成都大气稳定度频率近年变化及市、郊稳定度差异研究

本文用改进的Pasquill-Turner法统计了成都近8年的大气稳定度频率,分析了其分布和变化特点,研究了变化原因,指出,由于局地环境和气候变化及热岛效应的增强导致稳定度频率的明显逐年改变;并提出用计算级差的方法,处理近郊和远郊的稳定度调级订正问题。结果表明:对不稳定类,近郊比远郊向不稳定方向高一级左右;中性,近郊和远郊无级差;对稳定类,近郊比远郊向稳定方向降约0.3～0.4级。由此推测;当用近郊稳定度推算市心区稳定度时,对不稳定类,市心区相对于近郊至少要向更不稳定方向提级修正一级,中性不修正,考虑热岛效应影响,稳定类可基本不作修正。

STUDY OF YEARLY VARIATION AND THE DIFFERENCE BETWEEN THE URBAN AREA AND THE SUBURBS OF ATMOSPHERIC STABILITY IN CHENGDU

In this paper, the variations of atmospheric stabilities in recent 8 years and their difference in the urban area and the suburbs of Chengdu have been studied by using the improved P - T method and the .way to calculate the grade difference of stability. The results show that the changes of Ideal environment and climate and the effect of heat island lead to the pronounced year - to -year changes of the stability. .For the unstable classes, the stabilities in the urban edge area are one grade higher than that in the subrubs, while fqr the stable classes, the stabilities of the former are 0. 4 grade lower than that of the latter, but for the neutral class the same. According to these results, it was predicted in using the stabilities in the urban edge area to estimate that in the urban central area,for the. unstable classes, the stabilities in the urban central area are at least one grade higher than that in the urban edge area, for the neutral class both are the same, for the stable classes, the difference of the both areas disappears if the effect of heat island is considered.