RB-05-03SB Sea Beam Patch Testing Cruise Readme File Ship: NOAA research vessel Ronald H. Brown Cruise Start: Charleston, S.C., July 12, 2005 Cruise End: Woods Hole, MA, July 15, 2005 Chief Scientist: Jonathan Shannahoff System Operator: Jonathan Shannahoff Expocode: 33RO20050712 Method: Infrared absorption of dried gas. For details of the system see: Measurement of fugacity of Carbon Dioxide in surface water and air using continuous sampling methods. Wanninkhof and Thoning, 1993 in Marine Chemistry 44, 189-205, And: Feely, R.A., R. Wanninkhof, H.B. Milburn, C.E. Cosca, M. Stapp, and P.P. Murphy, A new automated underway system for making high precision pCO2 measurements onboard research ships, Analytica Chim. Acta, 377, 185-191, 1998. The three standard gases come from CMDL in Boulder and are directly traceable to the WMO scale. Sampling Cycle: The system runs on an hourly cycle during which 3 standard gases, 3 air samples from the bow tower and 8 surface water samples (from the equilibrator head space) are analyzed on the following schedule: Mins. after hour Sample 4 Low Standard 8 Mid Standard 12 High Standard 16.5 Water 21 Water 25.5 Water 30 Water 34 Air 38 Air 42 Air 46.5 Water 51 Water 55.5 Water 60 Water Units: All xCO2 values are reported in parts per million (ppm) and fCO2 values are reported in microatmospheres (uatm) assuming 100 % humidity at the equilibrator temperature. Notes: 1. Any values outside the range of the standards (303.23, 370.9, & 411.42 ppm) should be considered approximate (within 5 ppm). While individual data points above 411 or below 303 may not be accurate, the general trends should be indicative of the seawater chemistry. 2. There was no water flow from the beginning of the cruise until July 12 at 1230. All water values were removed through July 12 at 1330. For questions or comments contact: Bob Castle 4301 Rickenbacker Causeway Miami, FL 33149 305-361-4418 robert.castle@noaa.gov