Projected changes in the interannual variability of surface air temperature using CMIP6 simulations

We investigate the interannual variability of surface air temperature in the twenty-first century using the Coupled Model Intercomparison Project Phase 6 (CMIP6) model data under three shared socioeconomic pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5). Relative to 1961-2014, the interannual variability of annual temperature is projected to increase by 6%, 6%, and 12% globally in the 2051-2100 period under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively, with an average increase of 10-22% in low latitudes and decrease of 3-28% in high-latitude oceans. The spatial pattern of wintertime variability changes is mainly determined by variations in the meridional temperature gradient. Sea ice losses and variations in snow extent in the mid to high latitudes are both related with large variability decreases according to analysis of the underlying surface. In South America and South Africa, the variability enhancement is related to the adjustment of the wet-dry status, while that in South Asia and central Africa depends more on the positive longwave radiative effect due to the increase in clouds. In tropical oceans, the increases in sea surface temperature variabilities and air-sea interactions dominate the enhanced surface air temperature variability.