Source and Scope of the Data

This package documents carbonate data obtained during two NOAA CO₂ Dynamics Cruises and the NORPAX Hawaii-Tahiti Shuttle Experiment. The contributors participated in the two former cruises and obtained data from samples collected during the NORPAX Hawaii-Tahiti Shuttle Experiment. Table 1. provides a summary of the data available from each of the cruises.

One data source was NOAA's CO₂ Dynamics Cruise of the eastern North Pacific aboard the R/V MILLER FREEMAN. The ship departed Kodiak, Alaska on June 14, 1981 and arrived at Hilo, Hawaii on July 4th after occupying nine stations along the 150 °W vertical transect. After reaching the southernmost point of the cruise track (°N), the R/V MILLER FREEMAN occupied seven stations while returning to Seattle, Washington. Data, including alkalinity, calcium, and pH, are provided for all sixteen stations.

Alkalinity was determined using the method of Culberson et al., (1970) at 25 ± 0.02°C. Calcium samples were stored and brought back to Oregon State University where determinations were made using the methods of Tsunogai et al., (1968) and Olson and Chen (1981). Measurements for pH were done at 25 ± 0.02°C using a combination electrode.

The second source of the data, NOAA's CO₂Dynamics cruise in the western North Pacific aboard R/V DISCOVERER, departed Kwajalein, Alaska on May 27, 1982 and arrived at Adak, Alaska on June 29, 1982. During the cruise, ten stations were occupied with all stations located near the 165°E vertical transect. Total alkalinity and pH measurements were determined at 25 ± 0.02°C using a Radiometer TTT61 Digital Titrator and a combination electrode, respectively.

For the NORPAX Hawaii-Tahiti Shuttle Experiment, samples were collected during Legs 3 (April, 1979) and 13 (March-April, 1980). Alkalinity was determined using the method of Culberson et al., (1970), calcium measured using the methods of Tsunogai et al., (1968) and Olson and Chen (1981), and salinities were determined using an Autosal inductive salinometer.

Based on these data, Chen et al., (1986) concluded that the North Pacific Ocean contains 14.7 ± 4 X 10¹⁵ g excess carbon and that the deep water of the eastern North Pacific is older than that of the western North Pacific. They also estimated that about a 25% increase in total inorganic CO₂ of deep water, after leaving the Southern Ocean surface, is contributed by inorganic CaCO₃ dissolution.

Greater details about the cruise tracks, the precision and calibration of the experimental techniques, and the findings resulting from the cruises of the North Pacific Ocean are discussed in the pertinent literature (Chen et al., 1986) provided in the printed version of this document.