Site Survey Methods in Glacial Ice Drilling
GESEP
EARTH PROBING SCHOOL 2011
Frank.Wilhelms@awi.de Alfred Wegener Ins6tut
für Polar-‐ und Meeresforschung Bremerhaven
EPICA
E U
R O P E A N P R O J E C T F O R I C E C O R I N G I N A N
T A R C T I C
A
D O M E C O
N C O R D I A D R O N Nbottom I N G M A U D L A N D 2774.15 m 17.01.2006 Dronning Maud Land
Polar ice sheets
Snow accumulation Snow accumulation
Iceberg calving
Iceberg calving Ablation
subglacial melting Ocean bedrock
ice shelf Inlandice /
Ice sheet Summit
Equilibrium line
typical for
Antarctica Greenland
Ice thicknees
Ice thickneesMean: 1575 m Max: 3028 m Mean: 2034 m Max: 4775 m
500 - 1000 km ca. 2000 km 100 - 600 km
HansOerter, 2001 with modifications Subglacial Lake
Snow accumulation Snow accumulation
Iceberg calving
Iceberg calving Ablation
subglacial melting Ocean bedrock
ice shelf Inlandice /
Ice sheet Summit
Equilibrium line
typical for
Antarctica Greenland
Ice thicknees
Ice thickneesMean: 1575 m Max: 3028 m Mean: 2034 m Max: 4775 m
500 - 1000 km ca. 2000 km 100 - 600 km
Hans Oerter, 2001 with modifications Subglacial Lake
1 mm 150 m
300 m
entrapped air bubbles
in the ice
the entrapment of air in the firn
10 m 40 m
70 m
100 m
1 cm
x-‐ray-‐
computer-‐
tomography
Freitag, Wilhelms,
Kipfstuhl, JGlaciol, 2004
Ice Cores are an archive of the past atmosphere
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Lüthi et al., Nature, 2008 Loulerge et al., Nature, 2008
Major sources of information on past ocean and atmosphere
MARINE SEDIMENT CORES
ICECORES
Temperature archive: The isotope thermometer
summer winter
Fractionation of water isotopes during phase changes
after Stauffer, 2001
Willi Dansgaard, The O18-abundance in fresh water, Geochim. et Cosmochim. Acta 6, 1954
Ice sheets’ sibling: The ocean The glacial effect
source: wikipedia
Shackleton, N. Oxygen Isotope Analyses and Pleistocene
Temperatures Re-assessed, Nature, 215, 15-17, 1967
EPICA-MIS: synchronization of ice
and marine sediment records
Dansgaard, Johnsen, Møller, Langway, Science, 1969
Da6ng of ice cores
€
dw
dy = − rh ; h ≤ y ≤ H dw
dy = − rz ; 0 ≤ y ≤ h
Dansgaard-‐Johnsen model: ver6cal speed w:
H
h
solving the Dansgaard-‐Johnsen model
• integra6on of with constant rate thinning rate r
• yields for w:
• and constant accumula6on at surface w(H)=-‐A yields
• 6me is the integral of inverse speed by height above bedrock
€
w( y) = − r
2 y
2; 0 ≤ y ≤ h w( y) = − rh
2 (2 y − h ) ; h ≤ y ≤ H
€
dw
dy = − rh ; h ≤ y ≤ H dw
dy = − rz ; 0 ≤ y ≤ h
€
t( y ) = 1
w dy
H y
∫
Dansgaard-‐Johnson: depth-‐6me rela6on
• just solving the integral yields
• logarithmic age-‐depth rela6on within h above bed and an
• inverse age-‐depth rela6on above h
• influenced by: accumula6on, ice thickness, flow
€
t( y ) = 2 H − h
2 A ln 2 H − h
2 y − h ; 0 ≤ y ≤ h t(y) = 2H - h
2A ln 2 H − h
h + 2 H − h A
h
y − 1
⎛
⎝ ⎜ ⎞
⎠ ⎟ ; h ≤ y ≤ H
The depth scale in the data sets
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EPICA Community Members, Nature 2004
800
600
400
200
0
age / kyr B.P.
3000 2500
2000 1500
1000 500
0
depth / m
El Chichon? 10Be/14C 10Be/14C YD/Holocene PB/BO 10Be peak Mt Berlin erupt. term. II air content air content air content air content air content air content air content air content air content air content 18Oatm 18Oatm B-M reversal
Krakatua Tambora Huaynaputina
Kuwae El Chichon? UnidentifiedUnknown 10Be/14C PB/BO 10Be peak
age-depth relation model age tie points top correction
bottom correction (18Oatm Vostok )
EDC3 age-‐depth rela6on
-‐10 -‐8 -‐6 -‐4 -‐2 0 2 4
EPICA Dome C proxy temperature / °C rela6ve to present
1600000 1200000
800000 400000
0
age / years B.P. (= 1950)
5.0 4.5 4.0 3.5 3.0
benthic δ 18 O / ‰ proxy for ice volume
What to expect even earlier?
40 kyr world 100 kyr world
Jouzel et al. (2007) Lisiecki & Raymo (2005)
The scientific goals - IPICS
1. The oldest ice core: A 1.5 million year record of climate and greenhouse gases from Antarctica (a time period where Earth’s climate shifted from 40,000 year to 100,000 year cycles).
2. The last interglacial and beyond: A northwest Greenland deep ice core drilling project (a deep ice core in Greenland recovering an intact record of the last interglacial period).
3. The IPICS 40,000 year network: A bipolar record of climate forcing and response.
5. The IPICS 2k Array: A network of ice core climate and climate forcing records for the last two millennia
A fifth, and critical, element of IPICS is the development of advanced ice core drilling technology. A technical white paper, entitled "Ice Core Drilling Technical Challenges" addresses this.
www.pages.unibe.ch/science/initiatives/ipics Non exclusive list, more will follow if promoted by science, e.g. biodiversity in ice cores, sub-glacial lakes, ice dynamics, etc.
IPICS: The IPICS 40,000 year network:
a bipolar record of climate forcing and response
Willi Dansgaard memoirs: Frozen Annals hkp://
www.iceandclimate.nbi.ku.dk/publica6ons/
frozen_annals/
The Greenland story
GRIP
GRIP – GISP2
Grootes et al., Nature 366, 1993
ice
thickness
hkp://nsidc.org/data/atlas/atlas_info.html Bamber et al., JGR, 2001
Accumu-‐
la6on
hkp://nsidc.org/data/atlas/atlas_info.html Bales et al., JGR, 2009
bedrock topography
hkp://nsidc.org/data/atlas/atlas_info.html Bamber et al., JGR, 2001
bedrock undula6ons
at 20 x ice thickness
Layberry & Bamber, JGR, 2001
Bamber et al., JGR, 2001
Data resolu6on -‐ flight lines
Nixdorf & Göktas, J. Appl. Geophys., 2001
Results of local studies
Nixdorf & Göktas, J. Appl. Geophys., 2001
volcanic horizons
15 cm
810 m depth (EDML)
(approx. 20 kyr BP)
Foto: Sepp Kipfstuhl
mapping the ice thickness and internal reflec6ons
Steinhage et.al., Journal of Applied Geophysics 47 (3-‐4), pp. 183-‐189, 2001
POLAR 2 (D-‐CAWI)
Deep ice cores in Antarc6ca and Greenland
Antarc6c Digital Database, Ekholm, 1998, maps by Steinhage with modifica6ons
Internal horizons at ice core drill sites
Internal horizons at ice core drill sites
Internal horizons at ice core drill sites
FDTD synthe6c radar traces to link ice-‐core and radar surveys
T raveltime (µs )
S 2 : GA P ice =3.09
S 4 : GA P ice =3.09 S 3 : DE P ice =3.09
S ‘3 : DE P ice =3.20
S ‘5 ice =3.20
2 3 4 5 10 15 20 25
S 1 : DE P ice =3.09
R 1 : 023150
R 2 : 033042
Eisen et.al., 2006
Linking Ice Cores and surveys in East
Antarc6ca
map: Daniel Steinhage
Data: Antarc6c Digital Database
We have the tools, but to bring the fuel is the challenge
Siegert et.al.,
Antarc=c Science 17 (3), 453–460, 2005
NorthGRIP – a warning
Dahl-‐Jensen et al., JGlaciol, 1997 NGRIP community members, Nature, 2004
Only really con6nuous radar layers may be used for
tracing from one loca6on to another!
NGRIP -‐ mel6ng at the bokom
hkp://geophysics.ou.edu/geomechanics/
notes/heaplow/global_heat_flow.htm Pollack et al., RG, 1993
Geothermal heat flux from model interpola6on
Greve, Ann. Galciol., 42, 2005
crustal thickness from seismology an
isosta6c analysis
Braun et al., EPSL, 2007NGRIP – anyhow good science
NGRIP community members, Nature, 2004
Linking of Hemispheres
EPICA community members, Nature 2006 EPICA DML, NGRIP
-‐52
-‐48
-‐44
T s u r f [ ° C ]
-‐450
-‐430
-‐410
A C R E D C
δ D c o r r [ ° / ° ° ]
-‐52
-‐49
-‐46
-‐43
E D ML
δ 1 8 O c o r r [ ° / ° ° ]
A I M 8 A I M 1 2
A I M 1
A I M 2
A I M 4 5 6 7
3 9 1 0 1 1
4 . 1
-‐40
-‐37
-‐34
A 1 A 2 B y r d
δ 1 8 O [ ° / ° ° ]
N o r t h G R I P
D O 1
2 3 4 5 6 7 D O 8
9 1 0 1 1 D O 1 2
-‐45 -‐41 -‐37 -‐33
4 . 1
H 1
H 2 H 3 H 4 H 5
r e n a d H
G e l n C
350 500 650 800
10000 20000 30000 40000 50000 60000
NGRIP age / years BP (1950)
4
c o m p o s i t e
E D M L
CH 4 / ppbv δ 18O / ‰
EDML-‐ Ice Coring goes arts
Siegert et.al.,
Antarc=c Science 17 (3), 453–460, 2005
NEEM
• N 77°26‘54.93‘‘,
• W 51°03‘19.89‘‘
• Al6tude: 2484 m a.s.l.
• Ice Thickness: 2542 m
Is there an Eemian?
Susanne Liljia Buchardt, PhD thesis, Ice and Climate Centre, Univ. København, 2009
Radar reflectors from NGRIP to NEEM
Susanne Liljia Buchardt, PhD thesis, Ice and Climate Centre, Univ.
København, 2009
Age
(kyr) Depth
(m) z (m)
1.4 273 2644
2.7 501 2416
3.2 571 2346
4.0 689 2229
4.8 802 2116
5.9 955 1963
7.5 1146 1771 10.2 1396 1521 14.6 1600 1318 37.7 2055 863 45.0 2182 735 51.0 2284 633 74.6 2553 365 Age depth at NGRIP and eleva6on above sea level at NGRIP (Table 2.2)
The European Project for Ice Coring in Antarc6ca
Antarc6c Digital Database, Ekholm, 1998, map by Steinhage with modifica6ons
Dome C
Vostok
South Pole
Casey
Dumont d’Urville
Mario ZucchelliMcMurdo
Syowa
Halley
Neumayer
Kohnen
Dome Fuji
Davis
Mirny
Molodezhnaya
Zhongshan
Byrd
EDC EDML
DF Byrd V
Explore the area
• GPS measurements for ground truthing, ice flow and digital eleva6on model
• shallow ice cores, snow pits and automa6c weather sta6ons for proxy establishment
• radar survey for ice thickness determina6on
• geophysical survey to study underlying crust
isotope thermometer for EDML
Graf, W., Oerter, H., Reinwarth, O., S6chler, W., Wilhelms, F., Miller, H., Mulvaney, R. Stable-‐isotope records from Dronning Maud Land, Antarc=ca, Annals of Glaciology, 35, 195–201, 2002.
Antark6s (Dronning Maud Land) T =
1.3°C /‰ * δ
18O + 14.8°C
-48 -44 -40 -36
!18 O / ‰
2.0 1.5
1.0 0.5
0.0
depth (firn) / m
seasonal varia6ons
snow pit 0203 in the EDML vicinity
Oerter et al., Annals of Glaciology, 2004.
C. H. Reijmer et al., JGR, 2006: hkp://www.phys.uu.nl/~wwwimau/research/ice_climate/aws/
antarc6ca_sta6ons.html#aws9
T = 1.3°C /‰ * δ18O + 14.8°C -‐52 °C
-‐32 °C
Hans Oerter
explore the area for logis6c access
Accumula6on rate folio for modelling of the East Antarc6c ice sheet
Huybrecht et al., AnnGlaciol 30, 2000
ice sheet models
Huybrechts, Glacier Science and Environmental change, ed. P. Knight, Blackwell, 2006
ice sheet models to improve the interpreta6on of the ice cores
Huybrechts, Clim. Past, 2007
ice sheet models to search oldest ice
Huybrechts, as reproduced in Nature, 2007
BEDMAP
hkp://www.antarc6ca.ac.uk/Resources/AEDC/bedmap/examples/bed10.gif
Mapping of the ice sheet – BEDMAP dataset
hkp://www.antarc6ca.ac.uk/Resources/AEDC/bedmap/database/bedmap_coverage.html
Linking Ice Cores and surveys in East
Antarc6ca
map: Daniel Steinhage
Data: Antarc6c Digital Database
We have the tools, but to bring the fuel is the challenge
Siegert et.al.,
Antarc=c Science 17 (3), 453–460, 2005
Logis6cs for 40k projects
Twin Oker DHC-‐6, Basler BT-‐67 based logis6cs, with ship supply to the coast, personnel
moved through major air links. Approved by Berkner Island, Talos Dome, James Ross
Island
Opera6on in Antarc6ca – heavy equipment
European logis6c means
surface traverses Air drop capability by
ALCI
US logis6c means addi6onally LC-‐130 heavy aircra}
opera6on on the ice
Lightweight
field camps
Personnel to and from Antarc6ca
© 2002 Seth White
DROMLAN AIR NETWORK
Troll Novo Airbase
