Fig. 1: Not-so-dense shelf water and its outflow from the Dibble Polynya.
From: Emerging outflow of not-so-dense shelf water from an East Antarctic polynya
a Annual sea ice production (m year−1) along the East Antarctic coast. Major coastal polynyas are labelled. b Annual mean bottom temperature (°C) and the extent of DSW defined as annual mean σθ of 27.79 kg m−3 for water colder than −1.5 °C (green contour; see Methods for the rationale of using potential density), derived from the Southern Ocean Monthly Climatology21. White arrows depict generalised pathways of Cape Darnley Bottom Water (CDBW), Adélie Land Bottom Water (ALBW), and Ross Sea Bottom Water (RSBW). Not-so-dense shelf water is found near the Shackleton, Vincennes, and Dibble Polynyas. c The Dibble Polynya region. Black rectangle delineates the “area of interest” for hydrographic sampling. Coloured markers represent station locations, with colours corresponding to the legend in (d). In (a)–(c), ice shelves and landfast sea ice62 and the 1000, 2000, and 3000 m isobaths (white contours)63 are shown. d Neutral density–dissolved oxygen (µmol kg−1) plot for hydrographic data collected within the area of interest. Data points are coloured according to the survey year and cruise identifier: 2024 (IN2024V01, blue), 2019 (KY1804, orange), 2018 (IN2018V01, green), 1996 (AR9604, red), 2015 (NBP1503, purple), 1980s (Soviet Union, brown), 1960s-70s (Eltanin, pink), and 1950s (Soviet Union, dark grey). Lines connect sequential profiles of bottle data. Light grey markers are the CCHDO (CLIVAR and Carbon Hydrographic Data Office) data from the ALBW source region with bottom depth deeper than 1500 m, presenting oxygenated water generally denser than 28.30 kg m−3.
