noaa-recon-12355
Northern Hemisphere Extratropical 1000 Year Temperature Reconstruction
Christiansen, B.; Ljungqvist, F.C.
Northern Hemisphere Extratropical 1000 Year Temperature Reconstruction
2011-12-21
NCDC-Paleoclimatology
ONLINE Files
Pending
https://www.ncdc.noaa.gov/paleo/study/12355
Investigator
B.
Christiansen
Investigator
F.C.
Ljungqvist
earth science
paleoclimate
climate reconstructions
temperature,multiple proxies,null,degree Celsius,null,climate reconstructions,anomalized,regression analysis,N,simple linear regression
earth science
paleoclimate
climate reconstructions
temperature,multiple proxies,null,degree Celsius,null,climate reconstructions,anomalized,null,N,Thin blue curves in Figs. 9 and 14 (upper panel)
earth science
paleoclimate
climate reconstructions
temperature,multiple proxies,null,degree Celsius,null,climate reconstructions,anomalized|smoothed,null,N,Thick red curve in Fig. 14 (upper panel) 50 year smoothed plus bias
earth science
paleoclimate
climate reconstructions
temperature,multiple proxies,percentile,degree Celsius,null,climate reconstructions,anomalized|smoothed,null,N,97.5th percentile; Dashed red curve in Fig. 14 (upper panel); 50 year smoothed
earth science
paleoclimate
climate reconstructions
temperature,multiple proxies,null,degree Celsius,null,climate reconstructions,anomalized|smoothed,null,N,Thick blue curves in Figs. 9 and 14 (upper panel); 50 year smooth
earth science
paleoclimate
climate reconstructions
age,null,null,year Common Era,null,climate reconstructions,null,null,N,null
earth science
paleoclimate
climate reconstructions
temperature,multiple proxies,percentile,degree Celsius,null,climate reconstructions,anomalized|smoothed,null,N,2.5th percentile; Dashed red curve in Fig. 14 (upper panel) 50 year smoothed
earth science
paleoclimate
reconstructions
air temperature
geoscientificInformation
Air Temperature Reconstruction
temperature
1000 AD
2000 AD
950 cal yr BP
-50 cal yr BP
Complete
30
90
-180
180
Geographic Region
Northern Hemisphere
Northern Hemisphere Extratropics>LATITUDE >LONGITUDE
None
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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
Christiansen, B. and F.C. Ljungqvist. 2011.
Reconstruction of the Extratropical NH Mean Temperature over the Last
Millennium with a Method that Preserves Low-Frequency Variability.
Journal of Climate, Vol. 24, Issue 23, pp. 6013-6034, December 2011.
doi: http://dx.doi.org/10.1175/2011JCLI4145.1
A new multiproxy reconstruction of the Northern Hemisphere
extratropical mean temperature over the last millennium
is presented. The reconstruction is performed with a novel
method designed to avoid the underestimation of low-frequency
variability that has been a general problem for regression-based
reconstruction methods. The disadvantage of this method is an
exaggerated high-frequency variability. The reconstruction
is based on a set of 40 proxies of annual to decadal resolution
that have been shown to relate to the local temperature.
The new reconstruction shows a very cold Little Ice Age
centered around the 17th century with a cold extremum
(for 50-yr smoothing) of about 1.1 K below the temperature
of the calibration period, AD 1880-1960. This cooling is about
twice as large as corresponding numbers reported by most other
reconstructions. In the beginning of the millennium the new
reconstruction shows small anomalies in agreement with previous
studies. However, the new temperature reconstruction decreases
faster than previous reconstructions in the first 600 years
of the millennium and has a stronger variability. The salient
features of the new reconstruction are shown to be robust
to changes in the calibration period, the source of the local
temperatures, the spatial averaging procedure, and the screening
process applied to the proxies. An ensemble pseudoproxy approach
is applied to estimate the confidence intervals of the 50-yr
smoothed reconstruction showing that the period AD 1500-1850
is significantly colder than the calibration period.
STUDY NOTES: 1000 year temperature reconstruction for the Northern Hemisphere
extratropical region (30°N-90°N) by the LOC method. The new LOC
method reconstructs the local temperatures at the locations
of the proxies. The reconstruction is based on one-dimensional
linear regression with the local temperature as the independent
variable and the proxy as the dependent variable. The local
reconstructed temperatures are then averaged to get the NH mean
temperature. While this method preserves low-frequency variability,
the drawback is an exaggerated high-frequency variability.
This adverse effect can be dampened by temporal averaging
and decreases with the number of (independent) proxies.
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/christiansen2011/christiansen2011.xls
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/christiansen2011/christiansen2011.txt
USA/NOAA
DIF
Version 9.8.4
2018-12-11
2018-12-11