THE CHARACTERISTICS OF SPATIAL DISTRIBUTION AND TYPES OF APRIL-SEPTEMBER RAINFALL IN THE PEARL RIVER BASIN
LIU Yan-qun1, CHEN Chuang-mai2, ZHENG Yong 1 (1. Shaoguan Meteorological Bureau, Shaoguan 512026 China;2. Department of Atmospheric Science, Sun Yat-sen University, Guangzhou 510275 China)
With rainfall data of 51 stations in April-September in the Pearl River basin during 1954-2003, we have applied the Principal Component Analysis method to research the spatial distribution characteristics of April-September rainfall. The results reveal the following. In the Pearl River basin, there is different precipitation varying from 600 mm to 1900 mm in April-September and precipitation decreases gradually from southeast to northwest. The standard deviation distribution decreases gradually from east to west on the whole. The rainfall distribution of the Pearl River basin has five main types:Type I:there is flood (drought) in the whole region, Type II:there is flood (drought) in the north and drought (flood) in the south, Type Ⅲ:there is flood (drought) in the east and drought (flood) in the west, Type IV:there id flood (drought) in the central part and drought (flood) in the east and west, and Type V:there is flood (drought) in center and drought (flood) in north and south. The types of the flood (drought) in the whole region and flood (drought) in the north and drought (flood) in the south appear much more than the others, being 64% of the total. From the 10-year moving average, it is seen that rainfall between April and September in the Pearl River basin region is mainly dry in 1983-1992, and mainly dry in the east and wet in the west in 1967-1971 and wet in the east and dry in the west in 1979.