Topics 2015.06.26

Greenhouse gases observation in the Arctic region

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Greenhouse gases such as carbon dioxide (CO2), methane (CH4), etc. have increased in the atmosphere by human activities, and then, global warming and climate change are being concerned.ツ黴€ To address this problem, it is necessary to clarify the current budget of the greenhouse gases on the earth's surface and to understand its response with respect to the climate and environmental changes.ツ黴€ Since there are important sources and sinks of the greenhouse gases in the Arctic region (e.g. boreal forest, wetland, permafrost and the Arctic Ocean) and the most significant warming is predicted there, it is pointed out the emission of the greenhouse gases would be enhanced from natural sources and/or CO2 exchange rates would change between terrestrial biosphere and atmosphere.ツ黴€ However, the observation in the Arctic region is still limited until now, because access to the Arctic region has been difficult.

In recent years, interest to the environment change in the Arctic increased and also the need to promote Arctic research in Japan has been recognized.ツ黴€ In 2011, a new Japanese initiative 'Arctic Climate Change Research Project' has been initiated within the framework of GRENE (Green Network of Excellence) program funded by the Ministry of Education, Culture, Sports, Science and Technology.ツ黴€ Our laboratory is promoting a wide range of observation and research as a coordinator of the research group on 'Greenhouse gases in the Arctic' in the GRENE project.ツ黴€ This research group consists of over 30 scientists from 12 research institutes and universities (Tohoku Univ., NIPR, Nagoya Univ., Hokkaido Univ., Miyagi Univ. of Education, Tokyo Institute of Technology, National Institute of Environment Study, National Institute of Advanced Industrial Science and Technology (AIST), Meteorological Research Institute, Japan Agency for Marine-Earth Science and Technology and RIKEN).ツ黴€ The members have conducted observations of the Arctic atmosphere and ocean, ice core analyses and numerical simulations with atmospheric-chemistry transport models.

Figure shows our pan-Arctic observation network for greenhouse gases.ツ黴€ At the ground base sites, Ny-Alesund (79°N, 15°E), Churchill (59°N, 94°W) and Rishiri Island and so on, we have carried out the time-series observations of the greenhouse gases and related constituents' concentrations and their isotope ratios with grab-sampling method as well as in-situ continuous measurements.ツ黴€ Tropospheric and lower stratospheric observations over the Eurasian continent have been conducted by using commercial aircraft flying between Japan and France/Russia, and maritime air and oceanic observation have been performed in Chukchi Sea with R/V MIRAI cruise.ツ黴€ To reveal temporal variations of major greenhouse gases in the past, ice core samples and firn air samples obtained in the Greenland have been analyzed.ツ黴€ In addition, sources and sinks of the greenhouse gases in the Arctic region have been evaluated by the modelers with state-of-art atmospheric-chemistry transport models.

A part of the observations conducted by Tohoku Univ. in the Arctic region is as follows.

Ny-Alesund is one of the suitable sites for the observation of Arctic background air, since there is almost no source in the vicinity.ツ黴€ We have maintained systematic air sampling at the Ny-Alesund observatory of NIPR and subsequent analyses for the greenhouse gases concentrations (CO2, CH4, nitrous oxide (N2O), hexafluoride (SF6)), isotope ratios (CO2 and CH4) and related constituents (CO and O2/N2 raio) in our lab.ツ黴€ In addition, in-situ continuous observations for concentrations of CO2, CH4, CO and O2/N2 ratio also started in Ny-Alesund in collaboration with NIPR and AIST.

Churchill, facing the Hudson Bay, is surrounded by wetland and forest where a large amount of organic matter, raw material of CO2 and CH4, is contained in the soil.ツ黴€ Meteorological Service of Canada has maintained systematic observations of the greenhouse gases in Churchill and we have been responsible for the carbon and hydrogen isotope measurements for CH4.

The GRENE program will be completed in this fiscal year.ツ黴€ Towards perfection of the research project, data analyses and model simulations are proceeding.


(Prof. Morimoto, Trace gase Research Group Center for Atmospheric and Oceanic Studies)

Link: Trace Gas Research Group Center for Atmospheric and Oceanic Studies

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(1:Ny-Alesund, 2: Churchill, 3: Our pan-Arctic observation network.)

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