Spatiotemporal changes in the seasonality of terrestrial wind speed

Abstract:

Since the reversal of global terrestrial wind speed was reported at an annual scale, there has been no study on the spatiotemporal changes in the seasonality of wind speed (i.e. monthly wind speed (MWS)) during the past four decades, understanding which will help optimize the utilization of wind resources. Here we analyzed annual maximum MWS and annual minimum MWS as well as their difference (i.e. the range of MWS), achieved by in-situ 10 m wind speed at the meteorological stations that have continuous monthly wind records during 1980-2018 from a global sub-daily dataset (HadISD). Globally, for all the 12 months, the average MWS in the northern hemisphere fell first and then reversed during the last four decades, while those in the southern hemisphere kept rising. Interestingly, we find a continuous narrowing range of MWS at a global scale, in many regions including Europe, Asia and southern hemisphere, and 74.2% of the individual stations. This phenomenon is mainly due to maximum MWS decreasing more than minimum MWS during the stilling period and minimum MWS increasing more than maximum MWS during the recovery period in the northern hemisphere; while in the southern hemisphere, both maximum and minimum MWS were increasing but the increase in minimum MWS is more than that in maximum MWS. Large-scale ocean-atmosphere oscillations may contribute to these phenomena, however neither ERA5 nor AMIP6 and CMIP6 models can reproduce these phenomena. Improving the simulation of the observed changes in the seasonality of terrestrial wind speed in the reanalysis and the models may help to improve the capacities of these models in predicting future wind speed changes.