{"NOAAStudyId":"17820","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":"1997-11-30","dataPublisher":"NOAA","dataType":"ICE CORES","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/ice-core","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-icecore-17820.xml","doi":null,"earliestYearBP":50000,"earliestYearCE":-48050,"entryId":"noaa-icecore-17820","funding":[],"investigators":"Alley, R.B.; Shuman, C.A.; Meese, D.A.; Gow, A.J.; Taylor, K.C.; Cuffey, K.M.; Fitzpatrick, J.J.; Grootes, P.M.; Zielinski, G.A.; Ram, M.; Spinelli, G.; Elder, B.","mostRecentYearBP":0,"mostRecentYearCE":1950,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/17820","originalSource":null,"publication":[{"abstract":"Annual layers are visible in the Greenland Ice Sheet Project 2 ice core from central Greenland, allowing rapid dating of the core. Changes in bubble and grain structure caused by near-surface, primarily summertime formation of hoar complexes provide the main visible annual marker in the Holocene, and changes in \"cloudiness\" of the ice correlated with dustiness mark Wisconsinan annual cycles; both markers are evident and have been intercalibrated in early Holocene ice. Layer counts are reproducible between different workers and for one worker at different times, with 1% error over century-length times in the Holocene. Reproducibility is typically 5% in Wisconsinan ice-age ice and decreases with increasing age and depth. Cumulative ages from visible stratigraphy are not significantly different from independent ages of prominent events for ice older than the historical record and younger than approximately 50,000 years. Visible observations are not greatly degraded by \"brittle ice\" or many other core-quality problems, allowing construction of long, consistently sampled time series. High accuracy requires careful study of the core by dedicated observers.","author":{"name":"R. B. Alley, C. A. Shuman, D. A. Meese, A. J. Gow, K. C. Taylor, K. M. Cuffey, J. J. Fitzpatrick, P. M. Grootes, G. A. Zielinski, M. Ram, G. Spinelli, B. Elder"},"citation":"R. B. Alley, C. A. Shuman, D. A. Meese, A. J. Gow, K. C. Taylor, K. M. Cuffey, J. J. Fitzpatrick, P. M. Grootes, G. A. Zielinski, M. Ram, G. Spinelli, B. Elder. 1997. Visual-stratigraphic dating of the GISP2 ice core: Basis, reproducibility, and application. Journal of Geophysical Research: Oceans, 102(C12), 26367-26381. doi: 10.1029/96JC03837","edition":null,"identifier":{"id":"10.1029/96JC03837","type":"doi","url":"http://dx.doi.org/10.1029/96JC03837"},"issue":"C12","journal":"Journal of Geophysical Research: Oceans","pages":"26367-26381","pubRank":"1","pubYear":1997,"reportNumber":null,"title":"Visual-stratigraphic dating of the GISP2 ice core: Basis, reproducibility, and application","type":"publication","volume":"102"}],"reconstruction":"N","scienceKeywords":null,"site":[{"NOAASiteId":"19978","geo":{"geoType":"Feature","geometry":{"coordinates":["72.6","-38.5"],"type":"POINT"},"properties":{"easternmostLongitude":"-38.5","maxElevationMeters":"3200","minElevationMeters":"3200","northernmostLatitude":"72.6","southernmostLatitude":"72.6","westernmostLongitude":"-38.5"}},"locationName":"Continent>North America>Greenland","mappable":"Y","paleoData":[{"NOAADataTableId":"28139","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>ice core>physical properties"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/physical/visual.txt","linkText":"GISP2 Visual Stratigraphy","urlDescription":"Data File","variables":[]},{"NOAAKeywords":["earth science>paleoclimate>ice core>physical properties"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/physical/strat.txt","linkText":"GISP2 Stratigraphy","urlDescription":"Data File","variables":[{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":"based on ECM","cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":"based on visual strat","cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"depth variable>depth"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"year Common Era","cvWhat":"age variable>age>ice age"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"hydrologic material>bulk ice","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"physical property>length>layer thickness"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"hydrologic material>bulk ice","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"gram per cubic centimeter","cvWhat":"physical property>density"},{"cvAdditionalInfo":"water equivalent","cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"hydrologic material>bulk ice","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter","cvWhat":"physical property>length>layer thickness"},{"cvAdditionalInfo":"accumulation rate/layer thickness","cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":null,"cvWhat":"sampling metadata>notes"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":null,"cvWhat":"sampling metadata>notes"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":"hydrologic material>bulk ice","cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"meter per year","cvWhat":"formation property>formation rate>accumulation rate"},{"cvAdditionalInfo":null,"cvDataType":"ICE CORES","cvDetail":null,"cvError":null,"cvFormat":"Numeric","cvMaterial":null,"cvMethod":null,"cvSeasonality":null,"cvShortName":null,"cvUnit":"calendar year before present","cvWhat":"age variable>age>ice age"}]}],"dataTableName":"GISP21997strat","dataTableNotes":null,"earliestYear":50000,"earliestYearBP":50000,"earliestYearCE":-48050,"mostRecentYear":0,"mostRecentYearBP":0,"mostRecentYearCE":1950,"species":[],"timeUnit":"cal yr BP"}],"siteName":"GISP2"}],"studyCode":null,"studyName":"GISP2 Ice Core Stratigraphy","studyNotes":"Depths of mid-summer as determined separately from ECM\nand visual stratigraphy in the GISP2-D ice core.  Also given are\ncalculated layer thicknesses (true and ice equivalent) and calculated\naccumulation rates, all in meters.  ","version":"1.0","xmlId":"15508"}