Extending the history of atmospheric CHExtending the history of atmospheric CH44
concentrations back to 650 kyr agoconcentrations back to 650 kyr ago
European Geosciences Union European Geosciences Union General Assembly 2005General Assembly 2005
Vienna, Austria, 24 - 29 April 2005Vienna, Austria, 24 - 29 April 2005
R. Spahni1, J. Chappellaz2, G. Hausammann1, L. Loulergue2,T. F. Stocker1, J. Jouzel3
(1) Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland(2) Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE, CNRS-UJF), Grenoble, France
(3) Laboratoire des Sciences du Climat et de l‘Environnement (UMR CEA-CNRS), CE Saclay, Gif-Sur-Yvette, France([email protected])
A. Short introduction
B. Available CH4 records (Vostok, Dome C)
C. New CH4 measurements for MIS 12 to 16 and first interpretations
OutlookOutlook
Reconstructing atmospheric CHReconstructing atmospheric CH44
• ice sample size: ~40g
• melt and refreeze technique for the extraction of the air
• analysis by gas chromatography
• reproducibility of ~10ppbv
-480
-440
-400
-360
D (
ice)
[‰]
0 100,000 200,000 300,000 400,000 500,000 600,000
ED C 2 age [years BP ]
400
500
600
700
Dom
e C
CH
4 [p
pbv]
400
500
600
700
Vos
tok
mat
ched
to E
DC
2 C
H4 [p
pbv]
EPICA Dome C & Vostok ice coresEPICA Dome C & Vostok ice cores
Delmotte et al. (2004)Delmotte et al. (2004)
Petit et al. (1999)Petit et al. (1999)
EPICA Community EPICA Community Members (2004)Members (2004)
-480
-440
-400
-360
D (
ice)
[‰]
0 100,000 200,000 300,000 400,000 500,000 600,000
ED C 2 age [years BP ]
400
500
600
700
Dom
e C
CH
4 [p
pbv]
400
500
600
700
Vos
tok
mat
ched
to E
DC
2 C
H4 [p
pbv]
EPICA Dome C & Vostok ice coresEPICA Dome C & Vostok ice cores
New data!New data!
Climate shiftClimate shift
-460
-440
-420
-400
-380
-360
Dom
e C
D
(ic
e) [‰
]
0 100,000 200,000 300,000 400,000 500,000 600,000
ED C 2 age [years BP ]
400
500
600
700
Dom
e C
& V
osto
k C
H4 [p
pbv]
Climate shiftClimate shift
-460
-440
-420
-400
-380
-360
Dom
e C
D
(ic
e) [‰
]
0 100,000 200,000 300,000 400,000 500,000 600,000
ED C 2 age [years BP ]
400
500
600
700
Dom
e C
& V
osto
k C
H4 [p
pbv]
?
Measured CHMeasured CH44 data data
-440
-420
-400
-380
-360
D (
ice)
[‰]
440,000 480,000 520,000 560,000 600,000 640,000
age [yr BP]
300
400
500
600
700
CH
4 [p
pbv
]
BernG renoble
11 13
12 14 16
15.315.1
15.2
-440
-420
-400
-380
-360
D (
ice)
[‰]
440,000 480,000 520,000 560,000 600,000 640,000
age [yr BP]
300
400
500
600
700
CH
4 [p
pbv
]
11 13
12 14 16
15.315.1
15.2
Missing Termination from MIS 14 to 13Missing Termination from MIS 14 to 13
Last Glacial Period MIS 3Last Glacial Period MIS 3
Huber et al. (submitted 2004)Huber et al. (submitted 2004)
420,000 440,000 460,000 480,000 500,000
ED C 2 age [yr BP ]
400
500
600
700
CH
4 [p
pbv
]
100
80
60
40
20
0
% IR
D
4
3 .6
3.2
2.8
2.4
bent
hic
18 O
[‰]
4 .0
3.0
2.0
1.0
plan
cton
ic
18O
[‰]
- - - N orth A tlantic m arine core 980
- EPIC A D om e C ice core
11 1312
Oppo et al. (1998)Oppo et al. (1998)McManus et al. (1999)McManus et al. (1999)
Millennial Scale VariationsMillennial Scale Variations
Conclusions for MIS 16 to 12Conclusions for MIS 16 to 12
• Consistent with the temperature proxy D, mean CH4 levels were lower during interglacials 15 and 13 than in the consecutive interglacials 11, 9, 7, 5 and 1.
• High correlation to Antarctic temperature on glacial- interglacial time scales
• the climatic transition from MIS 14 to 13 is saw tooth shaped instead of showing a clear termination
Thank you for your attention
• rapid CH4 increases are observed millennial scale variations similar to the Last Glacial Period seem to be a robust feature of our climate system