中国地区对流参数化加热廓线的分析研究和数值试验

为了使MM4模式在我国范围内得到很好的应用，需用我国的气候资料对MM4模式中的对流加热参数进行统计分析，以适应我国各地区气候状态。为此，本文选取了1990～1993年6～8月的常规探空资料，采用郭氏的对流参数化方案，放宽假设后直接计算求得各站点各时次的对流加热率参数，再按气象站的站区分区进行统计。结果表明：黄河以南地区，对流云上、下部的垂直加热率比较均匀，加热廓线峰值偏低，为σ=0.65～0.80，对流云顶也比较高。黄河以北地区，对流云中的垂直加热率分布不均，加热集中在某一层上，加热廓线峰值出现在σ=0.

A Study on the Vertical Profiles of Convective Heating over China and Numerical Experiments

In order to use MM4 model successfully in the whole region of China, it is necessary to improve the cumulus convective heating parameters in MM4 model based on the statistical analysis of real climatic data in China. The routine radiosonde data in June~Aug, 1990~1993 are collected to calculate the vertical profile of convective heating directly at each station for each time level using Kuo’s scheme without unnecessary simplifications. The calculated results are taken statistically in terms of the district of meteorological stations. The results show that the peak values of the profiles at upper and lower parts in convective clouds are all lower (the peak values δ＝0.65~0.80) than the originals in MM4 model, and that the vertical distribution of heating rate on the region south of the Yellow River is rather uniform, but on the region north of the Yellow River the heating is mostly concentrated on some layer (the peak values δ＝0.50~0.65). All these are related to the climate condition and local circulation in each area of China. Substituting these vertical profiles of convective heating for the original heating parameters in MM4 model, it is found that the forecast accuracy on each precipitation level is improved greatly and the false alarm ratio is decreased during the last years of operational application