{"NOAAStudyId":"6192","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":"2009-04-01","dataPublisher":"NOAA","dataType":"PALEOLIMNOLOGY","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/lake","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-lake-6192.xml","doi":null,"earliestYearBP":1941,"earliestYearCE":9,"entryId":"noaa-lake-6192","funding":[],"investigators":"Bird, B.W.; Abbott, M.B.; Finney, B.P.; Kutchko, B.","mostRecentYearBP":-55,"mostRecentYearCE":2005,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/6192","originalSource":null,"publication":[{"abstract":"Varved minerogenic sediments from glacial-fed Blue Lake, northern Alaska, are used to investigate late Holocene climate variability. Varve-thickness measurements track summer temperature recorded at Atigun Pass, located 41 km east at a similar elevation (r 2 = 0.31, P = 0.08). Results indicate that climate in the Brooks Range from 10 to 730 AD (varve year) was warm with precipitation inferred to be higher than during the twentieth century. The varve-temperature relationship for this period was likely compromised and not used in our temperature reconstruction because the glacier was greatly reduced, or absent, exposing sub-glacial sediments to erosion from enhanced precipitation. Varve-inferred summer temperatures and precipitation decreased after 730 AD, averaging 0.4°C above the last millennial average (LMA = 4.2°C) from 730 to 850 AD, and 0.1°C above the LMA from 850 to 980 AD. Cooling culminated between 980 and 1030 AD with temperatures 0.7°C below the LMA. Varve-inferred summer temperatures increased between 1030 and 1620 AD to the LMA, though the period between 1260 and 1350 AD was 0.2°C below the LMA. Although there is no equivalent to the European Medieval Warm Period in the Blue Lake record, two warm intervals occurred from 1350 to 1450 AD and 1500 to 1620 AD (0.4 and 0.3°C above the LMA, respectively). During the Little Ice Age (LIA; 1620 to 1880 AD), inferred summer temperature averaged 0.2°C below the LMA. After 1880 AD, inferred summer temperature increased to 0.8°C above the LMA, glaciers retreated, but aridity persisted based on a number of regional paleoclimate records. Despite warming and glacial retreat, varve thicknesses have not achieved pre-730 AD levels. This reflects limited sediment availability and transport due to a less extensive retreat compared to the first millennium, and continued relative aridity. Overall, the Blue Lake record is similar to varve records from the eastern Canadian Arctic that document a cool LIA and twentieth century warming. However, the occurrence and timing of events, such as the LIA and Medieval Warm Period, varies considerably among records, suggesting heterogeneous climatic patterns across the North American Arctic.","author":null,"citation":"Bird, B.W.,Abbott, M.B.,Finney, B.P.,Kutchko, B. 2008. A 2000 year varve-based climate record from the central Brooks Range, Alaska. Journal of Paleolimnology, 41(1), 25-41.","edition":null,"identifier":null,"issue":null,"journal":"Journal of Paleolimnology","pages":null,"pubRank":"1","pubYear":2008,"reportNumber":null,"title":"A 2000 year varve-based climate record from the central Brooks Range, Alaska","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"20658","geo":{"geoType":"Feature","geometry":{"coordinates":["68.0869","-150.465"],"type":"POINT"},"properties":{"easternmostLongitude":"-150.465","maxElevationMeters":"1275","minElevationMeters":"1275","northernmostLatitude":"68.0869","southernmostLatitude":"68.0869","westernmostLongitude":"-150.465"}},"locationName":"Continent>North America>United States Of America>Alaska","mappable":"Y","paleoData":[{"NOAADataTableId":"9502","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>paleolimnology>physical properties"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/blue2008.txt","linkText":"blue2008.txt","urlDescription":"Data","variables":[{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"year Common Era","cvWhat":"age variable>age"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"centimeter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment>dry sediment","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"gram per cubic centimeter","cvWhat":"physical property>density"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"weight percent","cvWhat":"biological material>bulk biological material>organic matter"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"weight percent","cvWhat":"geological material>identified mineral>carbonate"},{"cvAdditionalInfo":"x10-6 units","cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>bulk geological material>sediment","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"dimensionless (SI system)","cvWhat":"magnetic property>magnetic moments>magnetic susceptibility>volume magnetic susceptibility"},{"cvAdditionalInfo":null,"cvDataType":"PALEOLIMNOLOGY","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"centimeter","cvWhat":"physical property>length>varve thickness"}]},{"NOAAKeywords":["earth science>paleoclimate>paleolimnology>physical properties"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/blue2008.xls","linkText":"blue2008.xls","urlDescription":"Data","variables":[]}],"dataTableName":"Blue Lake Core BLUELKAK","dataTableNotes":null,"earliestYear":1941,"earliestYearBP":1941,"earliestYearCE":9,"mostRecentYear":-55,"mostRecentYearBP":-55,"mostRecentYearCE":2005,"species":[],"timeUnit":"cal yr BP"}],"siteName":"Blue Lake"}],"studyCode":null,"studyName":"Blue Lake, Brooks Range, Alaska 2,000 Year Varve Thickness Data","studyNotes":"Varve thickness measurements and sediment physical and geochemical properties from Blue Lake, Endicott Mountains, Central Brooks Range, Alaska","version":"1.0","xmlId":"2142"}