Tibetan Plateau uplift intensified aridity in inland Asia: The role of the dust-ice cloud interaction feedback mechanism

Abstract

Geological evidence and numerical simulations indicate that the uplift of the Tibetan Plateau (TP) contributed to the formation of inland Asian deserts, and that the dust activity of the deserts affected local atmospheric circulation and the hydrological cycle through dust-radiation interactions. In this study, we conducted a series of sensitivity experiments using a global climate model to evaluate the impact of three forcing factors–TP terrain, dust direct effect, and dust-ice cloud interaction–on the climate evolution of inland Asia. The results show that TP uplift has a significant impact on drought in inland Asia (−175.5 ± 44.1 mm per year) by blocking water vapor transport from westerly winds through the plateau's dynamical effect throughout the year and inducing compensatory downdrafts due to the plateau's thermal effect in summer and autumn. The dust effect intensifies the regional drought by −27.7 ± 30.7 mm per year (particularly in spring and summer), mainly by suppressing atmospheric vertical convection through altering cloud microphysical processes. Our results suggest that the dust-ice cloud interaction provides a positive feedback mechanism for inland Asian aridity induced by the TP uplift.