逆湿进行了数值研究。模拟结果显示:逆湿出现在沙漠和绿洲交界附近,主要出现在临近绿洲的沙漠上。逆湿和绿洲下游沙漠边缘较充沛的水汽有利于绿洲边缘沙生植物的生长。在临近绿洲的沙漠低层存在大范围的逆湿,随着高度的增加,逆湿范围由绿洲向外围沙漠逐渐减少,强度也在减弱。绿洲风携带的水汽对沙漠的影响有一定距离限制,越靠近绿洲,临近绿洲的沙漠比湿越大,逆湿消失的高度越低。在背景风场较弱的晴好天气下,当存在由绿洲向沙漠辐散的平流以及沙漠上的上升气流和绿洲下沉运动的过渡带位于绿洲边缘时,易形成逆湿。

In this study,a numerical evaluation of the inverse humidity over the marginal zone between Jinta Oasis and the surrounding desert was conducted using the mesoscale numerical model MM5 coupled with LSM and observed data.The Jinta Oasis(39°56′～40°17′N,98°39′～99°08′E),which is 2 152 km2 in area,is located in a typical arid continental drainage basin in the northeastern portion of Jiuquan Prefecture and the central Hexi Corridor,Gansu Province,northwest China.This area is subject to a continental climate and h...