Long-Term Trends of Northern Hemispheric Winter Cyclones in the Extended ERA5 Reanalysis

Abstract

© 2022. The Authors.Understanding how historical extratropical cyclone tracks respond to global warming is crucial for predicting future storm activity. Thus, long reanalysis data sets are needed to investigate long-term changes in storm features and their impacts. By using a systematic change-point analysis, we provide evidence that the presatellite ERA5 data of the Backward Extension (covering 1950–1978) is highly compatible with the standard ERA5 (1979–2021) data set. The joint ERA5 data from 1950 to 2021 is consistent in all storm-related quantities, consequently allowing long-term studies. Our trend analysis suggests that the intensity of extratropical cyclones has increased significantly during 1950–2021. The number of North Pacific storms has increased, and while they have longer life cycles and travel larger distances, they grow more slowly. For 1979–2021, we find notable increases in wind gusts for North Atlantic storms and in precipitation extremes for North Pacific storms. Our results also indicate an increase in Northern Hemispheric storminess based on an index of an extreme percentile of the central geopotential. Finally, we show potential impact locations using the findings of our trend analysis.