1961-2000年西南地区小时降水变化特征

根据西南地区112个站点1961-2000年逐时降水资料,分析了不同季节降水时数、小时雨强、极端强降水时数和极端强降水强度的变化趋势.从降水时数变化来看,夏季西南大部分地区如四川盆地西部、云南、贵州南部等地总降水时数有减少趋势,四川盆地东部和川西高原总降水时数增加;整个区域平均趋势为-0.9%/10a.相应地,极端强降...

Trends of Hourly Precipitation over Southwest China During 1961-2000

Based on the 1961-2000 hourly precipitation data at 112 stations of Southwest China, frequencies and intensities of hourly precipitation and extreme hourly precipitation in four seasons were analyzed. The results show that: 1) in summer, hourly precipitation frequencies decreased in most parts of Southwest China, including the western Sichuan Basin, Yunnan and southern Guizhou, but increased in the eastern Sichuan Basin and the western Sichuan highland; the regional mean hourly precipitation frequencies decreased by 0.9% per 10 years; while extreme hourly precipitation frequencies decreased in the western Sichuan Basin, and increased in most parts of Southwest China, including the eastern Sichuan Basin, western Sichuan highland, most part of Yunnan and Guizhou; the regional mean extreme hourly precipitation frequencies increased by 2.0% per 10 years. In autumn, trends of hourly precipitation frequencies were negative in most of Southwest China; the regional mean hourly precipitation frequencies decreased by 3.5% per 10 years; however trends of extreme hourly precipitation frequencies were not obvious. 2) In summer, trends of average rainfall intensity in most parts of Southwest China, except the western Sichuan Basin, were positive; furthermore, trends of extreme hourly precipitation intensity were also positive in most parts of Southwest China. In autumn, the average rainfall intensity increased in most parts of Yunnan and Guizhou, but decreased in the eastern Sichuan Basin and the western Sichuan highland.