Articles | Volume 21, issue 2
Research article
14 Feb 2017
Research article |  | 14 Feb 2017

Monitoring the variations of evapotranspiration due to land use/cover change in a semiarid shrubland

Tingting Gong, Huimin Lei, Dawen Yang, Yang Jiao, and Hanbo Yang

Abstract. Evapotranspiration (ET) is an important process in the hydrological cycle, and vegetation change is a primary factor that affects ET. In this study, we analyzed the annual and inter-annual characteristics of ET using continuous observation data from eddy covariance (EC) measurement over 4 years (1 July 2011 to 30 June 2015) in a semiarid shrubland of Mu Us Sandy Land, China. The Normalized Difference Vegetation Index (NDVI) was demonstrated as the predominant factor that influences the seasonal variations in ET. Additionally, during the land degradation and vegetation rehabilitation processes, ET and normalized ET both increased due to the integrated effects of the changes in vegetation type, topography, and soil surface characteristics. This study could improve our understanding of the effects of land use/cover change on ET in the fragile ecosystem of semiarid regions and provide a scientific reference for the sustainable management of regional land and water resources.

Short summary
Seasonal and inter-annual features of ET were analyzed over four periods. A normalization method was adopted to exclude the effects of potential evapotranspiration and soil water stress on ET. During the land degradation process, when natural vegetation (including leaves and branches), sand dunes, dry sand layers, and BSCs were all bulldozed, ET was observed to increase at a mild rate. In a vegetation rehabilitation process with sufficient groundwater, ET also increased at a faster rate.