Fig. 4: Hysteresis of AMOC, interhemispheric thermal contrast, and ITCZ meridional position.
From: Hemispheric asymmetric response of tropical cyclones to CO2 emission reduction
Ensemble-mean changes of the Atlantic sector meridional overturning circulation (unit: Sv) averaged over a 31-year window centered on the (a) P1 and (b) N3 time slices of the CESM2 IRCC experiment relative to the present-day control simulation. (c) is the difference between (b) and (a). Only values exceeding the 90% confidence level are shaded. CESM2 ensemble-averaged time series of changes in (d) AMOC strength (unit: Sv), (e) interhemispheric surface temperature contrast (unit: K) in the tropical band (30°S-30°N), and (f) centroid (uint: latitude degree) of the ITCZ relative to the present-day control simulation (shown in parentheses at the top of each plot). The AMOC strength is defined as the maximum value of the meridional overturning stream function at 1000 m depth and between 35°and 45°N (indicated by vertical green dashed lines in (a–c). The ITCZ is defined as the latitude that equally divides the annual zonal averaged tropical (20°S-20°N) precipitation. The red and blue colors in (d–f) represent the decarbonization phases of the ZEC and IRCC experiments, respectively, while the gray line represents their common ramp-up period. Colored shading represents two standard deviation spreads between the members.
