Fig. 2: Thermocline depth and meltwater flux, and their causing factors.
a Net modified Circumpolar Deep Water (mCDW) transport (black dotted line) across the boundary (X–X’) in Fig. 1a, 0.5oC isotherm depth (red line) averaged south of X–X′ in Fig. 1a, and meltwater flux (blue line) from Thwaites and Pine Island Glaciers. Magenta and cyan colour bars at the top of the graph indicate high- and low-melt years, respectively (Methods). b The leading mode’s principal component (PC1) of ocean current (black line) (Methods), southward Antarctic Coastal Current (AACC) transport (grey dotted line) across 74.4°S, 104–101.5°W in X–X’ in Fig. 1a, and 0.5 °C isotherm depth (red line) as in a. c The PC1 (black line) as in b, depth-averaged relative vorticity (blue line) averaged south of X–X’ in Fig. 1a, and time-integrated vertical velocity (WB) anomaly in the bottom layer (red line) (Methods). d The PC1 (black line) as in b and time-integrated Ekman pumping velocity (WEk) anomaly with positive values indicating upwelling, derived by ocean surface stress curl (red line) (Methods). Both the time-integrated vertical velocity, denoted as WEk in c and WB in d, were averaged south of A–A’ in Fig. 1a to compare their relative magnitudes. Seasonal variability in all the quantities in a–d is removed by applying a 13-month moving average filter.
