Arid Zone Research ›› 2022, Vol. 39 ›› Issue (3): 745-753.doi: 10.13866/j.azr.2022.03.08

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Analysis of change and causes of evaporation for the Shiyang River Basin during the past 60 years

LI Xiaoqin1(),RAN Chen2,ZHANG Xiaoxia3,RAN Xinmin4()   

  1. 1. Lanzhou Resources & Environment Voc-Tech University, Lanzhou 730050, Gansu, China
    2. Zhejiang Institute of Hydraulics & Estuary, Zhejiang Institute of Marine Planning and Design, Hangzhou 310000, Zhejiang, China
    3. Nine-Year School of Chengguan Zhouqu, Zhouqu 746300, Gansu, China
    4. School of Resources and Environment, Lanzhou University, Lanzhou 730000, Gansu, China
  • Received:2021-10-12 Revised:2021-12-30 Online:2022-05-15 Published:2022-05-30
  • Contact: Xinmin RAN E-mail:949038385@qq.com;xmran@lzu.edu.cn

Abstract:

Evaporation is an essential component in hydrological processes, and understanding the change and causes of evaporation is of importance for sustainable management of water resources. Based on the four selected meteorological stations, Wushaoling, Yongchang, Wuwei and Minqin, of which ranged along the altitudinal gradient from 1958 to 2017, the study analysed the change of evaporation and its causes based on the modified PenPan model for the Shiyang River Basin. The results shown that (1) the spatially variation of evaporation can attribute to the altitude effects, namely the evaporation decreased with a rate of 38 mm for every 100 m elevation increase, and temporally change has the significant stage differentiation features, i.e. decreased in 1958-1970, whereas increased after 1970, that particularly obvious in the plain areas of low elevation but not in mountainous area; (2) there was a good agreement with the R2 greater than 0.85 between the observed evaporation and calculated by the modified PenPan model whether in daily or monthly time-scale, however, the wind speed function need amend further in order to obtain the robust performance; and (3) the yearly change of radiative component was relatively stable, but the aerodynamic component of evaporation increase fluctuated, of which was in consistent with the change of temperature and vapor pressure deficit, suggest that the rised temperature is the major reason for the increase of evaporation in Shiyang River Basin after 1970. The result means that the evaporation will increased under climate warming, it will impose more stress on the water resource sustainable management in the future.

Key words: evaporation, PenPan model, component spliting, Shiyang River Basin