Evapotranspiration is an important part of the hydrological process of wetland, which influences the hydrological ecosystem of wetland. Zoige Wetland is taken as the study area. Based on the daily meteorological observation data of 6 meteorological stations 1963-2013 which are within and outside the Zoige Wetland, the potential evapotranspiration (ET0) of each site and the wetland is estimated based on the Penman-Monteith formula recommended by FAO, respectively. The spatial and temporal evolution characteristics of ET0 are analyzed from the perspectives of tendency, mutation and periodicity, and the relationship between ET0 and its main influencing factors is discussed. The result shows that the tendency of seasonal and interannual ET0 in Zoige Wetland is presented as an increasing trend on the time scale, especially in summer, autumn and interannual scale; in terms of spatial scale, it exhibits an increasing trend to varying degrees, and this trend of ET0 is very significant among the whole region in autumn, and run through the east and west in the interannual scale; meanwhile, Zoige Wetland showed a more obvious trend of warming and drying. For the mutation of ET0, the mutation years of spring, winter and annual scale ET0 were all around 2002, while the mutation occurred in summer and autumn around 1988 and 1997, respectively. For the periodicity of ET0, the main period of ET0 in spring, summer, autumn and the interannual scales may be 28 years, and 22 years in winter. In addition, the first major influencing factor of ET0 is temperature in spring, autumn, winter and interannual scales, while the sunshine hours in summer; among different stations, the first one is relative humidity, which are the most obvious in Zoige and Hongyuan stations in winter. The study is expected to provide a scientific basis for further exploring the climate and ecological environment changes in the Zoige wetland.
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