Climate response to tropical cyclone-induced ocean mixing in an Earth system model of intermediate complexity

We introduce a parameterization of ocean mixing by tropical cyclones (TCs) into an Earth system model of intermediate complexity. The parameterization is based on previously published global budgets of TC-induced mixing derived from high-resolution satellite measurements of anomalous sea surface temperatures along storm tracks. Recognizing the caveats introduced, for example, by the simplified model structure, we find that the representation of realistic TC-induced mixing substantially alters the equilibrium conditions of (1) the thermal structure of the upper ocean, (2) the surface energy budget, and (3) the circulation in the equatorial to subtropical Pacific Ocean. These changes result in warmer upwelling regions in the eastern equatorial Pacific and an overall increase in ocean heat content consistent with the recent TC heat pump hypothesis. Spatial variability in the mixing appears to be a key factor in the modeled response. We find no substantial influence of the considered TC-induced mixing on poleward ocean heat transport in the analyzed model. Our results suggest that climate-sensitive mixing feedbacks are plausible; however, the large-scale effect is mainly confined to the subtropical Indo-Pacific region for present-day TC climatology.