The Role of Local Moisture Recycling Evaluated Using Stable Isotope Data from over the Middle of the Tibetan Plateau during the Monsoon Season

Both meteorological data and stable isotope data were used to investigate the role that local moisture recycling plays in maintaining moist land surface conditions over the middle of the Tibetan Plateau during the summer monsoon season. Past studies have shown that precipitation events of the summer monsoon season can be categorized according to synoptic conditions as east-migrating trough types, heat low types, and regional circulation types. Precipitation events during an intensive observation period from 13 to 27 August 2004 were therefore classified into these three types. The contributions of locally recycled moisture in each precipitation type were investigated using isotopic features. The isotope data include precipitation, near-surface atmospheric moisture, and evapotranspiration. First, using a simple Rayleigh distillation model, the isotopic content of the moisture source of the rainfall was estimated from observed precipitation isotope data. The contribution of lower-atmospheric moistu...