Fig. 1. The west Antarctic Peninsula (wAP) continental shelf. The gray lines indicate 500- and 1000-m isobath, and the permanent ice-shelf cover is indicated by light blue. Also shown are the A, B, and C CTD lines visited during the fall and winter survey cruises of 2001, the high-resolution Section I, the locations of the 2001 A1 and A2 Moorings and of the British Antarctic Survey Rothera Station.

Fig. 2. Schematic of the A1 mooring, deployed during 2001 and early 2002 off Adelaide Island. One of the VACMs had a temperature recorder (VACM/T) and the other a pressure recorder (VACM/P). The dashed line shows a profile of the cross-shelf bathymetry southwest of the mooring site.

Fig. 3. Evolution of the hydrographic structure on the mid-shelf of the wAP (A2 mooring site). The left panel shows a θ–S diagram of profiles taken throughout 2001 and 2002. The gray boxes illustrate the typical range of the Antarctic Surface Water (AASW), Winter Water (WW), and Circumpolar Deep Water (CDW). The dashed line indicates the freezing point of sea-water. The right panels show the corresponding potential temperature (θ), salinity, and potential density (σ_θ) profiles.

Fig. 4. Sea-surface salinity (SSS) and sea-surface temperature (SST) for the fall (CTD and underway data, top panels) and winter (CTD data, bottom panels) of 2001, collected during the SO GLOBEC broad-scale cruises on board the RV/IB N.B. Palmer.

Fig. 5. Potential temperature–salinity (θ–S) diagrams from line A (top panels), B (middle panels) and C (bottom panels) for the fall of 2001 (left column) and winter of 2001 (right column). The solid black lines are stations from the mid- and outer shelf, and the dashed red lines are nearshore stations. The dashed line in each panel indicates the freezing point of sea-water. Station locations are plotted in Fig. 1.

Fig. 6. Gridded temperature, salinity, and along-shelf velocity (ADCP) data from cross-shelf Section I, occupied on June 1, 2001. The red dots indicate the approximate location of BIOMAPER-II dives (top and middle panels) and the ADCP 5-min averages (bottom panel). The thick black line in the middle panel indicate the 34.4 isohaline. The dashed black line in the bottom panel indicates the approximate cross-shelf position of the A1 mooring. The along-shelf velocity is defined as the component perpendicular to the section shown in Fig. 1, with negatives values denoting flow to the southwest.

Fig. 7. Mean ADCP velocity profile for the velocity front depicted in Fig. 6 (solid) and mean velocity calculated from thermal wind shear (with an arbitrary offset) over the same cross-shelf region (4–32 km from the coast).

Fig. 8. Cross-shore ADCP sections collected during the fall 2001 SO GLOBEC Cruise. The lines indicate the location of Section I, and sections conducted off the southern coast of Adelaide Island (II), and off the northern (III) and western (IV) coast of Alexander Island.

Fig. 9. Along-shelf velocity ADCP sections, with negative values indicating flow with the coast to the left. The locations of Sections II (top panel), III (middle panel), and IV (bottom panel) are shown in Fig. 8. The thin solid lines near the topography delineate the boundary for the velocity estimates.

Fig. 10. Schematic of the relevant scales of a coastal buoyant plume. The plume front, of width W_s, separates the shelf water of density ρ_o from the lighter (by Δρ) nearshore water. The front depth is h and the front touches the bottom at h_p and a distance from the coast W_b (modified from Lentz and Largier, 2006).

Fig. 11. Time series of along-shelf (positive northeastwards) velocity at the A1 mooring (, ). The colored lines show velocity at different depths from the upward-looking ADCP (65–165 m) and VACMs (309 and 459 m). The shaded areas indicate periods when the fall and winter broad-scale cruises were conducted. The black line shows the sea-ice concentration (in percent) for the nearest grid point to the A1 mooring site from the Special Sensor Microwave/Imager (SSM/I) Satellite data (Comiso, 1999). The magenta line shows the sea-ice draft (in meters) measured with the IPS at the A2 mooring.

Fig. 12. Average of along-shelf velocities from the A1 mooring records for the fall (February–June), winter (here defined as the ice-covered season, from July to October) and spring/summer (from November to the end of the deployment, in February) shown in Fig. 11. The lines indicate the mean values for the season, and the shading the standard error.

Fig. 13. Modeled precipitation minus evaporation (P-E) map for the wAP region (data from van Lipzig et al., 2004). The thick gray line indicates the location of the spine of the peninsula (from the RACMO14 topography), and the height of the topography along the spine is plotted on the left panel. The dashed black line indicates the region upstream of Section I used to compute the freshwater budget.

Fig. 14. Schematic of the path of the APCC. The solid lines indicate sections along the coast where the velocity front and a cross-shelf density gradient was observed. The dashed lines are suggested paths, not derived from observations.

Summary of the cruise dates and number of CTD stations conducted (top), and of the dates, location and local depth of the moorings deployment (bottom)