The spatial and temporal distributions of potential evapotranspiration in China from 1901 to 2013

This study aims to analyze the changes of potential evapotranspiration (PET) in China during the period 1901 2013. The spatial and temporal distributions of PET in China are developed and analyzed based on CRU data (Climatic Research Union, at 0.5°×0.5° resolution). The entire time series was divided into three periods (1901 1953, 1954 1983 and 1984 2013). Results indicate that: 1) Mean PET (averaged from 1901 to 2013) is highest in northwestern China, followed by the northern, eastern and southwestern areas, with lowest mean PET values encountered in northeastern regions 2) Annual PET has exhibited reducing trend after a substantial increase during the first 53 years. PET during 1949, 1954, 1964 and 1976 were significantly lower than other years, with 2004 and 2009 exhibiting the highest PET values. 3) The difference of mean PET between different climate conditions indicate that PET exhibits significant changes in North China, Central China and East China. 4) Seasonal PET in different climate conditions shows the following: PET in summer has the largest contribution to annual PET, followed by spring, autumn and winter. In 1954 1983, PET values are the lowest of each region in spring, summer and autumn.