Southern jets of the antarctic circumpolar current in the Eastern Pacific Antarctic

The advent of the era of satellite observations of the ocean surface has resulted in a considerable complication of views on the structure of currents in the World Ocean. Up to eight jets came to be distinguished in the zone of the Antarctic Circumpolar Current (ACC). To identify these jets, it is conventional to use qualitative criteria relating a jet’s position to the isoline of a characteristic (temperature, for instance) on any near-horizantal surface. In the present work, based on data of sections and climatology of the World Ocean Circulation Experiment (WOCE) program, we examine the temperature patterns of the subsurface waters of the Southern Ocean, which are commonly used for recognition of fronts. The focus is on the southern jets of the ACC in the Eastern Pacific Antarctic. There are two groups of criteria for these jets, which imply that position of the latter is determined from a certain isotherm on the surface of the minimum (maximum) potential temperature of the Winter water (Upper Circumpolar Deep Water). However, the results of our analysis show that, in fact, the WOCE climatology data allow one to formulate temperature criteria only for the second of the above groups and only for individual sectors of the Southern Ocean-specifically, for the study area. These criteria serve as the basis for determining localization of the southern jets of the ACC in the WOCE sections in this ocean’s region. We also show that the temperature increased by about 0.1°C from the mid-1990s to the mid-2000s in the layer of maximum temperature of the Upper Circumpolar Deep Water in the zone of southern jets of the ACC.