WAIS Divide Ice Core 2400 Year Sulfate and Nitrate Isotope Data Sofen, E.D.; Alexander, B.; Steig, E.J.; Thiemens, M.H.; Kunasek, S.A.; Amos, H.M.; Schauer, A.J.; Hastings, M.G.; Bautista, J.; Jackson, T.L.; Vogel, L.E.; McConnell, J.R.; Pasteris, D.R.; Saltzman, E.S. Sofen, E.D. Alexander, B. Steig, E.J. Thiemens, M.H. Kunasek, S.A. Amos, H.M. Schauer, A.J. Hastings, M.G. Bautista, J. Jackson, T.L. Vogel, L.E. McConnell, J.R. Pasteris, D.R. Saltzman, E.S. earth science/paleoclimate/ice cores (notes,null,null,null,null,ice cores,null,null,C,null) earth science/paleoclimate/ice cores (depth at sample start,null,null,meter,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (delta 15N,nitrate,one standard deviation,per mil AIR,null,ice cores,averaged,continuous-flow isotope ratio mass spectrometry,N,null) earth science/paleoclimate/ice cores (nitrate,bulk ice,null,parts per billion,null,ice cores,averaged,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/ice cores (delta 17O excess,sulfate,null,per mil SMOW,null,ice cores,averaged|corrected,continuous-flow isotope ratio mass spectrometry,N,corrected: isotopic exchange with quartz) earth science/paleoclimate/ice cores (methanesulfonic acid,bulk ice,null,parts per billion,null,ice cores,averaged,electrospray ionization mass spectrometry,N,null) earth science/paleoclimate/ice cores (delta 17O excess,nitrate,null,per mil VSMOW,null,ice cores,averaged,null,N,null) earth science/paleoclimate/ice cores (delta 18O,bulk ice,null,per mil VSMOW,null,ice cores,averaged,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/ice cores (depth at sample end,null,null,meter,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (delta 17O excess,nitrate,one standard deviation,per mil VSMOW,null,ice cores,averaged,continuous-flow isotope ratio mass spectrometry,N,null) earth science/paleoclimate/ice cores (delta 17O excess,sulfate,null,per mil SMOW,null,ice cores,averaged,continuous-flow isotope ratio mass spectrometry,N,null) earth science/paleoclimate/ice cores (delta 17O excess,nitrate,one standard deviation,per mil VSMOW,null,ice cores,averaged,null,N,null) earth science/paleoclimate/ice cores (delta 15N,nitrate,one standard deviation,per mil AIR,null,ice cores,averaged,null,N,null) earth science/paleoclimate/ice cores (accumulation rate,bulk ice,null,centimeter per year,null,ice cores,averaged,null,N,water equivalent) earth science/paleoclimate/ice cores (delta 17O excess,sulfate,one standard deviation,per mil SMOW,null,ice cores,averaged,continuous-flow isotope ratio mass spectrometry,N,null) earth science/paleoclimate/ice cores (accumulation rate,bulk ice,null,centimeter per year,null,ice cores,averaged,null,N,null) earth science/paleoclimate/ice cores (sulfur,bulk ice,null,parts per billion,null,ice cores,averaged,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/ice cores (acidity,bulk ice,null,micromole,null,ice cores,averaged,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/ice cores (age at sample end,null,null,year Common Era,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (delta 17O excess,nitrate,null,per mil VSMOW,null,ice cores,averaged,continuous-flow isotope ratio mass spectrometry,N,null) earth science/paleoclimate/ice cores (hydrogen peroxide,bulk ice,null,parts per billion,null,ice cores,averaged,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/ice cores (sulfate,bulk ice,null,nanogram per gram,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (age at sample start,null,null,year Common Era,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (sodium,bulk ice,null,parts per billion,null,ice cores,averaged,inductively-coupled plasma mass spectrometry,N,null) earth science/paleoclimate/ice cores (delta 15N,nitrate,null,per mil AIR,null,ice cores,averaged,continuous-flow isotope ratio mass spectrometry,N,null) earth science/paleoclimate/ice cores (sodium,bulk ice,null,nanogram per gram,null,ice cores,null,continuous flow analysis,N,null) earth science/paleoclimate/ice cores (sea salt,bulk ice,null,fraction,null,ice cores,null,null,N,fraction of total sulfate) earth science/paleoclimate/ice cores (delta 17O excess,non-sea-salt sulfate,null,per mil VSMOW,null,ice cores,corrected,null,N,corrected: isotopic exchange with quartz) earth science/paleoclimate/ice cores (delta 15N,nitrate,null,per mil AIR,null,ice cores,averaged,null,N,null) earth science/paleoclimate/ice core earth science/paleoclimate/ice core (WAIS Divide WDC06A>LATITUDE -79.4676>LONGITUDE -112.0865) (WAIS Divide WDC05A>LATITUDE -79.47>LONGITUDE -112.13) (WAIS Divide WDC05Q>LATITUDE -79.47>LONGITUDE -112.08) The 17O excess (D17O = d17O-0.52 x d18O) of sulfate and nitrate reflects the relative importance of their different production pathways in the atmosphere. A new record of sulfate and nitrate D17O spanning the last 2400 years from the West Antarctic Ice Sheet Divide ice core project shows significant changes in both sulfate and nitrate D17O in the most recent 200 years, indicating changes in their formation pathways. The sulfate D17O record exhibits a 1.1 per mil increase in the early 19th century from (2.4 +/- 0.2) per mil to (3.5 +/- 0.2) per mil, which suggests that an additional 12-18% of sulfate formation occurs via aqueous-phase production by O3, relative to that in the gas phase. Nitrate D17O gradually decreases over the whole record, with a more rapid decrease between the mid-19th century and the present day of 5.6 per mil, indicating an increasing importance of RO2 in NOx cycling between the mid-19th century and the present day in the mid- to high-latitude Southern Hemisphere. The former has implications for the climate impacts of sulfate aerosol, while the latter has implications for the tropospheric O3 production rate in remote low-NOx environments. Using other ice core observations, we rule out drivers for these changes other than variability in extratropical oxidant (OH, O3, RO2, H2O2, and reactive halogens) concentrations. However, assuming OH, H2O2, and O3 are the main oxidants contributing to sulfate formation, Monte Carlo box model simulations require a large (>= 260%) increase in the O3 /OH mole fraction ratio over the Southern Ocean in the early 19th century to match the sulfate D17O record. This unlikely scenario points to a~deficiency in our understanding of sulfur chemistry and suggests other oxidants may play an important role in sulfate formation in the mid- to high-latitude marine boundary layer. The observed decrease in nitrate D17O since the mid-19th century is most likely due to an increased importance of RO2 over O3 in NOx cycling and can be explained by a 60-90% decrease in the O3 / RO2 mole fraction ratio in the extratropical Southern Hemisphere NOx-source regions. STUDY NOTES: Isotopic composition of sulfate and nitrate from 3 WAIS Divide Ice Cores. Data set updated 10/7/2014 to add age model, correct citation, and add additional data (accumulation, MSA, NO3-, H2O2, Sulfur, Acid, NA+, water d18O). NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Sofen, E.D. Investigator : Alexander, B. Investigator : Steig, E.J. Investigator : Thiemens, M.H. Investigator : Kunasek, S.A. Investigator : Amos, H.M. Investigator : Schauer, A.J. Investigator : Hastings, M.G. Investigator : Bautista, J. Investigator : Jackson, T.L. Investigator : Vogel, L.E. Investigator : McConnell, J.R. Investigator : Pasteris, D.R. Investigator : Saltzman, E.S. 2013-03-28 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/14172 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013so4no3iso.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013d17o.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013sulfate-nitrate-d17o.xlsx https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013d15n.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013so4no3iso.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013d17o.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013sulfate-nitrate-d17o.xlsx https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013d15n.txt English https://www.ncdc.noaa.gov/paleo/study/14172 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013so4no3iso.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013d17o.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013sulfate-nitrate-d17o.xlsx https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/wais2013d15n.txt Sofen, E.D., B. Alexander, E.J. Steig, M.H. Thiemens, S.A. Kunasek, H.M. Amos, A.J. Schauer, M.G. Hastings, J. Bautista, T.L. Jackson, L.E. Vogel, J.R. McConnell, D.R. Pasteris, and E.S. Saltzman2014WAIS Divide ice core record suggests sustained changes in the chemical formation pathways of sulfate and nitrate aerosol since the 19th centuryAtmospheric Chemistry and Physics14115749-576910.5194/acp-14-5749-2014http://www.atmos-chem-phys.net/14/5749/2014/acp-14-5749-2014.html START YEAR: -427 AD * END YEAR: 2008 AD -112.13 -79.47 -112.08 -79.4676