A new account of Ross Sea waters: characteristics, volumetrics, and variability

• Other Authors: Orsi, Alejandro H., Stoessel, Achim, North, Gerald, Whitworth, Thomas, III
• Format: Book
• Language: English
• Published: Texas A&M University 2007
• Subjects: Ross Sea; climatology; Antarctic; The Antarctic; Ross Island; Drygalski; Colbeck; Cape Colbeck; Antarc*
• Online Access: http://hdl.handle.net/1969.1/5778

A new high-resolution climatology and volumetric ????-S census (???????? = 0.1????C, ????S = 0.01) is constructed for the Ross Sea. Property maps (potential temperature, salinity, and dissolved oxygen) along 40 depth levels and 21 neutral density (????n) surfaces are analyzed. A major inflow of Antarctic Surface Water (AASW) is observed branching off the westward-flowing coastal current near Cape Colbeck. One portion continues poleward hugging the coast while the other follows the shelf break to the west. The characteristic ??????V?????? shape of the Antarctic Slope Front over the western Ross Sea is indicated by a narrow stream of thickened AASW. The entire AASW layer shoals from east to west. Two major shoreward inflows of Lower Circumpolar Deep Water (LCDW) are inferred. A warm and salty tongue from the Balleny Gyre enters the Drygalski and Joides troughs. A similar tongue is exported from the Ross Gyre and enters the Glomar Challenger Trough. No significant LCDW inflow is observed over the eastern slope of the Ross Sea. The thickest outflows of Shelf Water (SW: ???? ?????? -1.85????C, S > 34.5) and new Antarctic Bottom Water (AABW: ???? > -1.85????C, ????n > 28.27 kg m-3) are found along the Drygalski and Joides troughs. Their saltiest (S > 34.7) components are concentrated in the western Ross Sea, whereas the low-salinity varieties are found throughout the Ross Sea shelf. The most voluminous water mass in the Ross Sea is LCDW. The least abundant is AABW found primarily over the western slope. Modified CDW (MCDW) in the western Ross is inferred to be a mixture of 30% AASW and 70% LCDW; whereas central (eastern) MCDW is 40% (60%) AASW and 60% (40%) LCDW. The same water mass composition is inferred for new AABW in the western and central Ross Sea: 25% SW and 75% MCDW. A 40-year freshening trend is detected at different sites along the coastal transit of AASW from Cape Colbeck to Ross Island. In addition to a freshening, the MCDW and high-salinity SW also reveal a cooling trend. Conversely, a warming and salinification is indicated at the main inflows of LCDW.