Evaluation of Four Methods for Estimating monthly Potential Evapotranspiration (PET) for a Semi-Humid Region in Algeria: A Case Study of Staoueli zone

Abstract

Evapotranspiration is a critical factor in the water balance. However, it is unclear how climate drivers affect its two main components: transpiration and soil evaporation, across the global land surface. This paper uses a well-validated, process-based model to estimate transpiration and soil evaporation [1]. Soil evaporation and transpiration from plants represent the combined evaporation from the soil surface and are not well understood or frequently measured. Actual evapotranspiration is influenced by climatic factors but is constrained by the available moisture in the soil. In contrast, potential evapotranspiration refers to the amount of water that would be lost from a surface completely covered with vegetation if there is sufficient water in the soil at all times for the use of the vegetation. This is solely dependent on climate.     [2] 

Four formulas have been developed to estimate potential evapotranspiration. The objective of this study is to assess methods for estimating evapotranspiration in a sub-humid region, followed by calibration and validation of the most effective method. To achieve this, we utilized a dataset of climate variables, such as temperature, relative humidity, precipitation, sunshine duration, wind speed, and measured evapotranspiration, collected at the Dar El Beida meteorological station from 1990 to 2022 [3]. The methods were compared by evaluating their obtained values with measured evapotranspiration, using various statistical comparison parameters. The findings indicate that the Bouchet model outperforms the other three methods, providing a closer approximation to the measured evapotranspiration.