Abstract. Precipitation changes in the Three Gorges Reservoir
Region (TGRR) play a critical role in the operation and regulation of the
Three Gorges Dam (TGD) and the protection of residents and properties. The
potential impacts of the TGD on local and regional circulation patterns,
especially the precipitation patterns, have received considerable attention
since its construction. However, how the moisture transport affects
precipitation changes in the TGRR spatially and temporally remains obscure.
In this study, we investigate the long-term moisture sources of
precipitation and their contributions to precipitation changes over
the TGRR using an atmospheric moisture tracking model. Results suggest that
although there is seasonal variation, the moisture contributing to the TGRR
precipitation primarily originates from the areas southwest of the TGRR
dominated by the Indian summer monsoon. In particular, the sources with the
highest annual moisture contribution are the southwestern part of the
Yangtze River basin and the southeastern tip of the Tibetan Plateau (TP). On average, 41 %, 56 %, and 3 % of the TGRR precipitation originates from ocean, land, and local recycling, respectively. In addition, the decreased precipitation over the TGRR during 1979–2015 is mainly attributed to the significantly decreased moisture contribution from the source regions southwest of the TGRR (especially around the southeastern tip of the TP). Compared to dry years, the higher precipitation in the TGRR during wet years is contributed by the extra moisture from the southwestern source regions that is delivered by the intensified southwesterly monsoon winds.