兰州山谷大气污染的物理机制与防治对策

Atmosphere pollution mechanism along with prevention and cure countermeasure of the Lanzhou hollow basin

分析兰州的一些观测结果得到了这类山谷盆地日间和夜间大气逆温层形成的物理机制．由于山峰加热效应形成日间山谷强的脱地逆温层以及辐射冷却的山谷冷湖效应形成夜间强的逆温层，它们是造成这类特殊条件下的大气污染的根本原因。污染物吸收太阳辐射使上层空气加热，进一步加强了日间的逆温层。环境绿化能减小日间山峰加热效应和夜间辐射冷却造成的冷湖效应，以减弱逆温层减轻污染所以环境绿化是一种增加环境容量，减轻污染的有效措施。

The physical mechanism forming atmospheric inverse temperature layer in daytime and night is got by analyz-ing a number of observation results in hollow basin of Lanzhou City A powerful inverse temperature layer breaking awaybackground in hollow in daytime is formed due to mountain ridge heating effect: and a powerful inverse temperature layerin night is formed due to radiation cooling that forms hollow cold lake effect. They are essential causes of air pollutionunder these especial conditions. The inverse temperature layer is more emphasized due to heating superstratum air as aresult of pollutant absorbing sunshine radiation in daytime. Environment afforestation lets up effect of mountain ridgeheating in daytime and cold lake effect as a result of radiation cooling in night to relief pollution as a result of weakeninginverse temperature layer Therefore the environment afforestation is an effective step of increasing environmental capa-bility and relieving pollution.