山峰加热效应的数值试验研究

已有的资料分析和理论研究表明,山峰加热效应是形成冬季兰州市白天脱地逆温的主要原因。本文利用中尺度数值模式MM5,从数值试验角度研究了兰州市白天温度场和环流场的结构特征。模拟结果表明:冬季,白天日出后的皋兰山峰相对于周围空气是一个热源,在环流场的配合下,皋兰山峰的暖空气向市区上空输送,与河谷温度较低的冷空气形成了白天的脱地逆温;理想"削山"试验的结果表明,山峰海拔越高的山体,加热效应越明显,山谷城市的大气逆温强度和稳定度随着山峰海拔高度的降低而减小。数值试验结果进一步验证和补充了观测和理论分析的结论。

Numerical Simulation of Heating Effect of Mountain Peak

The existed results of analyzing data and theory research have already revealed that heating effect of mountain peak is the main factor of forming inverse temperature of Lanzhou in winter daytime.The meso-scale model MM5 has been used to study the characteristics of temperature and circumfluence structures of Lanzhou daytime.The simulated results show that,in winter daytime,the Gaolan peak is a hot source for ambient atmosphere after sunrise and air temperature above the Gaolan peak is relatively hotter than that of valley city.Therefore the inverse temperature of the valley city has come into been by the cool air above the city and the hot air which transported from the Gaolan Mountain by circumfluence.The simulations verify and make a supplement for observation data and theory analysis.