{"NOAAStudyId":"12902","contactInfo":{"address":"325 Broadway, E/NE31","city":"Boulder","constraints":"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.","country":"USA","dataCenterUrl":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data","email":"paleo@noaa.gov","fax":"303-497-6513","longName":"National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce ","phone":"303-497-6280","postalCode":"80305-3328","shortName":"DOC/NOAA/NESDIS/NCEI","state":"CO","type":"CONTACT INFORMATION"},"contributionDate":"2012-04-19","dataPublisher":"NOAA","dataType":"CLIMATE RECONSTRUCTIONS","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/climate-reconstruction","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-recon-12902.xml","doi":null,"earliestYearBP":1950,"earliestYearCE":0,"entryId":"noaa-recon-12902","funding":[{"fundingAgency":"Danish Meteorological Institute","fundingGrant":null}],"investigators":"Christiansen, B.; Ljungqvist, F.C.","mostRecentYearBP":-23,"mostRecentYearCE":1973,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/12902","originalSource":null,"publication":[{"abstract":"We present two new multi-proxy reconstructions of the extra-tropical \r\nNorthern Hemisphere (30-90°N) mean temperature: a two-millennia long \r\nreconstruction reaching back to 1AD and a 500-yr long reconstruction \r\nreaching back to 1500 AD. The reconstructions are based on compilations\r\nof 32 and 91 proxies, respectively, of which only little more than half \r\npass a screening procedure and are included in the actual reconstructions. \r\nThe proxies are of different types and of different resolutions (annual, \r\nannual-to-decadal, and decadal) but all have previously been shown to \r\nrelate to local or regional temperature. We use a reconstruction method, \r\nLOCal (LOC), that recently has been shown to confidently reproduce \r\nlow-frequency variability. Confidence intervals are obtained by an \r\nensemble pseudo-proxy method that both estimates the variance and the \r\nbias of the reconstructions. The two-millennia long reconstruction \r\nshows a well defined Medieval Warm Period, with a peak warming \r\nca. 950-1050AD reaching 0.6°C relative to the reference period \r\n1880-1960 AD. The 500-yr long reconstruction confirms previous results \r\nobtained with the LOC method applied to a smaller proxy compilation; \r\nin particular it shows the Little Ice Age cumulating in 1580-1720AD \r\nwith a temperature minimum of -1.0°C below the reference period. \r\nThe reconstructed local temperatures, the magnitude of which are\r\nsubject to wide confidence intervals, show a rather geographically\r\nhomogeneous Little Ice Age, while more geographical inhomogeneities \r\nare found for the Medieval Warm Period. Reconstructions based on \r\ndifferent subsets of proxies show only small differences, suggesting \r\nthat LOC reconstructs 50-yr smoothed extra-tropical NH mean temperatures\r\nwell and that low-frequency noise in the proxies is a relatively small \r\nproblem.","author":null,"citation":"Christiansen, B. and F.C. Ljungqvist. 2012. \r\nThe extra-tropical Northern Hemisphere temperature in the last \r\ntwo millennia: reconstructions of low-frequency variability. \r\nClimate of the Past, Vol. 8, pp. 765-786. \r\nwww.clim-past.net/8/765/2012/ \r\ndoi:10.5194/cp-8-765-2012","edition":null,"identifier":{"id":"10.5194/cp-8-765-2012","type":"doi","url":"http://dx.doi.org/10.5194/cp-8-765-2012"},"issue":null,"journal":"Climate of the Past","pages":null,"pubRank":"1","pubYear":2012,"reportNumber":null,"title":"The extra-tropical Northern Hemisphere temperature in the last  two millennia: reconstructions of low-frequency variability","type":"publication","volume":null}],"reconstruction":"Y","scienceKeywords":["Medieval Warm Period","Air Temperature Reconstruction","Little Ice Age (LIA)"],"site":[{"NOAASiteId":"52563","geo":{"geoType":"Feature","geometry":{"coordinates":["30","90","-180","180"],"type":"POLYGON"},"properties":{"easternmostLongitude":"180","maxElevationMeters":null,"minElevationMeters":null,"northernmostLatitude":"90","southernmostLatitude":"30","westernmostLongitude":"-180"}},"locationName":"Geographic Region>Northern Hemisphere","mappable":"N","paleoData":[{"NOAADataTableId":"21244","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>reconstructions>air temperature"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/christiansen2012/christiansen2012.txt","linkText":"christiansen2012.txt","urlDescription":"Original Data and Full Metadata","variables":[{"cvAdditionalInfo":null,"cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"year Common Era","cvWhat":"age variable>age"},{"cvAdditionalInfo":"anomalized wrt 1880-1960 AD; thin black curve in Fig 5","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"anomalized","cvError":null,"cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"},{"cvAdditionalInfo":"anomalized wrt 1880-1960 AD; thick black curve in Fig 5; 50 year smooth","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"smoothed","cvError":null,"cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"},{"cvAdditionalInfo":"anomalized wrt 1880-1960 AD; thick black curve in Fig 5; 50 year smooth","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"anomalized","cvError":null,"cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"},{"cvAdditionalInfo":"anomalized wrt 1880-1960 AD; thick red curve in Fig 5; 50 year smooth plus bias","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"smoothed","cvError":null,"cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"},{"cvAdditionalInfo":"anomalized wrt 1880-1960 AD; thick red curve in Fig 5; 50 year smooth plus bias","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"anomalized","cvError":null,"cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"},{"cvAdditionalInfo":"97.5th percentile; anomalized wrt 1880-1960 AD; dashe red curve in Fig 5; 50 year smooth","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"smoothed","cvError":"percentile","cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"},{"cvAdditionalInfo":"97.5th percentile; anomalized wrt 1880-1960 AD; dashe red curve in Fig 5; 50 year smooth","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"anomalized","cvError":"percentile","cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"},{"cvAdditionalInfo":"2.5th percentile; anomalized wrt 1880-1960 AD; dashe red curve in Fig 5; 50 year smooth","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"smoothed","cvError":"percentile","cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"},{"cvAdditionalInfo":"2.5th percentile; anomalized wrt 1880-1960 AD; dashe red curve in Fig 5; 50 year smooth","cvDataType":"CLIMATE RECONSTRUCTIONS","cvDetail":"anomalized","cvError":"percentile","cvFormat":"Numeric","cvMaterial":"reconstruction material>multiple proxies","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"degree Celsius","cvWhat":"earth system variable>temperature variable>temperature"}]},{"NOAAKeywords":["earth science>paleoclimate>reconstructions>air temperature"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/christiansen2012/christiansen2012.xls","linkText":"christiansen2012.xls","urlDescription":"Original Data and Full Metadata","variables":[]}],"dataTableName":"CL2012","dataTableNotes":null,"earliestYear":0,"earliestYearBP":1950,"earliestYearCE":0,"mostRecentYear":1973,"mostRecentYearBP":-23,"mostRecentYearCE":1973,"species":[],"timeUnit":"AD"}],"siteName":"Northern Hemisphere Extratropics"}],"studyCode":null,"studyName":"Northern Hemisphere Extratropical 2000 Year Temperature Reconstruction","studyNotes":"2000 year and 500 year temperature reconstructions for the Northern \nHemisphere extratropical region (30°N-90°N) by the LOC method.  \nThe LOC method reconstructs the local temperatures at the locations \nof the proxies. The reconstruction is based on one-dimensional \nlinear regression with the local temperature as the independent \nvariable and the proxy as the dependent variable. The local \nreconstructed temperatures are then averaged to get the NH mean \ntemperature. While this reconstruction method, LOC, is expected \nto catch the 50-year smoothed variability well, it exaggerates \nhigh-frequency variability.  Hence, users are recommended to use \nthe 50Yr-smoothed values for both the 2000-year long and 500-year \nlong reconstructions. ","version":"1.0","xmlId":"10966"}