Research Article Open Access

Evaluating Methods of Estimation and Modelling Spatial Distribution of Evapotranspiration in the Middle Heihe River Basin, China

Chuanyan Zhao, Zhongren Nan and Guodong Cheng

Abstract

Seven models commonly used to estimate the daily reference evapotranspiration (ET0) were evaluated in the middle Heihe River Basin of the arid northwestern part of China. The objectives of the study are to choose the appropriate model for estimating the areal distribution of ET0 and to explain the spatial-temporal distribution of the same through GIS in the study area. The results indicated that the FAO-Penman model is the best way to estimate ET0; its RMSE ranged from 1.11 to 1.70 mm, and r2 from 0.59 to 0.93. The spatial variations of ET0 are higher in the western part than in the middle-eastern part of the study area. The temporal variations of daily differences in ET0 rates are mainly due to the differences in irradiance (Rn) and to daily differences in the vapor pressure deficit (D). The spatially modeled ET0 results (r2 = 0.88) are in agreement with the corresponding data in situ on the 15th of each month.

American Journal of Environmental Sciences
Volume 1 No. 4, 2005, 278-285

DOI: https://doi.org/10.3844/ajessp.2005.278.285

Submitted On: 2 February 2006 Published On: 31 December 2005

How to Cite: Zhao, C., Nan, Z. & Cheng, G. (2005). Evaluating Methods of Estimation and Modelling Spatial Distribution of Evapotranspiration in the Middle Heihe River Basin, China. American Journal of Environmental Sciences, 1(4), 278-285. https://doi.org/10.3844/ajessp.2005.278.285

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Keywords

  • Reference crop evapotranspiration
  • Heihe River Basin
  • FAO-Penman equation
  • temporal - spatial variation
  • geographical information system