Variety Characteristics and Cause Analysis of Potential Evapotranspiration in the Ebinur Lake Basin in Xingjiang

XU Jingjing; JIN Xiaoyan; QIANG Haofan; DAI Hui; LIANG Chuan

doi:10.13522/j.cnki.ggps.2017.0316

Abstract：[Objective]Find the main factor of ET0.[Method]According to the daily meteorological data from 6 representative meteorological stations in the Xinjiang Ebinur Lake Basin from 1960 to 2015, the potential evapo-transpiration(ET0)was calculated by radiation-corrected Penman-Monteith model. The climate tendency rate, Mann-Kendall method and Morlet wavelet analysis were used to analyze the periodic change rule of potential evapotranspiration. Meanwhile, the causes of ET0 change were analyzed by index sensitivity method based on path analysis principle.[Result]The annual average of ET0 in the Ebinur Lake basin from 1960 to 2015 was 956.1 mm with a significant decreasing trend of-29.89 mm/10 a(p<0.001);The ET0 of the four seasons decreased with the sequence of summer>spring>autumn>winter, and the ET0 each season presented a downward trend with year se-quence. The decreasing trend of ET0 was the most significant in summer. The ET0 of summer and spring made the biggest relative contribution to annual values;There was a significant decrease abrupt point of ET0 in 1986 with a decline of 10.52％. ET0 had a strongest intense oscillation in the 28-year period, which was the first major cycle of sequential change, while the second and third main cycles were 15 years and 8 years respectively;The path coeffi-cient of wind speed on ET0 was 0.736, the total contribution to estimate reliability of regression equation was 0.577.[Conclusion]The decrease in wind speed is the main factor for the decline of ET0 in the Ebinur Lake Basin, followed by relative humidity, net radiation, precipitation and maximum temperature.