北方降水性层状云人工增雨潜力区的逐步判别研究

利用1991~1999年9年间飞机人工增雨外场试验期间长春市气象局07:00或19:00(北京时，下同) 的701测风雷达和吉林省气象台713数字化雷达观测资料，依据穿云实际宏观观测资料将增雨潜力区分为:Ⅰ级（较大）和Ⅱ级（较小）。然后应用逐步判别方法求得500 hPa风速的南风分量、回波顶高度、负温层回波厚度/正温层回波厚度、0℃层高度/回波顶高共4个气象因子参加的两组判别函数S1、S2。再用Microsoft VB6.0可视化编程语言，以作业前最近时次探空报中500 hPa风向风速和雷达回波参数为基础将全省划分成9个催化作业区域，根据云系主体回波所在区域，对预催化或正在催化的层状云系进行自动解报、逐步判别方程计算和增雨潜力的自动显示。

Stepwise Discrimination Analysis of Potential Areas for Rain Enhancement in Stratiform Clouds in North China

By means of the data of the 701 windfinding radar at Stations 07:00 and 19:00 of Changchun Meteorological Office and the 713 digital radar from Meteorological Bureau of Jilin Province in the past nine years, the potential areas of rain enhancement are classified into two categories: Class I (larger) and Class II (smaller), according to the data from cross-cloud observation. Two groups of discrimination functions S1, S2, are given, which include four meteorological factors obtained by using stepwise discrimination analysis method: 500 hPa south wind component, height of echo top, (negative temperature layer echo depth)/ (positive temperature layer echo depth) and (height of 0oC layer)/(height of echo top). Then, by using Microsoft VB6.0, Jinlin Province is divided into nine seeding operation areas according to radar echo parameters and 500 hPa wind from the near-time radiosonde observation; the automatic decoding and the rain enhancement potential calculation and automatic display for pre-seeding and stratifrom clouds are conducted.