Jean Robert Petit

Laboratoire de Glaciologie et de Géophysique de l’Environnement (LGGE)

Centre National de la Recherche Scientifique (CNRS)University J. Fourrier 38402 St Martin d’Hères cedex , France

San Petersburg 2013

RAE 35 : Some notes from the 1993-4 field season at Vostok station

19841984

1991

1992-3 field season

1991-2

1992-3

1993-4

5G bore hole

Koudriashov et al.

Chronology of events

Winter 1991 : (Kracilev A. ) - 5G drilling thermal drill.

-1991-2 : 5G got stuck at 2503 m depth

- Drilling fluid density deficit leads to probable hole closure- Project for setting a casing and for the use CFC 141b

-Winter 1992 (Moussiev B.)- Hole deviation at 2200 m depth : 5G1

-1992-3 : Setting geophysical winch and labs

-Winter 1993 (Tchistiakov V. K.)- Drilling 5G1 down to 2755 m depth

-1993-4 : Setting the casing and attempt to rise drilling fluid to the top. - Fluid penetrated into the ice and come back. - ?

2m

42 m

100 m

120m

160m

Vostok 5G hole1993-4 field season

1 2 3 4 5

230m

6

6 bars air pressure

90m

6 7 8 9

Notes from the 1993-4 field season -when filling hole, fluid level cannot be set above 42m

depth -when an air pressure is applied, fluid level went well

below casing end and close off depth of the ice (>130m) When pressure is removed, fluid come back into the

hole Conclusion :

• no leak through the casing

• fluid level cannot be risen

• fluid penetrated into the ice through the ice wall and can come back

• Possible hydro fracturing in the brittle zone

Thank you!

L. Arnaud1, G.Picard1,V. Lipenkov2, E. Lefebvre1, J.R. Petit1

1-LGGE, CNRS- University J Fourrier, St Martin d’Hères Cedex, France2- AARI, St Petersbourg, Russia

San Petersburg 2013

Snow temperature recorders (TAUTO) : preliminary data and comparison with ERA

-Improve knowledge of densification processes (one amongst ideas of J.M. Barnola)

-heat, water vapour transfers, firn ageing(diffusion properties, density, stable isotope…)

Provide « field truth » or constraints for remote sensing measurements (microwaves domain)

Compare with Réanalysis (ERA)

-Set up of temperature grapesDome C (since ~ 2008..)Vostok (since Jan. 2010): 27000 hoursS2 (since Jan. 2011)

Scientific background

Depth (cm)

0

5

10

15

20

30

40

50

60

80

100

140

200

500

1000

Data collection from flash memory to computer (RAE 56, RAE 57)

Winter game:

Remove the frost…

Daily variation

Winter warming waves

summerr

Warm events(8 day gaussian filter)

Vostok 2012

Vostok 2012

2010 2011 2012

Vostok record

Thank you!