CMIP6 Projected Trend of Winter and Summer Variation in Arctic Cyclones over the 21st Century

Abstract Using the simulation results from the CMIP6 global climate models, we calculate the projected changes of different kinds of Arctic cyclones (ACs)in the 21st century and examine the characteristics related to the Arctic cyclones under two shared socio-economic pathways (SSP1-2.6, SSP5-8.5). There is a significant decline of ACs during winter over southern Greenland, the Barents Sea, and the Gulf of Alaska. The number of Arctic cyclones has a significant circular decrease along the Arctic over most of the continent region in summer. By the end of the 21st century, the proportion of weaker, large-radius, and long-lifespan ACs will increase. The number of extreme Arctic cyclones will decrease in the future. However, the trend in the intensity of Arctic cyclones depends on the measure of cyclone intensity we use. Weaker baroclinic instability in the future is the primary reason for the decline of cyclone density in winter, but the situation in summer is more complicated. The number of Arctic cyclones in summer is affected by various factors like tropopause polar vortex and mid-latitude cyclones entering the Arctic. The positive anomaly of Eady growth rate can also cause the explosive growth of cyclones over the ocean.