Progress of Chinese research in physical oceanography of the Southern Ocean

Oceanographic surveying has been one of the key missions of the Chinese National Antarctic Research Expedition since 1984. Using the field data obtained in these surveys and the results from remote sensing and numerical models, Chinese physical oceanographers have investigated the water masses, fronts and circulation patterns in the Southern Ocean. The results of nearly 30 years of research are summarized in this paper. Most oceanographic observations by Chinese researchers have been con- ducted in Prydz Bay and the adjacent seas. CTD （Conductivity Temperature and Depth） data, collected during the past 20 years, have been applied to study several features of the water masses in this region： The spatial variation of warm summer surface water, the northward extension of shelf water, the flow of ice shelf water from the cavity beneath the Amery Ice Shelf, the upweUing of the Circumpolar Deep Water, and the formation of the Antarctic Bottom Water. The circulation and its dynamic factors have been analyzed with dynamic heights calculated from CTD data as well as by numerical models. The structure and strength of the fronts in the southeast Indian Ocean and the Drake Passage were investigated with underway XBT/XCTD （Expendable Bathythermo- graph/Expendable CTD） and ADCP （Acoustic Doppler Current Profiler） data. Their interaunual variations have been determined and the factors of influence, especially the atmospheric forcing and mesoscale oceanic processes, were studied using remote sens- ing data. The dynamic mechanism of the Antarctic Circumpolar Current （ACC） was analyzed by theoretical models. The transport and pattern of the ACC have been well reproduced by coupled sea ice-ocean models. Additional details of ACC variability were identified based on satellite altimeter data. The response of the ACC to climate change was studied using reanalysis data. Prospects for future research are presented at the end of this paper.