{"NOAAStudyId":"25530","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":"2018-10-31","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-25530.xml","doi":null,"earliestYearBP":2639,"earliestYearCE":-689,"entryId":"noaa-icecore-25530","funding":[{"fundingAgency":"Dutch Organization for Scientific  Research (NWO)","fundingGrant":"851.30.020, 865.07.001"}],"investigators":"Prokopiou, M.; Sapart, C.J.; Rosen, J.; Sperlich, P.; Blunier, T.; Brook, E.J.; van de Wal, R.S.W.; Röckmann, T.","mostRecentYearBP":-58,"mostRecentYearCE":2008,"onlineResourceLink":"https://www.ncdc.noaa.gov/paleo/study/25530","originalSource":null,"publication":[{"abstract":"Nitrous oxide (N2O) is a strong greenhouse gas whose mole fraction in the atmosphere has increased over the industrial period. We present a new set of isotope measurements of N2O in air extracted from ice cores covering the last 3,000 years. For the preindustrial (PI) atmosphere, we find an average N2O mole fraction of (267 ± 1) nmol/mol and average tropospheric N2O isotopic values of d15NavPI = (9.5 ± 0.1)permil, d18OPI = (47.1 ± 0.2)permil, d15NalphaPI = (17.8 ± 0.4)permil, and d15NBetaPI = (1.2 ± 0.4)permil. From PI to modern times all isotope signatures decreased with a total change of d15Nav = (-2.7 ± 0.2)permil, d18O = (-2.5 ± 0.4)permil, d15Nalpha = (-2.0 ± 0.7)permil, and d15NBeta (-3.5 ± 0.7)permil. Interestingly, the temporal evolution is not the same for d15Nav and d18O. d18O trends are relatively larger during the early part, and d15Nav trends are larger during the late part of the industrial period, implying a decoupling of sources over the industrial period. Using a mass balance model, we determined the isotopic composition of the total average N2O source. Assuming that the total present source is the sum of a constant natural source and an increasing anthropogenic source, this anthropogenic source has an isotopic signature of d15Navsource,anthrop = (-15.0 ± 2.6)permil, d18Osource,anthrop = (30.0 ± 2.6)permil, d15Nalphasource,anthrop = (-4.5 ± 1.7)permil, and d15NBetasource,anthrop = (-24.0 ± 8.4)permil. The 15N site preference of the source has increased since PI times, which is indicative of a relative shift from denitrification to nitrification sources, consistent with agricultural emissions playing a major role in the N2O increase.","author":{"name":"M. Prokopiou, C.J. Sapart, J. Rosen, P. Sperlich, T. Blunier, E. Brook, R.S.W. van de Wal, T. Röckmann"},"citation":"M. Prokopiou, C.J. Sapart, J. Rosen, P. Sperlich, T. Blunier, E. Brook, R.S.W. van de Wal, T. Röckmann. 2018. Changes in the Isotopic Signature of Atmospheric Nitrous Oxide and Its Global Average Source During the Last Three Millennia. 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