[{"@context":"http:\/\/schema.org\/","@type":"Dataset","identifier":"https:\/\/bolin.su.se\/data\/christiansen-2013-nh-2000-1","name":"Northern Hemisphere extratropical 2000-year and 500-year temperature reconstructions","description":"We present two new multi-proxy reconstructions of the extra-tropical Northern Hemisphere (30\u201390\u00b0N) 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\u20131050 AD reaching 0.6\u00b0C relative to the reference period 1880\u20131960 AD. The 500-yr long reconstruction confirms previous results obtained with the LOC method applied to a smaller proxy compilation; in particular it shows the Little Ice Age cumulating in 1580\u20131720 AD with a temperature minimum of -1.0\u00b0C below the reference period. The reconstructed local temperatures, the magnitude of which are subject to wide confidence intervals, show a rather geographically homogeneous Little Ice Age, while more geographical inhomogeneities are found for the Medieval Warm Period. Reconstructions based on different subsets of proxies show only small differences, suggesting that LOC reconstructs 50-yr smoothed extra-tropical NH mean temperatures well and that low-frequency noise in the proxies is a relatively small problem.","url":"http:\/\/bolin.su.se\/data\/christiansen-2013-nh-2000-1","keywords":["Atmosphere","Temperature","Northern hemisphere","Temperature","Reconstruction","Paleoclimate > Paleoclimate Reconstructions > Air Temperature Reconstruction"],"creator":{"@type":"Person","name":"Bo Christiansen, Fredrik Charpentier Ljungqvist"},"citation":"Christiansen B, Ljungqvist FC (2012) The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability. Climate of the Past, 8: 765\u2013786. DOI: 10.5194\/cp-8-765-2012","isAccessibleForFree":true,"includedInDataCatalog":{"@type":"DataCatalog","name":"Bolin Centre for Climate Research, Stockholm University","identifier":"https:\/\/bolin.su.se\/data\/","url":"https:\/\/bolin.su.se\/data\/"},"distribution":{"@type":"DataDownload","encodingFormat":false,"contentUrl":"https:\/\/bolin.su.se\/data\/https:\/\/www.ncei.noaa.gov\/pub\/data\/paleo\/contributions_by_author\/christiansen2012\/christiansen2012.txt"},"size":false,"isBasedOn":"Christiansen B, Ljungqvist FC (2012) The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability. Climate of the Past, 8: 765\u2013786. DOI: 10.5194\/cp-8-765-2012","temporalCoverage":"1000-01-01\/1000-01-01"}]