noaa-icecore-12887
GISP2 Ice Core 4000 Year Ar-N Isotope Temperature Reconstruction
Kobashi, T.; Kawamura, K.; Severinghaus, J.; Barnola, J.M.; Nakaegawa, T.; Vinther, B.M.; Johnsen, S.J.; Box, J.E.
GISP2 Ice Core 4000 Year Ar-N Isotope Temperature Reconstruction
2012-03-30
NCDC-Paleoclimatology
ONLINE Files
Pending
https://www.ncdc.noaa.gov/paleo/study/12887
Investigator
T.
Kobashi
Investigator
K.
Kawamura
Investigator
J.
Severinghaus
Investigator
J.M.
Barnola
Investigator
T.
Nakaegawa
Investigator
B.M.
Vinther
Investigator
S.J.
Johnsen
Investigator
J.E.
Box
earth science
paleoclimate
climate reconstructions|ice cores
surface temperature,delta 15N excess,null,degree Celsius,null,climate reconstructions|ice cores,null,null,N,null
earth science
paleoclimate
climate reconstructions|ice cores
age,null,null,year Common Era,null,climate reconstructions|ice cores,null,null,N,null
earth science
paleoclimate
climate reconstructions|ice cores
surface temperature,delta 15N excess,one standard deviation,degree Celsius,null,climate reconstructions|ice cores,null,null,N,null
earth science
paleoclimate
ice core
nitrogen isotopes
earth science
paleoclimate
ice core
reconstruction
geoscientificInformation
Air Temperature Reconstruction
Arctic
temperature
-2000 AD
1993 AD
3950 cal yr BP
-43 cal yr BP
Complete
72.6
72.6
-38.5
-38.5
3200
3200
Continent
North America
Greenland
GISP2>LATITUDE 72.6>LONGITUDE -38.5
None
Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site.
English
DOC/NOAA/NESDIS/NCEI
National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
https://www.ncdc.noaa.gov/data-access/paleoclimatology-data
DATA Center Contact
Bruce
Bauer
bruce.a.bauer@noaa.gov
paleo@noaa.gov
303-497-6280
303-497-6513
325 Broadway, E/NE31
Boulder
CO
80305-3328
USA
online
ASCII
Kobashi, T., K. Kawamura, J.P. Severinghaus, J.-M. Barnola,
T. Nakaegawa, B.M. Vinther, S.J. Johnsen, and J.E. Box. 2011.
High variability of Greenland surface temperature over the
past 4000 years estimated from trapped air in an ice core.
Geophys. Res. Lett., 38, L21501, doi:10.1029/2011GL049444.
Greenland recently incurred record high temperatures and ice loss
by melting, adding to concerns that anthropogenic warming is
impacting the Greenland ice sheet and in turn accelerating global
sea-level rise. Yet, it remains imprecisely known for Greenland
how much warming is caused by increasing atmospheric greenhouse
gases versus natural variability. To address this need, we reconstruct
Greenland surface snow temperature variability over the past 4000
years at the GISP2 site (near the Summit of the Greenland ice sheet;
hereafter referred to as Greenland temperature) with a new method
that utilises argon and nitrogen isotopic ratios from occluded air
bubbles. The estimated average Greenland snow temperature over
the past 4000 years was -30.7°C with a standard deviation of 1.0°C
and exhibited a long-term decrease of roughly 1.5°C, which is
consistent with earlier studies. The current decadal average
surface temperature (2001–2010) at the GISP2 site is -29.9°C.
The record indicates that warmer temperatures were the norm
in the earlier part of the past 4000 years, including century-long
intervals nearly 1°C warmer than the present decade (2001-2010).
Therefore, we conclude that the current decadal mean temperature
in Greenland has not exceeded the envelope of natural variability
over the past 4000 years, a period that seems to include part of
the Holocene Thermal Maximum. Notwithstanding this conclusion,
climate models project that if anthropogenic greenhouse gas
emissions continue, the Greenland temperature would exceed
the natural variability of the past 4000 years sometime
before the year 2100.
STUDY NOTES: Greenland summit surface snow temperature for the past 4000 years
reconstructed by a new method that utilises argon and nitrogen
isotopic ratios from occluded air bubbles. Simultaneous,
high-precision analyses of d15N and d40Ar in trapped air from
the GISP2 ice core (Kobashi et al. 2008a) was used for this study.
The method for the temperature reconstruction relies on the fact
that gases in firn (unconsolidated snow) layers fractionate
according to the depth and temperature gradient (DT) at the top
and bottom of the layer (Severinghaus et al., 1998). Information
about past depths and DTs at the time of air bubble trapping
in the ice sheet can be retrieved by measuring d15N and d40Ar
in the occluded air in ice cores. Then, the surface temperature
history can be reconstructed by integrating the DTs over time
(Kobashi et al., 2008b, 2010) with a firn densification/heat
diffusion model (Goujon et al., 2003).
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2-temperature2011.xls
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2-temperature2011.txt
USA/NOAA
DIF
Version 9.8.4
2018-12-11
2018-12-11