A priori estimates of mixing and circulation in the hard-to-reach water body of Lake Vostok
Lake Vostok in Eastern Antarctica is covered by a ∼4000 m thick ice sheet that glides over the sub-glacial water body on a time scale of ∼20 000 years. As a basis for “pre-expedition” planning, a priori estimates are made for water temperature, heat flux and currents. Whereas vertical temperature gr...
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Language: | English |
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Online Access: | https://doi.org/10.1016/S1463-5003(00)00007-X |
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fteawag:oai:dora:eawag_4083 2023-05-15T14:13:48+02:00 A priori estimates of mixing and circulation in the hard-to-reach water body of Lake Vostok Wüest, Alfred Carmack, Eddy 2000 https://doi.org/10.1016/S1463-5003(00)00007-X eng eng Elsevier Ocean Modelling--Ocean Model.--journals:2250--1463-5003--1463-5011 eawag:4083 journal id: journals:2250 issn: 1463-5003 e-issn: 1463-5011 ut: 000208277500003 local: 7015 scopus: 2-s2.0-0002520871 doi:10.1016/S1463-5003(00)00007-X Text Journal Article 2000 fteawag https://doi.org/10.1016/S1463-5003(00)00007-X 2023-04-09T04:48:23Z Lake Vostok in Eastern Antarctica is covered by a ∼4000 m thick ice sheet that glides over the sub-glacial water body on a time scale of ∼20 000 years. As a basis for “pre-expedition” planning, a priori estimates are made for water temperature, heat flux and currents. Whereas vertical temperature gradients are predicted to be extremely small due to geothermally driven convective turbulence, horizontal temperature gradients are expected to be present due to the horizontal gradient of the pressure-dependent freezing point at the base of the sloped ice ceiling. Except at the lake’s deepest location, where a thin stratified layer may develop, the vertical in situ temperature profile will be near the adiabatic lapse rate. Based on internal heat fluxes associated with observed melting and re-freezing at the base of the ice sheet we calculate internal currents by assuming geostrophic balance. Vertical and horizontal motions are both expected to lie in the range of fractions of mm/s. Ice plasticity (hydrostatic adjustment) and water–ice heat exchanges are predicted to flatten the ice-cover quickly to a remarkably smooth terrain while the ice moves over the lake. These results corroborate well with the recent finding that only the upper part of accreted lake water, retrieved from the Vostok ice-core, contains particles. Our predictions are discussed with respect to uncertainties and the experimental challenges to be met. Article in Journal/Newspaper Antarc* Antarctica ice core Ice Sheet DORA Eawag Lake Vostok ENVELOPE(106.000,106.000,-77.500,-77.500) Ocean Modelling 2 1-2 29 43 |
institution |
Open Polar |
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DORA Eawag |
op_collection_id |
fteawag |
language |
English |
description |
Lake Vostok in Eastern Antarctica is covered by a ∼4000 m thick ice sheet that glides over the sub-glacial water body on a time scale of ∼20 000 years. As a basis for “pre-expedition” planning, a priori estimates are made for water temperature, heat flux and currents. Whereas vertical temperature gradients are predicted to be extremely small due to geothermally driven convective turbulence, horizontal temperature gradients are expected to be present due to the horizontal gradient of the pressure-dependent freezing point at the base of the sloped ice ceiling. Except at the lake’s deepest location, where a thin stratified layer may develop, the vertical in situ temperature profile will be near the adiabatic lapse rate. Based on internal heat fluxes associated with observed melting and re-freezing at the base of the ice sheet we calculate internal currents by assuming geostrophic balance. Vertical and horizontal motions are both expected to lie in the range of fractions of mm/s. Ice plasticity (hydrostatic adjustment) and water–ice heat exchanges are predicted to flatten the ice-cover quickly to a remarkably smooth terrain while the ice moves over the lake. These results corroborate well with the recent finding that only the upper part of accreted lake water, retrieved from the Vostok ice-core, contains particles. Our predictions are discussed with respect to uncertainties and the experimental challenges to be met. |
format |
Article in Journal/Newspaper |
author |
Wüest, Alfred Carmack, Eddy |
spellingShingle |
Wüest, Alfred Carmack, Eddy A priori estimates of mixing and circulation in the hard-to-reach water body of Lake Vostok |
author_facet |
Wüest, Alfred Carmack, Eddy |
author_sort |
Wüest, Alfred |
title |
A priori estimates of mixing and circulation in the hard-to-reach water body of Lake Vostok |
title_short |
A priori estimates of mixing and circulation in the hard-to-reach water body of Lake Vostok |
title_full |
A priori estimates of mixing and circulation in the hard-to-reach water body of Lake Vostok |
title_fullStr |
A priori estimates of mixing and circulation in the hard-to-reach water body of Lake Vostok |
title_full_unstemmed |
A priori estimates of mixing and circulation in the hard-to-reach water body of Lake Vostok |
title_sort |
priori estimates of mixing and circulation in the hard-to-reach water body of lake vostok |
publisher |
Elsevier |
publishDate |
2000 |
url |
https://doi.org/10.1016/S1463-5003(00)00007-X |
long_lat |
ENVELOPE(106.000,106.000,-77.500,-77.500) |
geographic |
Lake Vostok |
geographic_facet |
Lake Vostok |
genre |
Antarc* Antarctica ice core Ice Sheet |
genre_facet |
Antarc* Antarctica ice core Ice Sheet |
op_relation |
Ocean Modelling--Ocean Model.--journals:2250--1463-5003--1463-5011 eawag:4083 journal id: journals:2250 issn: 1463-5003 e-issn: 1463-5011 ut: 000208277500003 local: 7015 scopus: 2-s2.0-0002520871 doi:10.1016/S1463-5003(00)00007-X |
op_doi |
https://doi.org/10.1016/S1463-5003(00)00007-X |
container_title |
Ocean Modelling |
container_volume |
2 |
container_issue |
1-2 |
container_start_page |
29 |
op_container_end_page |
43 |
_version_ |
1766286344279031808 |