Slowdown and reversal of terrestrial near-surface wind speed and its future changes over eastern China

A recovery of near-surface wind speed (SWS) in the last decade has been reported over China; nevertheless, the contributions of large-scale ocean-atmosphere circulations (LOACs) to the SWS changes are rarely investigated. In this study, the turning point (TP) of the terrestrial stilling was validated over eastern China for 1979–2017. Furthermore, a forward stepwise regression algorithm was used to assess the contribution of LOACs to SWS changes. The results revealed that the TP of the SWS reversal occurred in approximately 2011 during the study period. Mean annual and seasonal SWSs exhibited decreases before the TP, with the largest decrease in spring (–0.134 ± 0.014 m s⁻¹ decade⁻¹), while SWSs increased after the TP, most strongly in autumn (0.377 ± 0.053 m s⁻¹ decade⁻¹). The SWS decrease before the TP and increase after the TP were caused by the decreasing and increasing frequencies of strong windy days (>75th percentile of SWS), respectively. The effects of LOACs on the long-term changes of SWS were pronounced. The contributions of LOACs to the decreasing and increasing trends of SWSs were >60.0%, with the exception of autumn. The projected SWSs exhibited increases in the near-term (2021–2040) for the low-emission scenarios (e.g. Shared Socioeconomic Pathway 245). For the mid-term and long-term projections, the SWSs still displayed a downward trend, which was mainly attributed to the reduction of strong windy days. Consequently, the present SWS recovery in the recent decade may be only expected to last for a short amount of time before winds start decreasing again. (letter)