Advantages of the E-CMRSET model in unveiling evapotranspiration water consumption patterns in the inland river basin

Abstract

Vegetation serves as a critical link between the hydrosphere, biosphere, and atmosphere, playing a vital role in the terrestrial water cycle. In arid and semi-arid regions, soil moisture stands out as the primary factor regulating evapotranspiration. Over the past two decades, the comprehensive management project in the Tarim River Basin (TRB, a typical case of an inland river basin in an arid area) has induced substantial changes in the underlying surface, marked by a significant increase in vegetation cover. This shift has the potential to escalate evapotranspiration, intensifying water-related challenges in the region. To assess landscape-scale evapotranspiration in TRB, we employed the enhanced CSIRO MODIS Reflectance-based Scaling EvapoTranspiration model (E-CMRSET), incorporating vegetation changes and soil moisture dynamics as new components. Our analysis delved into evapotranspiration variations across different vegetation types within the TRB. Subsequently, we evaluated the impact of these vegetation changes on regional-scale water consumption patterns. Comparative validation results highlight the superior overall performance of the E-CMRSET model in the TRB when compared to the original CMRSET model, ERA5-Land, PMLV2, EB-ET, and MOD16A2. Vegetation-induced alterations have significantly reshaped the spatiotemporal pattern of evapotranspiration. Notably, the expansion of farmland emerges as the primary contributor to the heightened basin-wide evapotranspiration. Areas surrounding artificial oases witness flourishing vegetation, resulting in a noteworthy increase in water consumption. In contrast, regions distant from human activity zones experience substantial reduction in vegetation, exacerbating encroachments on ecological water usage. Our research contributes valuable insights that can inform models and decision-making processes related to evapotranspiration in arid and semi-arid regions.