Spatial and temporal variation of monthly rainfall nonuniformity of the upper Yangtze basin

摘要

Apportionment entropy, defined by Shannon's information entropy theory, was applied to analyze the monthly rainfall nonuniformity of the upper Yangtze basin within a year. The spatial variability analysis indicates that the intra-annual monthly apportionment of rainfall is relatively even in Wu sub-basin, while rainfall is relatively aggregate in the lower Jinsha sub-basin and the middle Jialing sub-basin. In temporal domain, the Mann-Kendall method was applied to analyze the change trend of the intra-annual nonuniformity. For 17 meteorological stations, the intra-annual monthly apportionment of rainfall trended to evenness, while that trended to aggregate for only 2 meteorological stations. For the other 29 meteorological stations, no significant change trend of the intra-annual monthly rainfall nonuniformity was observed.