The Cryosphere The “tipping ” temperature within Subglacial Lake Ellsworth, West

Abstract

Abstract. We present results from new geophysical data al-lowing modelling of the water flow within Subglacial Lake Ellsworth (SLE), West Antarctica. Our simulations indicate that this lake has a novel temperature distribution due to sig-nificantly thinner ice than other surveyed subglacial lakes. The critical pressure boundary (tipping depth), established from the semi-empirical Equation of State, defines whether the lake’s flow regime is convective or stratified. It passes through SLE and separates different temperature (and flow) regimes on either side of the lake. Our results have implications for the location of proposed access holes into SLE, the choice of which will depend on scientific or operational priorities. If an understanding of subglacial lake water properties and dynamics is the priority, holes are required in a basal freezing area at the North end o