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Ice‐core record of methyl chloride over the last glacial–Holocene climate change
Author(s) -
Saito Takuya,
Yokouchi Yoko,
Aoki Shuji,
Nakazawa Takakiyo,
Fujii Yoshiyuki,
Watanabe Okitsugu
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl028090
Subject(s) - glacial period , holocene , ice core , interglacial , geology , ice sheet , last glacial maximum , climate change , physical geography , climatology , oceanography , geomorphology , geography
Methyl chloride (CH 3 Cl) concentration was measured in air trapped in a deep ice core from Dome Fuji, Antarctica covering the last glacial–present interglacial (Holocene) change. The record shows that the CH 3 Cl concentration was relatively constant, being similar to the present levels, during the pre‐industrial Holocene. In contrast, the CH 3 Cl concentration was significantly high and variable in the last glacial period, possibly due to impurity‐related production of CH 3 Cl in ice sheet. Under the assumption that the production was the sole cause of the excess CH 3 Cl, the atmospheric CH 3 Cl concentration during the last glacial was estimated using simultaneously measured calcium data for the ice core to have been enhanced by 30% compared with the pre‐industrial Holocene concentration. Because the major sink of CH 3 Cl was stronger during the last glacial than during the Holocene, the enhancement of CH 3 Cl during the last glacial was likely due to the glacial period source being enhanced.