Fig. 3: Changes in simulated and scaled Hadley cell intensity.
JJA average (a), and DJF average (b) ensemble mean percentage changes in winter simulated Hadley cell intensity, scaled HC intensity based on Held13,15, and the effect from each component on the right-hand side of the Eq. 2 under RCP8.5, GLENS, GEQ, Solar3x3, Solar1x1 ensemble mean (during 2075–2095) and GEOHEATS ensemble mean relative to the baseline ensemble mean (RCP8.5 runs during 2010–2030), respectively. The HC intensity scaling depends on subtropical tropopause height (TROPZ), meridional potential temperature gradient (MTG), and tropical static stability (TSS). To isolate the effect of one component in a perturbation, the other components are set to the baseline values in Eq. 2. Error bars represent standard error. HC intensity is defined as the vertical average of the maximum zonal mean ψm between 900 and 200 hPa, see Nguyen et al.57 for details on the calculation. Since the winter HC is stronger than summer, we only focus on changes in the winter HC intensity, for both hemispheres. Therefore, the analyses are performed on DJF for the Northern Hemisphere and JJA for the Southern Hemisphere separately.
