Concentration variations of atmospheric CO2 observed at Syowa Station, Antarctica from 1984 to 2000

Shinji Morimoto, Takakiyo Nakazawa, Shuji Aoki, Gen Hashida, Takashi Yamanouchi

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Systematic and continuous measurements of the atmospheric CO2 concentration have been carried out at Syowa Station, Antarctica since February 1984. The measurement system was renewed in 1995, but the continuity of the data from the two systems was confirmed by operating them simultaneously. The CO2 data taken for 17 years from 1984 to 2000 showed clear evidence for a seasonal cycle, a secular trend and interannual variations. The seasonal cycle was variable from year to year, with especially larger amplitudes in 1992 and 1998 and a large phase delay in 1993. A rapid increase in the CO2 concentration was observed in 1987, 1994 and 1998 in association with ENSO events. The average rate of the secular CO2 increase for the last 17 years was calculated to be 1.49 ppmv yr-1. Short-term CO2 variations with amplitudes of around 1.0 ppmv were found in the austral summer season of several years after 1990, probably due to an intrusion of CO2-depleted air mass into the Antarctic region.

Original languageEnglish
Pages (from-to)170-177
Number of pages8
JournalTellus, Series B: Chemical and Physical Meteorology
Issue number2
Publication statusPublished - 2003 Apr
Externally publishedYes

ASJC Scopus subject areas

  • Atmospheric Science


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