Non-Synchronization of the Decadal Transition in Winter Near-Surface Wind Speed Across Northern and Southern China

Decadal variations in near-surface wind speed (NSWS) and their causes are poorly understood. We found that the decadal transition of winter NSWS in northern China (NC) was 10 years earlier than in southern China (SC), which could be linked to the changes in intensities of the eastward wave-activity flux and Siberian High (SH) induced by the Warm Arctic-Cold Eurasia (WACE) dipole pattern. From 1973 to 1990, the WACE pattern from positive to negative phases confined the eastward wave trains to high latitudes with a decreasing SH, inducing an NSWS reduction. From 1991 to 2000, the WACE strengthened from negative to positive phases, causing a decadal transition in NSWS first in NC. After 2000, accompanied by the strengthening of the positive WACE, the eastward wave trains propagated downstream to lower latitudes, the SH and the meridional pressure gradient enhanced. Therefore, the transition of decadal NSWS occurred in SC until 2000. Near-surface wind speed (NSWS) is critical in exchanging energy, water, and momentum between the Earth's surface and the lower atmosphere. Previous studies have reported that the slowdown in NSWS and its reversal could be a manifestation of decadal variations in the climate system. However, the regional non-synchronization of decadal variations in NSWS and the corresponding cause are poorly understood. This study reported a non-synchronization of the decadal transition in winter NSWS between northern China (NC) and southern China (SC). The significant turning point of winter NSWS across NC was 10 years earlier than those across SC, and it was caused mainly by the zonal wind. The non-synchronization of decadal variations in winter NSWS between NC and SC was linked to the Warm Arctic-Cold Eurasia (WACE) atmospheric circulation pattern, and the Siberian High (SH) could serve as a bridge through which the WACE atmospheric circulation pattern influences the asynchronous transition of decadal NSWS between NC and SC. This study improves the understanding of decadal variations in NSWS across China. The decadal near-surface wind speed (NSWS) transition in winter over northern China (NC) was 10 years earlier than in southern China (SC) The non-synchronization of the decadal transition in NSWS between NC and SC was linked with the Warm Arctic-Cold Eurasia pattern Intensities of wave-activity flux and Siberian High influenced the non-synchronization of decadal transition in NSWS between NC and SC