# Vostok, Antarctica Ice Core 4G-2 61-58KYr Methane and d15N Data #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # Template Version 3.0 # Encoding: UTF-8 # NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. # If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. # # Online_Resource: https://www.ncdc.noaa.gov/paleo/study/23210 # Description: NOAA Landing Page # Online_Resource: https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/vostok2017d15n.txt # Description: NOAA location of the template # # Original_Source_URL: # Description: # # Description/Documentation lines begin with # # Data lines have no # # # Archive: Ice Core # # Dataset DOI: # # Parameter_Keywords: atmospheric gas, nitrogen isotopes #-------------------- # Contribution_Date # Date: 2017-12-07 #-------------------- # File_Last_Modified_Date # Date: 2017-12-07 #-------------------- # Title # Study_Name: Vostok, Antarctica Ice Core 4G-2 61-58KYr Methane and d15N Data #-------------------- # Investigators # Investigators: Fourteau, K.; Faïn X.; Martinerie P.; Landais A.; Ekaykin A.A.; Lipenkov V.Ya.; Chappellaz J. #-------------------- # Description_Notes_and_Keywords # Description: Vostok, Antarctica 61-58kY 4G-2 ice core d15N of N2. #-------------------- # Publication # Authors: Kévin Fourteau, Xavier Faïn, Patricia Martinerie, Amaëlle Landais, Alexey A. Ekaykin, Vladimir Ya. Lipenkov, and Jérôme Chappellaz # Published_Date_or_Year: 2017-12-13 # Published_Title: Analytical constraints on layered gas trapping and smoothing of atmospheric variability in ice under low-accumulation conditions # Journal_Name: Climate of the Past Discussions # Volume: 13 # Edition: # Issue: 12 # Pages: 1815-1830 # Report_Number: # DOI: 10.5194/cp-13-1815-2017 # Online_Resource: https://www.clim-past.net/13/1815/2017/ # Full_Citation: # Abstract: We investigate for the first time the loss and alteration of past atmospheric information from air trapping mechanisms under low-accumulation conditions through continuous CH4 (and CO) measurements. Methane concentration changes were measured over the Dansgaard-Oeschger event 17 (DO-17, - 60 000 yr BP) in the Antarctic Vostok 4G-2 ice core. Measurements were performed using continuous-flow analysis combined with laser spectroscopy. The results highlight many anomalous layers at the centimeter scale that are unevenly distributed along the ice core. The anomalous methane mixing ratios differ from those in the immediate surrounding layers by up to 50 ppbv. This phenomenon can be theoretically reproduced by a simple layered trapping model, creating very localized gas age scale inversions. We propose a method for cleaning the record of anomalous values that aims at minimizing the bias in the overall signal. Once the layered-trapping-induced anomalies are removed from the record, DO-17 appears to be smoother than its equivalent record from the high-accumulation WAIS Divide ice core. This is expected due to the slower sinking and densification speeds of firn layers at lower accumulation. However, the degree of smoothing appears surprisingly similar between modern and DO-17 conditions at Vostok. This suggests that glacial records of trace gases from low-accumulation sites in the East Antarctic plateau can provide a better time resolution of past atmospheric composition changes than previously expected. We also developed a numerical method to extract the gas age distributions in ice layers after the removal of the anomalous layers based on comparison with a weakly smoothed record. It is particularly adapted for the conditions of the East Antarctic plateau, as it helps to characterize smoothing for a large range of very low-temperature and low-accumulation conditions. #------------------ # Funding_Agency # Funding_Agency_Name: European Community Seventh Framework Programme ERC2011 # Grant: grant agreement no. 291062 (ERC Ice&Lasers) #------------------ # Funding_Agency # Funding_Agency_Name: INSU/CNRS # Grant: LEFE project NEVE-CLIMAT #------------------ # Funding_Agency # Funding_Agency_Name: Laboratoire International Associe Vostok # Grant: #------------------ # Funding_Agency # Funding_Agency_Name: LabEx OSUG@2020 # Grant: ANR10LABX56 #------------------ # Funding_Agency # Funding_Agency_Name: ENS Paris-Saclay # Grant: #------------------ # Site_Information # Site_Name: Vostok # Location: Antarctica # Country: # Northernmost_Latitude: -78.4661 # Southernmost_Latitude: -78.4661 # Easternmost_Longitude: -106.8483 # Westernmost_Longitude: -106.8483 # Elevation: 3500 m #------------------ # Data_Collection # Collection_Name: Vostok2017d15N # Earliest_Year: 60829 # Most_Recent_Year: 58118 # Time_Unit: Cal. Year BP # Core_Length: 36 m # Notes: This dataset is d15N of N2 measured along a section of the 4G-2 Vostok ice core from East Antarctica 895-931m; Earliest and most recent years were given according to the AICC2012 gas age scale; #------------------ # Chronology_Information # Chronology: # #---------------- # Variables # # Data variables follow are preceded by "##" in columns one and two. # Data line variables format: one per line, shortname-tab-variable components (what, material, error, units, seasonality, data type,detail, method, C or N for Character or Numeric data, free text) # ## depth_m depth, , , m, , , , ,N, ## d15N d15N, , ,permil, , Ice cores,,values measured by mass spectrometry in extracted air after water and CO2 trap and corrected for O2/N2 chemical slope, N, # #---------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Values: -999 # depth_m d15N 895 0.46689757 895.5 0.434223392 896 0.422907715 896.5 0.419628326 897 0.454409654 897.5 0.42034719 898 0.449366957 898.6 0.441412646 901.5 0.463233745 902 0.460676969 902.5 0.480007932 903 0.464243023 903.5 0.462577191 904.5 0.480602634 905 0.457068714 905.5 0.45135824 905.98 0.477203738 906.6 0.460946342 907 0.470206528 907.5 0.445906058 908 0.442460413 909 0.435397861 909.48 0.466720594 909.95 0.469489284 911 0.445664511 911.5 0.46008428 912 0.455 912.5 0.464132467 913.5 0.458494096 914.025 0.440777167 914.5 0.489525483 915 0.479981819 915.5 0.452762834 916 0.450198775 916.5 0.454827781 917 0.45093107 917.5 0.463470457 918 0.451000847 918.5 0.443199862 920 0.461429488 921.5 0.454274241 922 0.483041592 922.5 0.482534116 924.26 0.498459193 924.32 0.487101687 924.6 0.466168098 925 0.463508136 926 0.473306383 926.52 0.489401976 927 0.473896683 927.4 0.492276348 928 0.490741461 928.5 0.487655971 930 0.46629736 930.46 0.454394316