Cloud Water Resource over the Asian water tower in recent decades

Abstract

The Asian water tower (AWT hereafter) is one of the world's most important, vulnerable, and at-risk regions with abundant water resources in the world. Climate change affects the terrestrial water availability over the AWT, and also the distribution and variation patterns of Cloud Water Resource (CWR hereafter), the water resources with potential precipitation capacity in the atmosphere. The CWR over the AWT is scarce over the Indus basin with a drying trend, while more abundant over the Yangtze and Yellow basins with a wetting trend during 2000–2017, suggesting the “dry gets drier, wet gets wetter” pattern of CWR over the AWT in recent decades. The change of CWR over the AWT can be influenced by dynamic circulation. There is an abnormal high in the Ganges, Brahmaputra, Yangtze, and Yellow basins, caused by the eastward and southward propagation of anomalous wave activity flux generated by surface sea temperature anomalies over the North Atlantic. Moreover, the anticyclone is favorable for transporting cloud water hydrometeors at the higher level, and furnishing water vapor to condense into cloud water hydrometeors influenced by abnormal upward movement at the lower level. While anomalies low and vertical downward movement occurs in the Indus basin to reduce the CWR here. Our results provide prospects for understanding changing CWR and related dynamic circulation at the basin scale over the AWT.