Bo Christiansen - Danish Meteorological Institute
Fredrik Charpentier Ljungquist - Stockholm University
We present two new multi-proxy reconstructions of the extra-tropical Northern Hemisphere (30-90°N) mean temperature: a two-millennia long reconstruction reaching back to 1 AD and a 500-yr long reconstruction reaching back to 1500 AD. The reconstructions are based on compilations of 32 and 91 proxies, respectively, of which only little more than half pass a screening procedure and are included in the actual reconstructions. The proxies are of different types and of different resolutions (annual, annual-to-decadal, and decadal) but all have previously been shown to relate to local or regional temperature. We use a reconstruction method, LOCal (LOC), that recently has been shown to confidently reproduce low-frequency variability. Confidence intervals are obtained by an ensemble pseudo-proxy method that both estimates the variance and the bias of the reconstructions. The two-millennia long reconstruction shows a well defined Medieval Warm Period, with a peak warming ca. 950-1050AD reaching 0.6°C relative to the reference period 1880-1960 AD. The 500-yr long reconstruction confirms previous results... Show more..
The dataset can be downloaded from:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/christiansen2012/christiansen2012.txt Show less..
Data contains personal data
Time period(s) investigated
Christiansen, B., and Ljungqvist, F.C. 2012: The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability. Climate of the Past, 8: 765-786, www.clim-past.net/8/765/2012/, doi:10.5194/cp-8-765-2012.
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