Abstract:
Abstract：Based on the daily precipitation and evaporation data of 40 meteorological stations in Yunnan Province, the spatial and temporal distribution characteristics of flood and drought were studied by using the RDI index. The results showed that: The annual and seasonal scale droughts and floods is consistent with the historical record in Yunnan Province,The annual RDI index showed a downward trend and a tendency to drought, but not significant; The intensity and stations proportion of floods significantly than droughts before 2001 years;since 2002 the intensity and stations proportion of drought than flood significantly. On the seasonal scale, the spring has a significant wetting trend, the summer, autumn and winter has not significant drying trend; droughts and floods of the spring mutated in 1980, droughts and floods of the summer mutated in 1965. From the spatial distribution, annual, summer, autumn and winter was drought trend in the South and Northeast of Yunnan Province; there has a wet trend in Northwest of Yunnan Province; the rest of the region showed a wet trend, except for a drought trend in northeast of Yunnan Province. Annual and seasonal drought frequency was more higher in Northwest, Southwest and Southeast of Yunnan Province; the heavy drought frequency was very prominent in annual, spring, summer and autumn in Center and East of Yunnan Province; the extreme drought frequency in the annual, summer and autumn was very prominent in Northeast of Yunnan Province; there was very prone to drought in Center and Northeast of Yunnan Province in spring; the frequency of heavy drought was more higher in Central of Yunnan Province and the extreme drought was very likely to occur in Northwest, Southwest and Northeast of Yunnan Province in winter. The annual and seasonal flood frequency was more prominent in West and Southeast Yunnan Province; the heavy and extreme flood frequency was very prominent in southwest of Yunnan Province in annual; the frequency of heavy flood was more prominent in Southwest and central of Yunnan Province and extreme flood occurred in Central and Southeast of Yunnan Province in spring; the frequency of heavy and extreme flood was more higher in northwest of Yunnan Province in summer; the frequency of heavy flood was more higher in Northwest and extreme flood more higher in Southeast of Yunnan Province in autumn; the frequency of heavy flood was more prominent in Southeast and extreme flood in Northwest of Yunnan Province in winter.
Key words：Yunnan Province; RDI index; Spatial and temporal characteristics; Drought and flood change trend