Comparison of the Carbon System Parameters at the Global CO₂ Survey Crossover Locations in the North and South Pacific Ocean, 1990-1996

Feely, Richard A., Marilyn F. Lamb, Dana J. Greeley, NOAA, Pacific Marine Environmental Laboratory, Seattle, Washington; and Rik Wanninkhof, NOAA, Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida

Prepared by Linda Allison and Dana Griffith, CDIAC

ORNL/CDIAC-115 (1999) (http://cdiac.esd.ornl.gov/oceans/pmel/pmel.html)

As part of a collaborative program to measure global ocean carbon inventories and provide estimates of the anthropogenic CO₂ uptake by the oceans, NOAA and DOE cosponsored the collection of ocean carbon measurements via the U.S. Joint Global Ocean Flux Study (JGOFS) Program. Investigators supported by these funding agencies collaborated to examine data collected during the World Ocean Circulation Experiment (WOCE) and Ocean-Atmosphere Carbon Exchange Study (OACES) cruises.

The Pacific Ocean cruises in this report occurred from 1990 through 1996 and overlapped in the North and South Pacific Ocean. Four parameters of the oceanic CO₂ system from 30 crossover locations were compared to ensure that a consistent global data set emerged from the survey cruises. These parameters included dissolved inorganic carbon (DIC), fugacity of CO₂ (fCO₂), total alkalinity (TALK), and pH, along with salinity and dissolved oxygen (O₂).

The world's oceans, widely recognized to be the major long-term control on the rate of CO₂ increases in the atmosphere, are believed to be absorbing about 2.0 GtC yr^-1 (nearly 30 to 40% of the annual release from fossil fuels). Our present understanding of oceanic sources and sinks for CO₂ is derived from a combination of field data that are limited by sparse temporal and spatial coverage and model results that are validated by comparisons with oceanic bomb ¹⁴C profiles.