资源环境科技发展态势分析平台

The responses of cloud and diagnostic fields to the poleward shift of the local Hadley cell subsiding edge are examined using observational and reanalysis data from December 1982 to February 2016. Over the western North Pacific, the interannual variability of the local Hadley cell subsiding edge is marked by an anomalous rising motion, decreased large-scale static stability, and corresponding increases of the midlevel cloud fraction over the climatological sinking zone around 35 degrees N. The most sensitive cloud type is identified to be cumulus congestus, with cloud top pressures in the range of 440-680 hPa and optical thicknesses in the range of 23-60. This kind of cloud is estimated to be the main contributor to the net negative top-of-atmosphere radiation anomaly and to constrain the distribution of the anomalous precipitation associated with the local HC expansion.

Plain Language Summary The Hadley circulation is a dominant large-scale circulation that robustly impacts the variability of global and regional climate. The current scientific consensus is that a poleward shift of the Hadley circulation is underway due to the warming climate; however, the magnitude of the shift, the detailed responses of cloud fields, and the underlying mechanisms still need further elucidation. The present study aims to figure out the most responsive cloud type that varies in conjunction with the poleward shift of the local Hadley cell subsiding edge (LHCSE), especially over the western North Pacific in winter. We explored how the interannual variability of the LHCSE modulates the environmental variables that influence cloud formation and how clouds in turn constrain the precipitation pattern over the northeast Asian coastal area.