On the Total, Mean, and Eddy Heat and Freshwater Transports in the Southern Hemisphere of a ⅛° × ⅛° Global Ocean Model

The large-scale volume, heat, and freshwater ocean transports in the Southern Hemisphere are investigated\udusing time-averaged output from a seasonless, high-resolution general circulation model. The ocean\udcirculation is realistic, and property transports are comparable to observations. The Antarctic Circumpolar\udCurrent (ACC) carries 144 Sv (Sv 106 m3 s1) of water eastward across Drake Passage, increasing to 155\udSv south of Australia because of the Indonesian Throughflow (ITF). There is a clear Indo-Pacific gyre\udaround Australia exchanging 10 Sv, 0.9 PW of heat, and 0.2 Sv of freshwater through the ITF, and there\udis a 9-Sv leakage from the Tasman Sea to the Indian Ocean. The transport of heat and freshwater by eddies\udis localized to the upper 1000 m of the water column and specific regions, such as western boundary\udcurrents, confluences, and the subantarctic front (SAF). Eddy transport of heat and freshwater is negligible\udin gyre interiors and south of the SAF but is vital across the northern edge of the ACC, in particular at the\udAgulhas Retroflection where eddies accomplish almost 100% of the net ocean heat and 60% of the\udsouthward freshwater transport. The eddy transport is almost zero across the latitude of Drake Passage\udwhile in a quasi-Lagrangian frame eddy transports are significant across the ACC but surprisingly are still\udsmaller than the mean transport of heat. Mean and eddy property transport divergences are found to be\udstrongly compensating in areas of high eddy activity. This is caused by increased baroclinic instability in\udstrong mean flows, which induces an opposing eddy transport. This relationship is observed to be stronger\udin the case of horizontal heat transport than in corresponding horizontal freshwater transports