Thesw two paragraphs are repeated from Main Text Results 3.1 so that this figure text can be interpreted independently.
We conditionally sort GISS-E2.1+MERRA2u/v into times of nonAR, matureAR, and ARgenesis. Supplemental Figure 1a shows the out-of-ocean LHF difference between the ARgenesis times and nonAR times; Supplemental Figure 1b shows this difference for AllAR times versus nonAR times. NonAR events have ~30-70 W/m2 greater heat flux out of the ocean in the extra-tropics than AllARs (Supp. Fig 1). This pattern holds during ARgenesis, but the difference is greater for AllARs (Supp. Fig. 1a versus Supp. Fig. 1b). There is a clear transition from negative to positive differences at ~20°. However, the fraction of time of the year the tropics have as ARs is very small (Fig. 2a, b). The pattern here is highly consistent with what is known of ARs: they are a principal conduit for poleward heat transportation (Shinoda et al., 2019; Sodemann & Stohl, 2013).
Next, we focus on spatial patterns of LHF differences. NonAR events have ~30-70 W/m2 greater heat flux out of the ocean in the extra-tropics than AllARs (Supp. Fig 1). This pattern holds during ARgenesis, but the difference is greater for AllARs (Supp. Fig. 1a versus Supp. Fig. 1b). There is a clear transition from negative to positive differences at ~20°. However, the fraction of time of the year the tropics have as ARs is very small (Fig. 2a, b). The pattern here is highly consistent with what is known of ARs: they are a principal conduit for poleward heat transportation (Shinoda et al., 2019; Sodemann & Stohl, 2013).