{"NOAAStudyId":"11937","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":"2011-08-07","dataPublisher":"NOAA","dataType":"SPELEOTHEMS","dataTypeInformation":"https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/speleothem","difMetadataLink":"http://www1.ncdc.noaa.gov/pub/data/metadata/published/paleo/dif/xml/noaa-cave-11937.xml","doi":null,"earliestYearBP":875,"earliestYearCE":1075,"entryId":"noaa-cave-11937","funding":[{"fundingAgency":"US National Science Foundation","fundingGrant":"ATM 0823554"}],"investigators":"Sinha, A.; Berkelhammer, M.B.; Stott, L.D.; Mudelsee, M.; Cheng, H.; Biswas, J.","mostRecentYearBP":-58,"mostRecentYearCE":2008,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/11937","originalSource":null,"publication":[{"abstract":"The \"internally\" generated intraseasonal variability of the Indian \r\nSummer Monsoon is characterized by intermittent periods of enhanced \r\n(\"active\") and deficient (\"break\") precipitation, which produce a \r\nquasi east-west precipitation dipole over the Indian subcontinent. \r\nHere we present multicentennial-length and near annually-resolved \r\nreconstructions of monsoon precipitation, inferred from absolute-dated \r\nand instrumentally calibrated speleothem oxygen isotope records from \r\nregions (central and northeast India) that have diametric responses \r\nto active-break monsoon circulation patterns. On centennial timescales \r\n(AD 1400-2008), precipitation variability from these two regions \r\nexhibit opposing behavior, oscillating between periods with \r\na persistently \"active-dominated\" (AD ~1700 to 2007) and a \"break-\r\ndominated\" (AD 1400 to ~1700) regime. The switch between these \r\nregimes occurs abruptly (within decades) at a time (AD ~1650-1700) \r\nwhen a proxy record of upwelling intensity from the Arabian Sea \r\nsuggest an abrupt increase in the monsoon winds. On the basis of \r\nthese observations, we hypothesize that the frequency distribution \r\nof active-break periods varies on centennial timescales, implying \r\na leading role of internal dynamics in governing the ISM response \r\nto slowly-evolving changes in the external boundary conditions. \r\n","author":null,"citation":"Sinha, A., M. Berkelhammer, L. Stott, M. Mudelsee, \r\nH. Cheng, and J. Biswas. 2011. \r\nThe leading mode of Indian Summer Monsoon precipitation \r\nvariability during the last millennium. \r\nGeophysical Research Letters, Vol. 38, L15703, \r\ndoi:10.1029/2011GL047713","edition":null,"identifier":{"id":"10.1029/2011GL047713","type":"doi","url":"http://dx.doi.org/10.1029/2011GL047713"},"issue":null,"journal":"Geophysical Research Letters","pages":null,"pubRank":"1","pubYear":2011,"reportNumber":null,"title":"The leading mode of Indian Summer Monsoon precipitation  variability during the last millennium","type":"publication","volume":null}],"reconstruction":"N","scienceKeywords":["Monsoon"],"site":[{"NOAASiteId":"52350","geo":{"geoType":"Feature","geometry":{"coordinates":["18.8667","81.8667"],"type":"POINT"},"properties":{"easternmostLongitude":"81.8667","maxElevationMeters":"600","minElevationMeters":"600","northernmostLatitude":"18.8667","southernmostLatitude":"18.8667","westernmostLongitude":"81.8667"}},"locationName":"Continent>Asia>Southcentral Asia>India","mappable":"Y","paleoData":[{"NOAADataTableId":"20255","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>speleothems>oxygen isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/india/jhumar-wah-shikar2011.txt","linkText":"jhumar-wah-shikar2011.txt","urlDescription":"Speleothem","variables":[{"cvAdditionalInfo":null,"cvDataType":"SPELEOTHEMS","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":"SPELEOTHEMS","cvDetail":"raw","cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>identified mineral>carbonate>calcium carbonate","cvMethod":"isotope ratio mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil VPDB","cvWhat":"chemical composition>isotope>isotope ratio>delta 18O"}]},{"NOAAKeywords":["earth science>paleoclimate>speleothems>oxygen isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/india/jhumar-wah-shikar2011.xls","linkText":"jhumar-wah-shikar2011.xls","urlDescription":"Speleothem","variables":[]}],"dataTableName":"JHU-1","dataTableNotes":null,"earliestYear":1075,"earliestYearBP":875,"earliestYearCE":1075,"mostRecentYear":2008,"mostRecentYearBP":-58,"mostRecentYearCE":2008,"species":[],"timeUnit":"AD"}],"siteName":"Jhumar Cave"},{"NOAASiteId":"52351","geo":{"geoType":"Feature","geometry":{"coordinates":["25.25","91.8667"],"type":"POINT"},"properties":{"easternmostLongitude":"91.8667","maxElevationMeters":"1290","minElevationMeters":"1290","northernmostLatitude":"25.25","southernmostLatitude":"25.25","westernmostLongitude":"91.8667"}},"locationName":"Continent>Asia>Southcentral Asia>India","mappable":"Y","paleoData":[{"NOAADataTableId":"20256","coreLengthMeters":null,"dataFile":[{"NOAAKeywords":["earth science>paleoclimate>speleothems>oxygen isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/india/jhumar-wah-shikar2011.txt","linkText":"jhumar-wah-shikar2011.txt","urlDescription":"Speleothem","variables":[{"cvAdditionalInfo":null,"cvDataType":"SPELEOTHEMS","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":"SPELEOTHEMS","cvDetail":"raw","cvError":null,"cvFormat":"Numeric","cvMaterial":"geological material>identified mineral>carbonate>calcium carbonate","cvMethod":"isotope ratio mass spectrometry","cvSeasonality":null,"cvShortName":null,"cvUnit":"per mil VPDB","cvWhat":"chemical composition>isotope>isotope ratio>delta 18O"}]},{"NOAAKeywords":["earth science>paleoclimate>speleothems>oxygen isotopes"],"fileUrl":"https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/asia/india/jhumar-wah-shikar2011.xls","linkText":"jhumar-wah-shikar2011.xls","urlDescription":"Speleothem","variables":[]}],"dataTableName":"WS-B","dataTableNotes":null,"earliestYear":1399,"earliestYearBP":551,"earliestYearCE":1399,"mostRecentYear":2006,"mostRecentYearBP":-56,"mostRecentYearCE":2006,"species":[],"timeUnit":"AD"}],"siteName":"Wah Shikar Cave"}],"studyCode":null,"studyName":"Central and Northeast India 1000 Year Stalagmite Oxygen Isotope Data ","studyNotes":"Stalagmite oxygen isotope (d18O) data from two caves located \nin central and northeast India, plus a composite Core Monsoon \nZone stalagmite d18O record, composed of Jhumar Cave d18O data \ncombined with previously published Dandak Cave d18O data. \n\nThe instrumentally calibrated stalagmite oxygen isotope record \n(JHU-1) from Jhumar Cave in Central India provides a millennial \nlength (AD 1075 to 2007) history of monsoon rainfall variations \nover the core monsoon zone of India (CMZ).  The record contains \n642 oxygen isotope measurements with an average temporal \nresolution of 1.45 years and its chronology is established by \ncounting annual growth layers.  A maximum uncertainty of ~10 \nyears at the bottom of the stalagmite is inferred from multiple \ncounts of growth laminae.  A suite of 230Th dates were also \nobtained to test the annual nature of the laminations (Table S2). \nWhile all 230Th ages fall on or near the slope that describe the \nlaminae-based age model, we did not use 230Th dates in constructing \nthe age model because of high detrital thorium of JHU-1 stalagmite, \nwhich produced substantially large error in 230Th dates \n(2 sigma > 200 years). \n\nThe multicentennial-length (AD 1399 to 2007) speleothem d18O record \n(WS-B) from Wah Shikar Cave in northeast India is established by \n625 d18O measurements with an average temporal resolution of 0.97 \nyears (Table S1). The record provides a history of monsoon rainfall \nvariations over northeast India (NEI). The age model for the WS-B \nstalagmite is developed from seven 230Th dates, which are in correct \nstratigraphic order, with 2 sigma error ranging from 28 to 70 years \n(Table S2). Four additional 230Th dates produced unreasonably high \nerror (> 100 years) and were subsequently discarded. The age model \nis developed by linearly interpolating between individual dates \nexcept for the segment between the bottom two dates where we \ncalculated the age at the bottom of the stalagmite by extrapolating \nthe age-depth curve from two prior better-constrained dates. \n\nThe Jhumar Cave stalagmite d18O data provides a history of monsoon \nrainfall variations over the core monsoon zone of India (CMZ). \nThe record complements our previously reported millennial-length \n(AD 625 to 1562), absolute-dated oxygen isotope record (DAN-D) \nfrom Dandak Cave (Berkelhammer et al., 2009; Sinha et al, 2007), \nwhich is located ~20 km west of Jhumar Cave. Both oxygen isotope \ntime series were linearly interpolated to an annual timescale \nand averaged (over the period of overlap) to produce a composite \noxygen isotope record that provides a continuous history of the \nCMZ's monsoon rainfall variations over the past ~1400 years \n(AD 2007-625) (Table S1). The composite record captures nearly \nevery major drought during the instrumental period as well as \nhistoric failures of monsoon, including extended intervals of \nsubstantially weaker monsoon during the 14th and 17th century. \nThe latter are independently corroborated by historical accounts \nand other regional proxy records. \n\nSite Locations:\nJhumar Cave, Central India: 18°52'N, 81°52'E, 600 masl \nWah Shikar Cave, Northeast India: 25°15'N, 91°52'E, 1290 masl \nDandak Cave: 19°N, 82°E, 400 masl   \n\n\n","version":"1.0","xmlId":"10040"}