TY - JOUR
T1 - Long-term variations of the mole fraction and carbon isotope ratio of atmospheric methane observed at Ny-Ålesund, Svalbard from 1996 to 2013
AU - Morimoto, Shinji
AU - Fujita, Ryo
AU - Aoki, Shuji
AU - Goto, Daisuke
AU - Nakazawa, Takakiyo
N1 - Funding Information:
This work was partly supported by the JSPS KAKENHI grant numbers 23310012 and 15H03722; ‘Green Network of Excellence’ (Arctic Project ID 5) and ‘Arctic Challenge of Sustainability’ ID 3 from the Ministry of Education, Culture, Sports, Science and Technology, Japan, and cooperative project KP-15 from the National Institute of Polar Research, Japan.
Publisher Copyright:
© 2017, © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - We have conducted systematic observations of the CH4 mole fraction and its carbon isotope ratio (δ13C) at Ny-Ålesund, Svalbard (78°55′N, 11°56′E) using air samples collected weekly since 1991 and 1996, respectively. The CH4 mole fraction showed long-term increase until 1999, stagnation between 2000 and 2006, followed by an increase after 2006. On the other hand, δ13C showed monotonous increase until 2006 and decrease after 2006. By comparing the rates of change in the CH4 mole fraction and δ13C under the assumption that the atmospheric CH4 lifetime is constant, it is suggested that the temporal pause of the CH4 mole fraction observed at Ny-Ålesund is attributed to reductions of CH4 release from the microbial and fossil fuel sectors. On the other hand, the increase in CH4 after 2006 could be ascribed to an increase in microbial CH4 release. The CH4 and δ13C data presented in this paper would be useful for clarifying their temporal variations in the Arctic atmosphere, as well as providing additional constraints on the global CH4 budget.
AB - We have conducted systematic observations of the CH4 mole fraction and its carbon isotope ratio (δ13C) at Ny-Ålesund, Svalbard (78°55′N, 11°56′E) using air samples collected weekly since 1991 and 1996, respectively. The CH4 mole fraction showed long-term increase until 1999, stagnation between 2000 and 2006, followed by an increase after 2006. On the other hand, δ13C showed monotonous increase until 2006 and decrease after 2006. By comparing the rates of change in the CH4 mole fraction and δ13C under the assumption that the atmospheric CH4 lifetime is constant, it is suggested that the temporal pause of the CH4 mole fraction observed at Ny-Ålesund is attributed to reductions of CH4 release from the microbial and fossil fuel sectors. On the other hand, the increase in CH4 after 2006 could be ascribed to an increase in microbial CH4 release. The CH4 and δ13C data presented in this paper would be useful for clarifying their temporal variations in the Arctic atmosphere, as well as providing additional constraints on the global CH4 budget.
KW - Arctic
KW - atmospheric methane
KW - greenhouse gas
KW - stable carbon isotope
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U2 - 10.1080/16000889.2017.1380497
DO - 10.1080/16000889.2017.1380497
M3 - Article
AN - SCOPUS:85042860938
VL - 69
JO - Tellus, Series B: Chemical and Physical Meteorology
JF - Tellus, Series B: Chemical and Physical Meteorology
SN - 0280-6509
IS - 1
M1 - 1380497
ER -