Comparison of mixed-phase clouds over the Arctic and the Tibetan Plateau: seasonality and vertical structure of cloud radiative effects

Abstract

Abundant mixed-phase clouds exist over the Arctic and the Tibetan Plateau. Salient differences in their seasonal cycle and in their vertical structure and cloud radiative effects (CREs, which includes shortwave CRE, longwave CRE and net CRE) imply different influences on the climate system. The maximum incidence of mixed-phase clouds appears during the late spring and early winter over the Arctic Ocean, but it appears during the summer over the Tibetan Plateau. The surface mixed-phase-cloud-induced CRE exerts a strong warming effect over the Arctic during the cold season (from September to May), in contrast to the strong cooling effect over the Tibetan Plateau during the summer. The existence of temperature inversion over the Arctic Ocean confines the mixed-phase clouds and associated cloud hydrometeors and vertical radiative heating profile at the near surface, while over the Tibetan Plateau there is no such a temperature inversion, and hence the cloud-induced atmospheric heating profile exhibits both larger vertical contrast and more seasonal variation over the Tibetan Plateau.