Goursaud, Sentia; Masson-Delmotte, Valerie; Favier, Vincent; Preunkert, Suzanne; Legrand, Michel R; Minster, Bénédicte (2018): The TA192A water stable isotope and chemical firn core records , Adélie Land, Antarctica. PANGAEA, https://doi.org/10.1594/PANGAEA.896623, Supplement to: Goursaud, Sentia; Masson-Delmotte, Valerie; Favier, Vincent; Preunkert, Suzanne; Legrand, Michel; Minster, Bénédicte; Werner, Martin (2019): Challenges associated with the climatic interpretation of water stable isotope records from a highly resolved firn core from Adélie Land, coastal Antarctica. The Cryosphere, 13(4), 1297-1324, https://doi.org/10.5194/tc-13-1297-2019
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A new 21.3m firn core was drilled in 2015 at a coastal Antarctic high accumulation site in Adélie Land (66.78°S; 139.56°E, 602ma.s.l.). The core was dated by annual layers counting based on non-sea-salt sulfate and methanesulfonate summer peaks, refined by a comparison between the reconstructed surface mass balance (hereafter, SMB) and the closest available stake data. The mean reconstructed SMB of 75.2 ± 15.0cmw.e. y−1 is consistent with local stake data, and remarkably high for coastal East Antarctica. The resulting inter-annual and sub-annual variations in isotopic records (δ18O and deuterium excess, hereafter d-excess) are explored for 1998–2014 and are systematically compared with a couple of climatic time series: an updated database of Antarctic surface snow isotopic composition, SMB stake data, meteorological observations from Dumont d'Urville station, sea-ice concentration based on passive microwave satellite data, precipitation outputs of atmospheric reanalyses, climate and water stable isotope outputs from the atmospheric general circulation model ECHAM5-wiso, as well as air mass origins diagnosed using 5-days back-trajectories.
The mean isotopic values (−19.3 ± 3.1‰ for δ18O and 5.4 ± 2.2‰ for d-excess) are consistent with other coastal Antarctic values. No significant isotope-temperature relationship can be evidenced at any timescale, ruling out a simple interpretation of in terms of local temperature. An observed asymmetry in the δ18O seasonal cycle may be explained by the precipitation of air masses coming from Indian and Pacific/West Antarctic Ice Sheet sectors in autumn and winter times, recorded in the d-excess signal showing outstanding values in austral spring versus autumn. Significant positive trends are observed in the annual d-excess record and local sea-ice extent (135°E–145°E) over the period 1998–2014.
However, processes studies focusing on resulting isotopic compositions and particularly the d-excess-δ18O relationship, evidenced as a potential fingerprint of moisture origins, as well as the collection of more isotopic measurements in Adélie Land are needed for an accurate interpretation of our signals.
Jourdain, Bruno; Legrand, Michel (2002): Year-round records of bulk and size-segregated aerosol composition and HCl and HNO₃ levels in the Dumont d'Urville (coastal Antarctica) atmosphere: Implications for sea-salt aerosol fractionation in the winter and summer. Journal of Geophysical Research, 107(D22), 4645, https://doi.org/10.1029/2002JD002471
Latitude: -66.780000 * Longitude: 139.560000
Minimum DEPTH, ice/snow: 0.0002 m * Maximum DEPTH, ice/snow: 0.1321 m
The TA192A core is a 21.3 m firn core drilled in 2015 at a coastal Antarctic high accumulation site in Adélie Land (66.78 °S; 139.56 °E, 602 m a.s.l.). Chemical elements, i.e. sulfate and methane sulfonic acid , as well as water stable isotope (δ18O and deutérium excess) were analysed at a 4 cm snow equivalent resolution. Non-sea-salt summer and winter sulfate were computed based on Jourdain et Legrand (2002). Records are given in function of firn core depth (in cm w.e.), and time.
|#||Name||Short Name||Unit||Principal Investigator||Method/Device||Comment|
|1||Number||No||Goursaud, Sentia||Number of sampling|
|2||DEPTH, ice/snow||Depth ice/snow||m||Goursaud, Sentia||Geocode – In meters water equivalent (w.e)|
|3||Age||Age||a AD/CE||Goursaud, Sentia|
|5||Original value||Orig val||Goursaud, Sentia||Methane sulfonic acid (ppb)|
|6||Methane sulfonic acid||MSA||µg/kg||Goursaud, Sentia|
|7||Sulfate||[SO4]2-||mg/kg||Goursaud, Sentia||Non-sea-salt summer sulfate|
|8||Sulfate||[SO4]2-||mg/kg||Goursaud, Sentia||Non-sea-salt winter sulfate|
|10||Deuterium excess||d xs||‰||Goursaud, Sentia|
4772 data points