Resources Science ›› 2020, Vol. 42 ›› Issue (5): 907-919.doi: 10.18402/resci.2020.05.09

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Climate explanation of the potential evapotranspiration changes in Weihe River Basin

GUO Mengyao1, SHE Dunxian1,2(), ZHANG Liping1,2,3, TANG Rouxin1, ZHAO Pengyan1   

  1. 1. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China;
    2. Hubei Provincial Key Laboratory of Water System Science for Sponge City Construction, Wuhan 430072, China;
    3. Huanggang Normal University, Huanggang 438000, China
  • Received:2018-11-19 Revised:2019-06-16 Online:2020-05-25 Published:2020-07-25
  • Contact: Dunxian SHE E-mail:shedunxian@whu.edu.cn

Abstract:

Analyzing the changes in potential evapotranspiration (ET0) and the attribution is an important way to understand hydrologic process and its response to climate change. In this study, after applying the FAO Penman-Monteith equation to estimate the ET0 in the Weihe River Basin for the period of 1960-2016, the differential method was employed to quantify the contribution of the four meteorological factors, i.e. solar radiation (Rs), wind speed (u2), relative humidity (RH), and average temperature (T), to the ET0 changes. The main results are shown below. During the 57 years, annual ET0 showed a slightly increasing trend of 0.239 mm/a, and multi-year average annual ET0 increased from the west to the east and from the south to the north of the basin spatially. We found that annual ET0 was most sensitive to RH, followed by Rs and T, and least sensitive to u2. Moreover, the sensitivity coefficients of T and u2 decreased with increasing elevation. From the perspective of contribution, the changes in T contributed most to the changes of annual ET0, followed by u2 and RH, and the changes in Rs showed the smallest contribution to annual ET0 changes. Generally speaking, the negative effects caused by the decrease in Rs and u2 to annual ET0 changes were offset by the positive effects caused by the increase in T and decrease in RH, which finally resulted in the increasing trend in annual ET0 during 1960-2016 in the whole basin. Since the correlation among the meteorological factors may influence their individual contribution to ET0 changes, we can fully discuss the attribution of ET0 changes by considering the interactions between these factors in practice. This study is significant for understanding the influence mechanism of climate change to hydrologic cycle as well as improving our capacity to cope with climate change regionally.

Key words: potential evapotranspiration, climate change, meteorological factor, sensitivity coefficient, total differential method, attribution analysis, Weihe River Basin