Precipitation recycling ratio and water vapor sources on the Tibetan Plateau

Precipitation recycling ratio(i.e.,evaporation-precipitation feedback strength)and water vapor sources are two key aspects of regional water cycle,and their quantification is essential for understanding water cycle processes and their changes.The results of existing studies on the precipitation recycling ratio and water vapor sources for the Tibetan Plateau were highly controversial.This article clarifies different frameworks for understanding the water cycle.It points out that(1)the ratio of evaporation to precipitation depends mainly on climate regimes,while the precipitation recycling ratio is closely related to both the climate regimes and the scale of the region of interest,and(2)the water vapor sources depend on the traced period(precipitating or non-precipitating period)and the degree of tracing.Within the same theoretical framework,there is no fundamental conflict among the results of different studies on the water cycle in the Tibetan Plateau.