The SP19 chronology for the South Pole Ice Core – Part 2: gas chronology, Δage, and smoothing of atmospheric records
The SP19 chronology for the South Pole Ice Core – Part 2: gas chronology, Δage, and smoothing of atmospheric records
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DOI：
10.5194/cp-2020-71-supplement
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发表时间：
2020-06
影响因子：
4.3
通讯作者：
Jenna A. Epifanio;E. Brook;C. Buizert;J. Edwards;T. Sowers;Emma C. Kahle;J. Severinghaus;E. Steig;D. Winski;E. Osterberg;T. Fudge;M. Aydin;E. Hood;M. Kalk;K. Kreutz;D. Ferris;J. Kennedy
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作者：
Jenna A. Epifanio;E. Brook;C. Buizert;J. Edwards;T. Sowers;Emma C. Kahle;J. Severinghaus;E. Steig;D. Winski;E. Osterberg;T. Fudge;M. Aydin;E. Hood;M. Kalk;K. Kreutz;D. Ferris;J. Kennedy
抽象的。在南极钻取的新冰芯提供了54000年的古环境记录，包括过去大气的组成。本文描述了南极大气气体记录的SP19年表，并补充了以前的论文（Winski等人，2019年10月，《冰》第19卷。气体年代学是基于离散的甲烷（CH 4）记录，分辨率为20至190年。为了构建气体时间尺度，在大气中甲烷的突然变化在冰期和百年甲烷变化在全新世期间被用来同步南极气体记录与类似的数据从西南极冰盖分水岭冰芯。利用自动匹配算法对基于视觉优化的地层匹配进行了验证。南极冰芯恢复所有预期的变化CH 4基于以前的记录。气体在积雪中的传输导致大气气体记录的平滑，平滑函数谱宽范围为30 - 78年，等于气体年龄-冰河年龄差异的3%，或Δ年龄。新的气体年代学与Winski等人（2019）现有的冰河时代尺度相结合，允许通过整个记录独立重建气体时代-冰河时代差异，这将有助于测试积雪致密化模型。
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 CH4 during the glacial period and centennial CH4 variability 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 CH4 based 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.