Precise and continuous measurement of atmospheric CH 4 concentration was initiated at Syowa Station in February 1988. A diurnal variation of CH 4 concentration was not observable throughout the year, but irregular variations with periods of a few days and an amplitude of about 5 ppbv at most were sometimes observed. A regular seasonal cycle of CH 4 concentration with a winter maximum and a summer minimum was clearly seen. The peak-to-peak amplitude of the averaged seasonal cycle was 30 ppbv. CH 4 concentration was secularly increasing; the mean rate of the increase between 1988 and 1992 was 10.4 ppbv yr -1.
|出版ステータス||Published - 1997 12 1|
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