Difference in the atmospheric water cycle over the Hengduan Mountains between wet and dry summers.

The atmospheric water cycle over the Hengduan Mountains (HM) is crucial to the local and downstream ecosystem and social economy, while its characteristics and variability have not been thoroughly revealed yet. Based on a bulk method, the atmospheric water cycle over the HM and its difference between wet and dry summers is analysed in this study. Results show that the summer precipitation recycling ratio over the HM is 11.5% in climatology and is significantly and negatively correlated with precipitation there on interannual timescale. In wet summers, the precipitation recycling ratio decreases by 13% compared to dry summers. The origin of water vapour for precipitation over the HM is mainly contributed by the external water vapour transport (local evaporation) in wet (dry) summers. August is found to have the strongest climatological mean precipitation recycling ratio (15.2%) and atmospheric water cycle among 3 months in summer. Also in August, the difference in precipitation recycling ratio between wet and dry summers is largest. In wet summers, although the increase in the external moisture inflow is the largest in June (3.0 × 107 kg·s−1), the increase of precipitation is the largest in August (2.6 × 107 kg·s−1) due to its stronger atmospheric water cycle. Our study promotes the knowledge of the atmospheric water cycle over the HM and provides a new perspective to understand the interannual variations of the precipitation over the HM. [ABSTRACT FROM AUTHOR]