JMA's Observations

   JMA has observed surface concentrations of CO₂ at three stations in Japan.
   The upper panel of the following figures shows a time series graph of CO₂ concentrations at the three stations. At all stations, CO₂ concentrations increase with seasonal variation in relation to photosynthesis and respiration in the biosphere. The CO₂ concentration at Ryori has a larger seasonal variation than the other two stations because of its location at a high latitude, where the atmosphere is significantly influenced by biospheric activity. The CO₂ concentrations are generally higher at Yonagunijima than at Minamitorishima despite the almost identical latitudes of the two locations. This reflects the influence of anthropogenic and wintertime biospheric emissions from the Asian continent.
   Growth rates of CO₂ concentrations at the three stations increase and decrease almost simultaneously, as shown in the lower panel of the following figures. Remarkably high growth rates from 1997 to 1998 and from 2002 to 2003 are related to the El Niño events of 1997/1998 and 2002/2003, respectively. The high growth rates during 2005-2006, during a La Niña event rather than an El Niño event, may be related to increased CO₂ emissions from fossil fuel combustion and the global high temperature, with the high hemispheric mean temperature in the Northern Hemisphere. The latest El Niño event has occurred in 2009/2010. Corresponding variations in CO₂ growth rates were observed in global mean concentrations.

Time series of CO₂ concentrations and growth rates observed at JMA's observatories

Zonally averaged CO₂ concentrations

   The follwing figure shows variations in zonally averaged atmospheric CO₂ concentrations produced by the WDCGG using archived data from all over the world. The concentrations are high in mid and high latitudes in the Northern Hemisphere, and decrease toward the southerly latitudes. This latitudinal distribution of CO₂ concentration is ascribed to the existence of major CO₂ sources in the mid and high latitudes of the Northern Hemisphere. The seasonal variation (a decrease from spring to summer and an increase from summer to the following spring) is mainly due to the activity of the terrestrial biosphere, and the amplitude is smaller in the Southern Hemisphere because of the small land area. In both hemispheres, atmospheric CO₂ concentrations are increasing year by year.

Time series of zonally averaged CO₂ concentrations

CO₂ distribution

   JMA analyzes global CO₂ distributions. The results are shown in the other pages. The URL of top page for CO₂ distribution is http://ds.data.jma.go.jp/ghg/kanshi/info_kanshi_e.html.

Japan Meteorological Agency, 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan
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