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Long-range transport of black carbon from South Asia to the Tibetan plateau and its deposition on glaciers directly enhances glacier melt. Here we find South Asian black carbon also has an indirect effect on the plateau's glaciers shrinkage by acting to reduce the water supply over the southern Tibetan plateau. Black carbon enhances vertical convection and cloud condensation, which results in water vapor depletion over the Indian subcontinent that is the main moisture flux source for the southern Tibetan plateau. Increasing concentrations of black carbon causes a decrease in summer precipitation over the southern Tibetan plateau, resulting in 11.0% glacier deficit mass balance on average from 2007 to 2016; this loss rises to 22.1% in the Himalayas. The direct (accelerated melt) and indirect (mass supply decrease) effects of black carbon are driving the glacial mass decline of the so-called "Asian Water Tower". South Asian black carbon's pairing activities (direct and indirect effects) are driving glacial mass decline of the so-called "Water Tower of Asia" with the potential to threaten future water resources for the countries that rely upon its source. [ABSTRACT FROM AUTHOR]

This study investigates the modulation of the South Asian high's (SAH) intensity variation on the persistent heavy rainfall (PHR) and heat wave (HW) events over the Asian summer monsoon regions during summer 1979–2013. The first mode of an empirical orthogonal function (EOF) analysis performed on standardized subseasonal anomalies at 200‐hPa geopotential height over the SAH's main body (20°–5°N, 35°–110°E), reveals the intensity variation of the SAH with a 10–40‐day periodicity. The strengthening (weakening) of the SAH's main body is accompanied by negative (positive) outgoing longwave radiation (OLR) anomalies and more (less) anomalous rainfall over the Indian subcontinent, southern foot of Tibetan Plateau (TP) and subtropical East Asia. Using different thresholds, the proportion for modest PHR events is approximately 30% and can reach up to 40–50% for extreme PHR events during the strong phase of SAH. About 20% of modest PHR events and only 10% of extreme PHR events occur under the weak phase of SAH, suggesting that SAH has a more significant impact on the occurrence of extreme PHR events over the south and East Asian regions. In contrast, HW events associated with strong SAH account for approximately 5–10% whereas an increased occurrence of HW events is observed during the weak phase of SAH with a ratio up to 15–20%. A much more intensified updraft flow, enhanced cross‐equatorial moisture flux and western North Pacific moisture flux is accompanied with strong SAH, which provide favourable conditions for occurrence of extreme PHR events, leading to less surface solar radiation anomalies. The mirror image is seen in the weak SAH phase, contributing to the decrease of extreme PHR events and increase of HW events. The above analysis indicates that the SAH provides significant modulation and impact on extreme rainfall and temperature events over the Asian monsoon regions on subseasonal timescale. [ABSTRACT FROM AUTHOR]