关键词: 群落多样性, 群落多样性

Abstract: In order to analyze and reveal the extreme precipitation process for nearly 52 years in loess plateau of Gansu Region, the data on the year-by-year daily precipitation of 12 meteorological stations and 4 around in loess plateau of Gansu Region was selected, the thresholds of extreme precipitation were measured by the method of threshold detection as well as climate linear trend analysis, polynomial fitting, inverse distance weighted, Morlet wavelet analysis, Mann-Kendall test and R/S analysis to analyze. The results showed that: (1) extreme precipitation occured mainly in the summer; (2) Four seasons extreme precipitation showed a decrease trend, fall extreme precipitation was decrease most significantly; (3) Summer and autumn extreme precipitation had good correlation with annual extreme precipitation and made the greatest contribution to the annual extreme precipitation; (4) On the spatial distribution, four seasons of extreme precipitation in the north increased significantly, decreased area mainly in the central; (5) It was demonstrated that different vibration periods were displayed very clearly in the extreme precipitation of four seasons in recent 52 years, of about 25 years vibration periods was the most obvious; (6) Only summer extreme precipitation existed abrupt; (6) R/S analysis showed that the future of the extreme precipitation of trends were contrary with the past, the other three seasons were consistent with the past.