HR: 13:30h
AN: C43B-01    [Abstracts]
TI: Is Lake Vostok Really Sealed?
AU: * Bindschadler, R
EM: Robert.A.Bindschadler@nasa.gov
AF: NASA, Code 614.0 Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Wang, W
EM: weili@icesat2.gsfc.nasa.gov
AF: SGT, Code 614.1 NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AB: The waters of Lake Vostok are both replenished and drained by the ice sheet that is dragged across its surface. We address the question of the larger-scale cycling of water through this system, i.e., how long does it take new snow to enter the lake and how long does it take water removed from the lake to enter the ocean? Employing a numerical ice sheet model that includes anisotropic flow, we find that it takes approximately one million years both to transport surface snow into the lake and an additional one million years to transport accreted lake water to the ocean. We examine a number of flow trajectories. Water frozen from the south side of the lake is routed to the Ross Ice Shelf where it eventually melts off the bottom of the ice shelf. Ice transiting the north side of the lake is routed towards Wilkes Land where calving returns it to the southern Pacific Ocean. Thus most of the accreted ice is delivered to the Ross Ice Shelf and some of it may remain as ice until calved off the front of the ice shelf. Assuming that the lake has been covered by a thick ice sheet for 14 million years and that accretion rates withdraw a volume equal to the lake's volume every 40,000 years (correcting an earlier published estimate with a revised lake volume), even modest circulation leads to the conclusion that most of the original water of the lake has been replaced. There remains the possibility that a connected network of subglacial water channels hinted at by satellite altimetry analysis could provide a much quicker connection from the lake to the ocean.
DE: 1655 Water cycles (1836)
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2005 Joint Assembly