Due to sparse observational data, previous studies on the Southern Ocean have primarily focused on interannual to long-term trends, with few investigations at seasonal to daily timescales. This study utilizes a one-year comprehensive hydrographic mooring dataset deployed from January 2019 to February 2020 at the outer shelf slope of Vincennes Bay, East Antarctica, to assess the multi-timescale variability of the water column from Lower Circumpolar Deep Water (LCDW) to Antarctic Bottom Water (AABW). At the seasonal scale, the entire water column exhibited warming and salinification during the austral autumn and winter, peaking in early to mid-July, with potential temperature increases of 0.15-0.3℃ (and salinity increases of 0.02-0.1 psu) relative to preceding months. This was followed by sharp fluctuating declines, reaching minima in early to mid-September, with decreases of 0.2-0.6℃ (and salinity drops of 0.01-0.14 psu). These seasonal changes were accompanied by coherent density variations, indicating bulk vertical displacement of the water column rather than isopycnal thermohaline changes. At the daily scale, high-frequency temperature, salinity, and pressure signals all revealed pronounced semi-diurnal (M2) tidal signatures, while pressure records also captured distinct diurnal (K1) signals. The diurnal tide appears to be dominated by a barotropic mode, evident in pressure spectra, whereas the semi-diurnal tide excites strong baroclinic internal tides over the slope, detectable in both thermohaline and pressure records. The flow field was predominantly northwestward, characteristic of slope currents, but exhibited significant seasonal shifts: westward flow dominated from January to June, gradually transitioned to eastward flow from July to September, and then reverted to westward flow thereafter. This study provides key short-term variability constraints for accurately assessing water-column displacement and its response to climate change, by revealing year-round thermohaline evolution, flow regime transitions, and distinct tidal characteristics at the outer continental slope.

暂无