Causes of changes in actual evapotranspiration and terrestrial water storage over the Eurasian inland basins

Abstract

The climate of the Eurasian inland basins (EIB) is characterized by limited precipitation and high potential evapotranspiration, making water storage in the EIB vulnerable to global warming and human activities. There is increasing evidence regarding varying trends in water storage across different regions; however, a consistent conclusion on the main attributes of these trends is lacking. Based on the hydrological budget in a closed inland basin, the main attributes of changes in actual evapotranspiration (AET) and terrestrial water storage (TWS) were identified for the EIBs and each closed basin. In the EIB and most of its closed basins (13/16), the TWS and AET showed significantly decreasing and non-significant increasing trends, respectively. The primary cause underlying the significantly decreasing TWS in the EIB was the increase in AET. Approximately 70% of the increase in AET was attributed to increased irrigation diversions from groundwater and glacial melt runoff. At the basin scale, similar to the EIB, changes in AET were the predominant factor driving changes in TWS in most basins, with the exception of the Balkhash Lake basin (BLB), Iran inland river basin (IIRB), Qaidam basin (QB) and Turgay River basin (TuRB). In these basins, changes in precipitation largely contributed to the TWS changes. The AET consumption of other water resources was the main factor contributing to AET changes in seven of the 16 basins, including the Aral Sea,

Evaluation of remotely sensed global evapotranspiration data from inland river basins

“…According to the water source consumed by ET, the change in ET was attributed to changes in precipitation and consumption of other water supply sources. It can be described as (Liu, 2022): $$$$ \Delta \mathrm{ET}=\Delta P+\Delta \mathrm{Others} $$$$ …”

“…According to the water source consumed by ET, the change in ET was attributed to changes in precipitation and consumption of other water supply sources. It can be described as (Liu, 2022):…”

Trends of terrestrial water storage and actual evapotranspiration in Chinese inland basins and their main affecting factors

“…According to the hydrological budget in an inland basin, the difference between precipitation and AET corresponds to the variation in water storage in the basin; therefore, the monthly AET in the basin can be simulated as (Liu, 2022):…”

“…Based on the water source consumed by the AET, AET variation is attributed to alterations in precipitation and the consumption of other water supply sources. It can be calculated as follows (Liu, 2022):…”

“…Inland basins, also referred to as endorheic basins, are defined as regions where runoff in the basin has no direct hydraulic connection with the ocean (Liu, 2022). Thus, inland river basin runoff is isolated from the ocean and eventually enters inland lakes or is absorbed by evapotranspiration.…”