Ice - Water interactions in the
subglacial Lake Vostok, Antarctica:
numerical simulations

(1)Kommission für Glaziologie
Bayrische Akademie
der Wissenschaften


Christoph Mayer1, Klaus Grosfeld2, Malte Thoma1,2
(2)Alfred-Wegener-Institut für
Polar- und Meeresforschung

Klimawissenschaften

Projekt im Rahmen des DFG-Schwerpunktprogramms 1158
"Antarktisforschung mit vergleichenden Untersuchungen in arktischen Gebieten"

Outline:

The investigation of subglacial Antarctic lakes like Lake Vostok is a central goal of the SCAR-SALE initiative during International Polar Year (IPY). Within this program paleo-climate record analyses, technological advances in subglacial lake access, and investigations on hydrological/limnological conditions in subglacial environments are gathered. Our project contributes with modelling efforts to these topics and yields estimates of probable lake conditions and sensitivities of the environment to changes in their setting and composition.

click to download high resolution image
Subglacial Lakes in Antarctica

click to download high resolution image
Lake Vostok cartoon by M. Studinger
Since the final discovery of the subglacial Lake Vostok in the centre of East Antarctica strong efforts have been made to investigate this extremely inaccessible water body. Direct access to the lake is difficult, but new techniques could serve as a forerunner for penetrating the Jovian moon Europa's ice cover. Recovering microbes from refrozen lake water in the Vostok ice core additionally boosted research efforts in connection with Lake Vostok. During the last few years a wealth of information about the physiography and the physical conditions of the lake has been gathered. Former numerical model results concerning the dynamic conditions in the lake are now out-dated by new ideas about the lake geometry and the water composition. Also additional processes like the influence of tides need to be taken into account for simulating more realistic lake conditions which, in turn, could explain mass exchange, ice formation, release of biogenic material and identify regions of different dynamic activity. Such information is essential for deciding where to penetrate the ice cover, install sensors and retrieve water and sediment samples. This project aims at further develop an already existing model, include new physical processes and adapt it to the new lake geometry and water conditions. With this model the current conditions in the lake as well as sensitivity scenarios for different water compositions, thermal boundary conditions and the ice sheet evolution will be investigated. The results will allow an entirely new assessment of lake conditions, lake stability and evolution.


Major Goals of the Project:

This project aimes to numerically simulate the dynamics and exchange processes within Lake Vostok. Influences of different boundary conditions (e.g., geothermal heat flux, salinity content, ice sheet load) on the system as well as their feedbacks will be investigated. The central task to perform this is the adaptation of a numerical 3-dimensional ocean general circulation model on subglacial lake conditions. The model is a revised version of an ocean general circulation model that has been used for earlier studies on Lake Vostok. Various combinations of eddy viscosity and diffusivity, as well as Prandtl Numbers are applied to gather parameters suitable to model flow in such an extreme environment.

Detailed experiments for the most recent bathymetric and ice thickness data set are peformed to investigate the flow regime and the mass exchange with the overlying ice sheet. Virtual particles injected in limited areas of the Lake will show the propagation of tracers within the lake, indicating the flow and probable trace element exchange within the Lake.

This project will therefore contribute to a better understanding of subglacial lake dynamics and will improve our knowledge about the sensitivity of such an extreme environment at the base of the Antarctic ice sheet.


(a) (b)
Comparison of (a) old (Mayer et al., 2003) and (b) new (Studinger et al., 2005)
Lake bathymetry used for modelling the circulation in Lake Vostok.



Publications


Presentations:

Mayer, C., K. Grosfeld, J. Lieser, 2006:
Ice-water interaction in the subglacial Lake Vostok: numerical simulations
Poster presentation DFG-Begutachtung, Schwerpunktprogramm 1158
Lieser, J., K. Grosfeld, Mayer, C., 2006:
Internal circulation of Lake Vostok: a model study based on new geophysical data
Poster presentation SALE on the IPY workshop, 24.-26.4.2006, Grenoble, France
Mayer, C., M. Thoma, K. Grosfeld, 2007:
Ice-water interaction in the subglacial Lake Vostok: numerical simulations
Poster presentation DFG-Report-Colloquium, 12.-14.2.2007, AWI, Bremerhaven
Visit our Poster:
Thursday 19 April 2007
Hall A, 15:30-17:00
Thoma, M., K. Grosfeld, C. Mayer, M. Studinger 2007:
Subglacial Lake Vostok, Antarctica: a model study based on new geophysical data
Poster presentation European Geosciences Union, General Assembly,
Vienna, Austria, 15-20 April 2007, SRef-ID: 1607-7962/gra/EGU2007-A-03698.
Talk at ISAES:
Monday 27 August 2007
Thoma, M., K. Grosfeld, C. Mayer 2007:
Modelling tracer dispersion in subglacial Lake Vostok, Antarctica
The 10th International Symposium on Antarctic Earth Sciences (ISAES),
Univ. of California, Santa Barbara, USA, 26-31 August 2007


Project Funding:

Organisation:

Contract Number:
Period:
Deutsche Forschungsgemeinschaft (DFG)
Priority Programm 1158, Abstract
MA3347/1-2
01.01.2006 - 30.11.2008


Staff:

Dr. Chr. Mayer (PI)
Dr. K. Grosfeld (Co-PI)
Dr. M. Thoma
Dr. J. Lieser
(BAdW-KfG)
(AWI)
(BAdW-KfG, AWI)
(former staff: 01/2006-04/2006)
Christoph.Mayer@lrz.badw-muenchen.de
Klaus.Grosfeld@awi.de
Malte.Thoma@awi.de
now: Jan.Lieser@acecrc.org.au

Links:

Lake Vostok, Antarktis, ein Projekt im Internationalen Polarjahr 2007/2008 (SALE-UNITED)
Institut für Planetare Geodäsie, Erforschung subglazialer Seen unter der antarktischen Eiskappe
Michael Studinger's Homepage on Subglacial Lakes and Lake Vostok

Scientific Committee on Antarctic Research (SCAR) Subglacial Antarctic Lake Environments
Subglacial Antarctic Lake Exploration (SALE) Program Office
Subglacial Antarctic Lake Exploration (SALE) Initiative

Das Internationale Polarjahr 2007/2008
International Polar Year 2007/2008


Author: Klaus Grosfeld
Last update: 01.09.2007