• 研究报告 •

### 1965—2018年广西西江流域参考作物蒸散量时空演变及其影响因子

1. 1南宁师范大学北部湾环境演变与资源利用教育部重点实验室， 南宁 530001； 2南宁师范大学广西地表过程与智能模拟重点实验室， 南宁 530001； 3南宁师范大学地理科学与规划学院， 南宁 530001）
• 发布日期:2020-05-10

### Spatial and temporal variations of reference evapotranspiration and its influencing factors in Guangxi Xijiang River Basin from 1965 to 2018.

YAN Yan1,2, HUANG Kai-yan1,3, HU Bao-qing1,2, WANG Sheng1,2*, HUANG Yu-qing1,2

1. (1Nanning Normal University, Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Nanning 530001, China; 2Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation, Nanning 530001, China; 3 School of Geography and Planning, Nanning 530001, China).
• Published:2020-05-10

Abstract: Estimation of reference evapotranspiration (ET0) could contribute to revealing water-heat balance and water cycle process and consequently provide reference for the sustainable utilization and exploration of regional water resources. Here, we re-fitted the net shortwave emissivity and calculated ET0 in Guangxi Xijiang River Basin from 1965 to 2018, using improved Penman-Monteith model. The trend analysis and mutation point detection of ET0 were performed by Mann-Kendall method. The spatialtemporal variations of ET0 were analyzed by interpolation with inverse distance weighting method. Factors influencing ET0 were determined based on the contribution rate of meteorological factors. At spatial scale, ET0 presented an increasing tendency with decreasing altitude. The highest ET0 values were mainly distributed in the central part of thebasin, while the lowest values occurred in the edge and slope zone of the YunnanGuizhou Plateau, which lies in the northwest part of the basin. ET0 in spring varied with the longitude, while summer ET0 showed a similar spatial pattern to that of the inter-annual ET0. The mean annual ET0 of the basin was 637.2 mm, with a declining rate of -0.018 mm·a-1. The ET0in spring, summer, winter and autumn were 0.053, -0.053, -0.007 and -0.011 mm·a-1, respectively. ET0 in all the seasons except spring showed an downward trend. The largest increase in ET0 occurred in winter. The importance of dominant factors influencing ET0 of the basin followed an order of relative humidity (with a contribution rate of 39.0%) > average wind speed (27.2%) > sunshine duration > average temperature. Relative humidity negatively affected ET0, with a correlation coefficient of -0.673. Sunshine duration, average wind speed, and average temperature positively affected ET0. The dominant driving factors of ET0 and their contribution rates varied across different parts of the basin.