K指数和低空急流在暴雨过程中的预报特征分析

利用2010年5月～6月初中国南方持续暴雨资料,对K指数、低空急流的预报特征进行了分析。结果发现,K2对未来24 h区域暴雨强度及落区预报具有较好的指示性、超前性和相关性,正相关系数达0.987;低空急流对未来24 h区域暴雨强度及影响范围同样有较好的超前指示意义,相关系数达0.8以上。将K2和低空急流作为主要因子,建立了暴雨落区的基本概念模型。该模型已通过计算机程序,实现了业务自动化。其中,K2为暴雨强度和落区预报提供了重要依据。

Analysis on the Forecast Characteristics of K Index and Low-altitude Jet Stream in the Rainstorm Process

By using the durative rainstorm data in the South China during May-early June in 2010,the forecast characteristics of K index and low-altitude jet stream were analyzed.The results found that K2 had the good indication,advancement and relativity on the intensity and falling zone forecast of regional rainstorm in 24 h in the future,and the positive relative coefficient reached 0.987.The low-altitude jet stream also had the good advancement and indication significance on the intensity and influence scope of regional rainstorm in 24 h in the future,and the relative coefficient reached above 0.8.K2 and the low-altitude jet stream were selected as the main factors,and the basic conceptual model of rainstorm falling zone was established.The conceptual model had passed the computer program and realized the business automation.K2 provided the important basis for the forecast of rainstorm intensity and falling zone.