Global Near-Surface Wind Speed Changes over the Last Decades Revealed by Reanalyses and CMIP6 Model Simulations

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  • 1 Regional Climate Group, Department of Earth Sciences, University of Gothenburg, Gothenburg, 40530, Sweden
  • 2 Centro de Investigaciones sobre Desertificación, Consejo Superior de Investigaciones Científicas (CIDE-CSIC), Moncada, Valencia, Spain
  • 3 State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
  • 4 Academy of Disaster Reduction and Emergency Management, Ministry of Emergency Management and Ministry of Education, Beijing Normal University, Beijing 100875, China
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Abstract

Near-surface (10 m) wind speed (NWS) plays a crucial role in e.g. hydrological cycles, wind energy production and air pollution, but what drives their multi-decadal changes is still unclear. Using reanalysis datasets and Coupled Model Inter-comparison Projection Phase 6 (CMIP6) model simulations, this study investigates recent trends in the annual mean NWS. The results show that the northern hemisphere (NH) terrestrial NWS experienced significant (p<0.1) decreasing trends during 1980–2010, when the southern hemisphere (SH) ocean NWS was characterized by significant (p<0.1) upward trends. However, during 2010–2019, global NWS trends shifted in their sign: NWS trends over the NH land became positive, and trends over the SH tended to be negative. We propose that the strengthening of SH NWS during 1980–2010 was associated with intensified Hadley cell over the SH, while the declining of NH land NWS could have been caused by changes in atmospheric circulation, alteration of vegetation/land-use and the accelerating Arctic warming. The CMIP6 model simulations further demonstrate that the greenhouse gas (GHG) warming plays an important role in triggering the NWS trends over the two hemispheres during 1980–2010 through modulating meridional atmospheric circulation. This study also points at the importance of anthropogenic GHG forcing and the natural Pacific Decadal Oscillation to the long-term trends and multi-decadal variability in global NWS, respectively.

Corresponding author address: Prof. Deliang Chen, University of Gothenburg. Box 460, 40530 Gothenburg, Sweden. E-mail: deliang@gvc.gu.se

Abstract

Near-surface (10 m) wind speed (NWS) plays a crucial role in e.g. hydrological cycles, wind energy production and air pollution, but what drives their multi-decadal changes is still unclear. Using reanalysis datasets and Coupled Model Inter-comparison Projection Phase 6 (CMIP6) model simulations, this study investigates recent trends in the annual mean NWS. The results show that the northern hemisphere (NH) terrestrial NWS experienced significant (p<0.1) decreasing trends during 1980–2010, when the southern hemisphere (SH) ocean NWS was characterized by significant (p<0.1) upward trends. However, during 2010–2019, global NWS trends shifted in their sign: NWS trends over the NH land became positive, and trends over the SH tended to be negative. We propose that the strengthening of SH NWS during 1980–2010 was associated with intensified Hadley cell over the SH, while the declining of NH land NWS could have been caused by changes in atmospheric circulation, alteration of vegetation/land-use and the accelerating Arctic warming. The CMIP6 model simulations further demonstrate that the greenhouse gas (GHG) warming plays an important role in triggering the NWS trends over the two hemispheres during 1980–2010 through modulating meridional atmospheric circulation. This study also points at the importance of anthropogenic GHG forcing and the natural Pacific Decadal Oscillation to the long-term trends and multi-decadal variability in global NWS, respectively.

Corresponding author address: Prof. Deliang Chen, University of Gothenburg. Box 460, 40530 Gothenburg, Sweden. E-mail: deliang@gvc.gu.se
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