Interannual variation of growth rate of atmospheric carbon dioxide concentration observed at the JMA's three monitoring stations: Large increase in concentration of atmospheric carbon dioxide in 1998

The Japan Meteorological Agency has been monitoring carbon dioxide (CO2) concentrations in the atmosphere continuously with non-dispersive infrared gas analyzers since January 1987 at Ryori, March 1993 at Minamitorishima, and January 1997 at Yonagunijima. At Ryori with our longest record, a large variation was found in CO2 growth rate in association with significant global events such as El Nino and the eruption of Mt. Pinatubo, suggesting that global changes in the carbon cycle are closely connected with the climate. The annual growth rates in CO2 concentration were 3.0 ppm at Ryori, 2.8 ppm at Minamitorishima, and 3.1 ppm at Yonagunijima in 1998. At Ryori and Minamitorishima, they were the largest since the beginning of measurement. It is supposed that this large growth rate is attributed to the strong El Nino event in 1997/98.