It is created mainly due to the high surface winds blowing off the Antarctic continent which helps cool and oxygenate it.
The northern limit of the core of Weddell Sea Bottom Water lies against the southern edge of the Scotia Ridge, suggesting that the circulation and property distributions are strongly influenced by bathymetry.
This range also represents the coldest bottom water observed at the base of the continental slope in the northwestern corner of the Weddell Sea.
[2] It is proposed that the more saline, lower-oxygen WSBW is derived from shelf water descending into the deep ocean in the southwest Weddell Sea.
Fahrbach et al. propose that low-salinity bottom water is formed near the Larsen Ice Shelf.
[2][3] McKee et al., conducted a study of the variability of bottom water temperature relative to El Niño-Southern Oscillation (ENSO), Southern Annular Mode (SAM), and Antarctic Dipole (ADP).
Warm ENSO events cause the increase of sea ice advection and more coastal polynyas which allows for more dense shelf water availability.
Their research suggests that there needs to be large ENSO and SAM events in order for the anomalies in WSBW temperature can be noticed.
With a strong ENSO event, sea ice is greatly reduced during the summer which exposes more surface water to the wind allowing it sink.
If the ENSO even is weak enough, the surface winds off the Antarctic coast can shift direction which creates a reduction in shelf water.