Improved Subseasonal Prediction of Atmospheric Energy Transport over the Northwest Pacific Using an Atmosphere–Ocean Coupled Model

Abstract Poleward transport of energy is essential for reducing Earth’s energy imbalance. During boreal summer, equatorward dry static energy transport (DSET) and poleward latent heat transport (LHT) are located in the upper and lower tropical atmosphere, respectively. This study investigates changes in meridional atmospheric energy transport and their underlying mechanisms using a global coupled atmosphere–ocean model. In the July 2017 simulations, the coupled model better captures the phase variation of DSET and exhibits a small LHT at 20°N (approximately 1 PW) compared with the standalone atmospheric model. Ocean coupling decreases meridional gradient of ocean skin temperature, which mitigates the poleward propagation of convection. Consequently, the well-established meridional circulation not only increases low-level divergence but is linked to changes in the spatial distribution of moisture. Our results show that ignoring the seasonal variability in ocean temperature can accelerate the hemispheric energy imbalance through the northwest Pacific region.