Decadal Variation of the Surface Water PCO2 in the Western and Central Equatorial Pacific
Taro Takahashi,1*
Stewart C. Sutherland,1
Richard A. Feely,2
Catherine E. Cosca2
The equatorial Pacific Ocean is one of the most important yet
highly variable oceanic source areas for atmospheric carbon
dioxide (CO
2). Here, we used the partial pressure of CO
2 (
PCO
2),
measured in surface waters from 1979 through early 2001, to
examine the effect on the equatorial Pacific CO
2 chemistry of
the Pacific Decadal Oscillation phase shift, which occurred
around 1988 to 1992. During the decade before the shift, the
surface water
PCO
2 (corrected for temperature changes and atmospheric
CO
2 uptake) in the central and western equatorial Pacific decreased
at a mean rate of about –20 µatm per decade, whereas
after the shift, it increased at about +15 µatm per decade.
These changes altered the CO
2 sink and source flux of the equatorial
Pacific significantly.
2 Pacific Marine Environmental Laboratory (PMEL), National Oceanic and Atmospheric Administration (NOAA), Seattle, WA 98115, USA.
* To whom correspondence should be addressed. E-mail: taka{at}ldeo.columbia.edu
