HB1103 ReadMe Class of Data: Surface ocean carbon dioxide concentrations Dataset Identifier: HB1103-Legs 1-3 Sea Turtle and Seabird Survey Expocode: 33HH20110604 Statement of how to cite dataset: Bigelow website: http://www.aoml.noaa.gov/ocd/gcc/rvbigelow_introduction.php For more information on dataset citation please see Master Readme File. Measurement platform identifier: NOAA Ship Henry B. Bigelow, R225 Time period the dataset refers to: 4 June, 2011 - 24 July, 2011 Geographic area the dataset refers to: Latitude, 36.5 to 41.5 degree north Longitude, 66.0 to 74.9 degree west Standard and Reference Gases: The four CO2 standard cylinders come from Scott-Marrin, Inc., and are calibrated with primary standards that are directly traceable to the WMO scale. The zero gas is ultra-high purity air. Any value outside the range of the standards should be considered approximate (+/-5 ppm). While individual data points above 520 or below 200 may less accurate, the general trends would be indicative of the seawater chemistry. The standards used on the cruise are: STANDARD TANK # [CO2]ppm VENDOR STD1 JA02645 204.74 Scott-Marrin STD2 JA02273 317.49 Scott-Marrin STD3 JA02285 372.23 Scott-Marrin STD4 JA02647 518.24 Scott-Marrin STD5 JA03093 0.00 Scott-Marrin Data quality issues: The SCS feed of real-time data from the ship's sensors was accidently turned off early during leg1 of the cruise. After the cruise, a file of one-minute averages of sea surface temperature (SST), salinity, and barometric pressure was merged with the CO2 data. Barometric pressure was not recorded between 21:00 on 6 June and 00:30 on 7 June. For the 76 CO2 analyses during that interval, the barometric pressure was estimated by adding 0.12 to the LICOR pressure. For the 50 analyses before and after the gap, the average difference between the barometric pressure and the Licor pressure was 0.12 (+/- 0.09) mbar. After leg1, the ship's data was being recorded as 15-second averages. For leg2 of this cruise, the 15-second averages were used to fill gaps in the data appended to the CO2 data in real-time (i.e. 665 barometric pressures, 537 sea surface temperatures, 472 salinities). For leg3 of this cruise, the 15-second averages were used to fill gaps in the data appended to the CO2 data in real-time (i.e. 224 barometric pressures, 192 sea surface temperatures, 189 salinities). The GPS signal to the CO2 analytical system was lost near 18:00 on 4 June. The ship's location in the one-minute average file was merged with these ~5300 CO2 data records for the last 10 days of leg1. The GPS signal to the CO2 analytical system was lost between 18:00 on 4 July and 20:00 on 5 July. The ship's location in the 15-second average file was merged with these 613 CO2 data records of leg2. The sea water flow during leg1 of this cruise was better than during HB1102, but still not optimal. For most of leg1, the sea water flow was between 0.8 amd 1.2 liters/minute, which is acceptable. For the first 1.5 days and short intervals during leg1, the sea water flow was between 0.3 and 0.5 L/min which is barely acceptable. Between leg1 and leg2, the sea water connection for the CO2 analytical system was moved from after the debubbler to before the debubbler. Also, the operational settings of valves controlling the seawater pressure were adjusted to increase the flow through the analytical system. During leg2 and leg3 the seawater flow remained between 1.8 and 2.3 L/min, which is optimal. Timestamp for dataset reduction: 27 October, 2011 Timestamp for most recent update of dataset: 27 October, 2011 Matlab version used for reduction: 1.10 Contact person for this dataset: Kevin Sullivan (305)361-4382 Kevin.Sullivan@noaa.gov