Quantifying the Impacts of Climate Change and Vegetation Variation on Actual Evapotranspiration Based on the Budyko Hypothesis in North and South Panjiang Basin, China

Tiansheng Li,Bojun Liu,Lei Cheng,Dunxian She,Jun Xia,Lei Zou

doi:10.3390/w12020508

Abstract

Actual evapotranspiration (Ea) plays a key role in the global water and energy cycles. The accurate quantification of the impacts of different factors on Ea change can help us better understand the driving mechanisms of Ea in a changing environment. Climate change and vegetation variations are well known as two main factors that have significant impacts on Ea change. Our study used three differential Budyko-type equations to quantify the contributions of climate change and vegetation variations to Ea change. First, in order to establish the relationship between the parameter n, which usually presents the land surface characteristics in the Budyko-type equations, with basic climatic variables and the Normalized Difference Vegetation Index (NDVI), the stepwise linear regression method has been used. Then, elasticity and contribution analyses were performed to quantify the contributions of different numbers of climatic factors and NDVI to Ea change. The North and South Panjiang basin in China was selected to investigate the efficiency of the modified Budyko-type equations and quantify the impacts of climate change and vegetation variations on Ea change. The empirical formal of the parameter n established in this study can be used to simulate the parameter n and Ea for the study area. The results of the elasticity and contribution analyses suggest that climate change contributed (whose average contribution is 149.6%) more to Ea change than vegetation variation (whose average contribution is −49.4%). Precipitation, NDVI and the maximum temperature are the major drivers of Ea change, while the minimum temperature and wind speed contribute the least to Ea change.

Highlights

Driven mainly by solar radiation, terrestrial actual evapotranspiration (Ea ) plays a key role in the water and energy exchange between land surface and atmosphere
In the context of global change, the accurate quantification of Ea and identification of different factors that influence Ea change are crucial for evaluating the impacts of changes in
The three Budyko-type equations proposed by Fu [35], Zhang et al [36] and Wang-Tang [37] were selected to investigate the impacts of climate change and vegetation variation on Ea change

Summary

Introduction

Driven mainly by solar radiation, terrestrial actual evapotranspiration (Ea ) plays a key role in the water and energy exchange between land surface and atmosphere. Many studies have indicated significant change in Ea due to climate change based on statistical analyses [1,2,3,4,5]. These findings have increased the interest in investigating the potential climatic driving factors that control the changes in Ea. Some previous studies indicated that the impacts of changes in different climatic factors on Ea change are quite different. Increased cloudiness and decreased solar irradiance can induce reductions in Ea [6]. The decrease in solar irradiance was found to be the main cause of the decline in Ea across many regions of the world [7,8]

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