CALM, AnSlope and MORSea experiments

Moored observations from several previous experiments were used in this study. The mooring CA-1 from the CALM experiment was deployed between January 2008 and January 2011³⁶. Measurements from this mooring were compared to those at RSO-P2 and consist of temperature at 43 m, 298 m and 460 m above bottom, salinity at 43 m and 460 m, and velocity at 476 m above bottom. Moored observations from the AnSlope experiment during 2004⁹ were also used to examine the differences in dense plumes between the RSO-P3 mooring and to investigate the timing of the dense plumes relative to the tides. The temperature and salinity from the sensors 10 m above bottom on the M3 (691 m), M4 (984 m), and M5 (1749 m) moorings were examined. Hydrographic data collected at Cape Adare in 2004 during the AnSlope experiment was also compared to the hydrographic section collected in 2018.

The bottom water properties and flow within the Drygalski Trough were compared to the measurements on the slope using the observations at the Marine Observatory of the Ross Sea (MORSea) mooring G maintained over 10 years near 72.4° S, 173° E in ~ 520 m water depth²². Observations of temperature and velocity from 2004 to 2014 from the bottom-most sensors, which range in depth from 8 to 70 m above bottom, were used along with salinity measured from 2005 through 2008²² (see Supplementary Fig. ^S4).