The reversal of surface wind speed trend in Northeast China: impact from aerosol emissions

A “stilling” or “reversal” of surface wind speed (SWS) trend over the landmass of the Northern Hemisphere has been observed during the past decades, with notable regional disparities. In particular, the reversal of SWS in Northeast China is observed in 2010, which is different to the features over other regions such as North China (reversal in 2006), South China (reversal in 2000), and East China (no reversal). However, the mechanism behind the unique feature of SWS reversal over Northeast China is inadequately understood. Although previous studies generally attributed the reversal of SWS trend to large-scale ocean–atmosphere circulation (LOAC) signals, here we show that the interdecadal decline in local aerosols measured by aerosol optical depth (AOD) also contributes to the reversal of SWS over Northeast China, supported by the results from a sensitivity experiment conducted using Community Atmosphere Model version (CAM) 5.3 and the Detection and Attribution Model Intercomparison Project (DAMIP). Specifically, the aerosol reduction acts to decrease low-level static stability and enhance turbulent kinetic energy (TKE), increasing local SWS. Quantitative analyses indicate that the anthropogenic aerosol reduction plays a dominant role in the observed increasing SWS in the recent decade. Our results emphasize the importance of considering aerosol changes for a comprehensive understanding of SWS changes on regional scales.