Trends of estimated potential evapotranspiration in the Poyang Lake basin, China

Using the Penman-Monteith method, the potential evapotranspiration (PET) was calculated over the Poyang Lake basin during 1960-2008. Our analysis indicates that except spring, PET in summer, autumn and winter shows long term decreasing trend, with the largest in summer and the least in winter. The decrease of annual PET in the Poyang Lake basin is mostly affected by the decline of summer PET. On catchment scale, although the calculated PET at all the Metero-stations shows decrease trend, the trends are not significant at some stations. Further analysis indicates that the Most important predictor for the decreasing trend in potential evapotranspiration is sunshine duration and wind speed, followed by relative humidity and air temperature.