@article{a6520d40a28146279528bbf8472e42f2,
title = "The SP19 chronology for the South Pole Ice Core - Part 2: Gas chronology, Δage, and smoothing of atmospheric records",
abstract = "A new ice core drilled at the South Pole provides a 54 000-year paleoenvironmental record including the composition of the past atmosphere. This paper describes the SP19 chronology for the South Pole atmospheric gas record and complements a previous paper (Winski et al., 2019) describing the SP19 ice chronology. The gas chronology is based on a discrete methane (CH4) record with 20- to 190-year resolution. To construct the gas timescale, abrupt changes in atmospheric CH4during the glacial period and centennial CH4variability during the Holocene were used to synchronize the South Pole gas record with analogous data from the West Antarctic Ice Sheet Divide ice core. Stratigraphic matching based on visual optimization was verified using an automated matching algorithm. The South Pole ice core recovers all expected changes in CH4based on previous records. Gas transport in the firn results in smoothing of the atmospheric gas record with a smoothing function spectral width that ranges from 30 to 78 years, equal to 3% of the gas-age-ice-age difference, or Δage. The new gas chronology, in combination with the existing ice age scale from Winski et al. (2019), allows a model-independent reconstruction of the gas-age-ice-age difference through the whole record, which will be useful for testing firn densification models.",
author = "Epifanio, {Jenna A.} and Brook, {Edward J.} and Christo Buizert and Edwards, {Jon S.} and Sowers, {Todd A.} and Kahle, {Emma C.} and Severinghaus, {Jeffrey P.} and Steig, {Eric J.} and Winski, {Dominic A.} and Osterberg, {Erich C.} and Fudge, {Tyler J.} and Murat Aydin and Ekaterina Hood and Michael Kalk and Kreutz, {Karl J.} and Ferris, {David G.} and Kennedy, {Joshua A.}",
note = "Funding Information: Financial support. This research has been supported by the National Science Foundation, Office of Polar Programs (grant nos. 1443464, 1804145, 1643722, 1443472, 1443336, 1143105, 1141839, 1443710, 1142517, 1443470, and 1443397). Funding Information: Acknowledgements. This work was funded through grants from the US National Science Foundation (Todd Sowers (1443464 and 1804145), Edward Brook (1643722), Christo Buizert (1443472), Erich Osterberg (1443336), Eric Steig (1143105 and 1141839), Jeffrey Severinghaus (1443710), Murat Aydin (1142517 and 1443470), and Karl Kreutz (1443397)). We would like to thank Mark Twickler and Joe Souney with the SPC14 Science Coordination Office for their work administering the project; the U.S Ice Drilling Program for collecting the SPC14; the 109th New York Air National Guard for the airlift to and from Antarctica; the field team who collected the ice core; the members of South Pole and McMurdo stations who facilitated field operations; the National Ice Core Facility for ice core processing and storage; Ross Beaudette for his work lab work on gas datasets; and the many student researchers who produced data for the SP19 chronologies and helped to process the core. Publisher Copyright: {\textcopyright} 2020 BMJ Publishing Group. All rights reserved.",
year = "2020",
month = dec,
day = "3",
doi = "10.5194/cp-16-2431-2020",
language = "English (US)",
volume = "16",
pages = "2431--2444",
journal = "Climate of the Past",
issn = "1814-9324",
publisher = "European Geosciences Union",
number = "6",
}