Ice Cores and the WAIS What we’ve learned What we still need to accomplish Eric Steig University...
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Ice Cores and the WAIS What we’ve learned What we still need to accomplish Eric Steig University of Washington
Transcript of Ice Cores and the WAIS What we’ve learned What we still need to accomplish Eric Steig University...
Ice Cores and the WAISWhat we’ve learned
What we still need to accomplish
Eric Steig
University of Washington
Conclusions
It is important that we drill deep ice.
It is important that we drill more than one new intermediate to deep ice core (but fewer than 23) in the WAIS.
It is important where we drill.
Why?Low frequency climate variability is not understood.
Why?
Low frequency climate variability is not understood but is the fundamental to the climate change debate (“does recent warming exceed the range of “natural variability”?).
-->Ice cores provide the best low frequency information we have (need ice cores).
-->To assess climate change (at any frequency) we need to get the spatial patterns right (>>1 core).
-->To get the spatial patterns right we need to get the cross-dating right (it matters where we drill).
Modeled pattern of millennial-scale climate change
Vellinga and Wood, 2002
“Patterns of variability” hypothesis
Deep ice cores
Vellinga and Wood, 2002
Well dated deep ice cores
Byrd
Siple Dome
Byrd and Siple Coherence, Holocene
Steig and Alley, 2002, Annals
Papers since 2002 on the GISP2/WAIS relationship
• Ganopolski and Ramstorff, 2002 - Science• Wunsch, 2003 - Quaternary Science Reviews• Schmittner et al., 2003 - QSR• Huybers, 2003 - QSR• Stocker and Johnson, 2003 - QSR• Chaing, Battisti et al., 2004 - Paleoceanography • Roe and Steig, 2004 - Journal of Climate• Brook et al., in review - QSR
Huybers, 2003, QSR
Coherenceof temperature
Phase oftemperature
Coherence Of CH4
Siple, GISP2 Coherence, Glacial
Byrd vs SDM
White & Brook
Z500 PCs vs. T
US ITASE Cores in West Antarctica
3433
47 22
Accumulation(water equiv cm/year)
RAW xsSO4 (RED) AND ssSO4 (GREEN)CONCENTRATIONS FROM 1800-2002 AD
ConclusionsIt is important that we drill deep ice -- because the dating
quality is not yet good enough. The new WAIS core will offer significantly improved dating precision.
It is important that we drill more than one new intermediate to deep ice core (but fewer than 23) in the WAIS -- because there are clearly spatial differences within WAIS.
It is important where we drill.We will still need deep core east of the divide, in the Amundsen
and/or Weddell drainages to capture the full spatial characteristics of low frequency climate variability.
