Seasonal cycle of hemispheric contrast in energy fluxes defined as half the difference in spatial integral of fluxes in the SH minus that in the NH. The solid lines are the observations and the shaded region represents ±1 standard deviation about the CMIP3 PI ensemble average. The terms are defined in the legend and discussed in the text in reference to Eq. (5). The first four terms in the legend sum to yield AHT_{EQ}.

Seasonal cycle of hemispheric contrast in energy fluxes defined as half the difference in spatial integral of fluxes in the SH minus that in the NH. The solid lines are the observations and the shaded region represents ±1 standard deviation about the CMIP3 PI ensemble average. The terms are defined in the legend and discussed in the text in reference to Eq. (5). The first four terms in the legend sum to yield AHT_{EQ}.

The summer hemisphere absorbs more shortwave radiation in the atmospheric column than the winter hemisphere and, in the absence of compensating energy fluxes, would result in a 7.1-PW seasonal amplitude of AHT_{EQ} with northward heat transport peaking near (5 days after) the austral summer solstice. However, 46% of this interhemispheric energy contrast is balanced by air–surface energy exchange (?SHF?) with the atmosphere warming the ocean in the summer hemisphere and the ocean heating the atmosphere in the winter hemisphere. Additionally, 16% of the seasonal variations in ?SWABS? is radiated to space as an interhemispheric contrast in OLR (?OLR?). Both ?SHF? and ?OLR? are nearly antiphased with the insolation and ?SWABS? (with a phase lead of 1 day and phase lag of 12 days, respectively). The interhemispheric contrast of atmospheric energy storage (?STOR_{ATMOS}?) has a seasonal amplitude of 2.3 PW and is associated with the heating (in the extratropics) and moistening (in the tropics) of the atmospheric column in the summer hemisphere and the cooling and drying of the column in the winter hemisphere. It leads the insolation by approximately 60 days, which is expected from a system where the negative feedbacks (OLR and atmospheric heat transport) are substantially stronger than the thermal inertia (Donohoe and Battisti 2012). As a consequence, the sum of all the other energy fluxes, which is equal to AHT_{EQ} by Eq. (5), is substantially smaller than ?SWABS? (due to the damping by ?SHF? and ?OLR?) and lags the insolation (due to the phase lead of atmospheric energy storage, ?STOR_{ATMOS}?); AHT_{EQ} has a seasonal amplitude of 2.2 PW and lags the insolation by 46 days.

## 3) The new quantitative matchmaking ranging from ITCZ place and you may atmospheric temperature transport across the equator

Figure 3 suggests that the ITCZ location (P_{Penny}) covaries with the atmospheric heat transport across the equator (AHT_{EQ}) with a 1-PW change in AHT_{EQ} corresponding to a 2.7° meridional shift in the ITCZ location. _{EQ} is ?0.1 PW and that the maximum value of AHT at all latitudes is on the order of 5 PW (Trenberth and Caron 2001). This quantitative relationship suggests that modest shifts in tropical precipitation must be accompanied by fairly substantial perturbations to the interhemispheric energy budget (Fig. 2), the focus of this manuscript. _{Cent} and AHT_{EQ}?

## We have now ask which matter: What actual processes put the new quantitative dating anywhere between P

(top) Scatterplot of AHT_{EQ} vs the mass overturning streamfunction at 500 hPa over the equator over the seasonal cycle in the observations. Each asterisk is a monthly average and the dashed line is the linear best fit. (bottom) Scatterplot of the location of the 0 mass overturning streamfunction ?_{?=0} at 500 hPa vs AHT_{EQ} (red asterisk and linear best fit dashed line) and P_{Penny} vs AHT_{EQ} (blue asterisk and linear best fit dashed line). The expected relationship between ?_{?=0} and AHT_{EQ} from Eq. (9) is shown by the dashed black line.