RB-08-03 PNE 2008 Readme File Ship: NOAA research vessel Ronald H. Brown Cruise Start: Montevideo, Uruguay, April 29, 2008 Cruise End: Charleston, SC, May 18, 2008 Chief Scientists: Claudia Schmid (AOML) System Operator: Jonathan Shannahoff Expocode: 33RO20080429 Method: The system was built by General Oceanics (GO) and is described in Pierrot, et al. (2009). The three standard gases come from CMDL in Boulder and are directly traceable to the WMO scale. Sampling Cycle: The system runs on an cycle during which 4 standard gases, 5 air samples from the bow tower and 50 surface water samples (from the equilibrator head space) are analyzed on the following schedule: 1. Zero and span of Licor 2. Four standard gases 3. Five air samples 4. Fifty equilibrator headspace gas samples 5. Repeat steps 2 - 4 nine more times 6. Restart from step 1 Standards: CA06709: 284.75 ppm, CA02813: 363.24 ppm, CA09721: 423.57 ppm, CA07931: 545.88 ppm. 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. Salinity readings from the ship's TSG were bad. Readings from the Seabird Micro TSG in the Hydro Lab sink were used instead. This was connected to the old pCO2 analytical system which was running concurrently with the new system and thus was recorded at lower frequency than either the data from the ship's computer system (SCS) or the new GO system (1 every 4 - 4-1/2 minutes vs. 1 per minute for SCS and ~ 1 every 2-1/2 minutes for the GO system). The Micro TSG data were first merged into the data from the ship's computer system (SCS) with a 4-minute offset to account for the time it took seawater to travel from the bow intake to the Hydro Lab. This left numerous gaps in the SCS data file which contains 1-minute averages. Missing values in the Micro TSG data were interpolated. The Micro TSG data was then merged into the GO system data. 2. The system was shut down on May 7 from 00:25 to 20:33. It was also stopped on May 12 from 22:19 to 22:49. 3. An offset of -4.31 minutes was applied to SST data from the ship's computer system. This represents a compromise as the data appears to have a 0 offset at the beginning of the cruise and an offset of ~8 minutes at the end. 4. January 2017 made minor format changes to the header, added expocode and changed missing value to -999. Data was not altered. For questions or comments contact: Bob Castle 4301 Rickenbacker Causeway Miami, FL 33149 305-361-4418 robert.castle@noaa.gov Pierrot, D., C. Neil, K. Sullivan, R. Castle, R. Wanninkhof, H. Lueger, T. Johannson, A. Olsen, R. A. Feely, and C. E. Cosca (2009), Recommendations for autonomous underway pCO2 measuring systems and data reduction routines, Deep-Sea Res II, 56, 512-522.