HB1206 ReadMe Class of Data: Surface ocean carbon dioxide concentrations Dataset Identifier: HB1206-Legs 1-4 Autumn Bottom Trawl Survey Expocode: 33HH20120907 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: 7 Sept, 2012 - 11 Nov, 2012 Geographic area the dataset refers to: Latitude, 34.3 to 44.4 degree north Longitude, 65.7 to 76.4 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 analytical system operated well throughout this cruise. During leg three, the reading from the ship's barometer was not available for approximately one hour starting at 15:15 on 19 October. The outside barometric pressure for this interval was estimated by subtracting 1.14 mbar from LICOR pressure. This offset, 1.14 (+/- 0.18) mbar, was calculated from the 100 data records before and after the gap. During leg four, the sea water flow reaching the TSG and CO2 instruments in the dry lab was very low for approximately thirty hours starting at 13:30 on 3 November. Only outside air analyses are reported for this interval. For the majority of the four legs of this cruise, the water flow through the pCO2 instrument was generous (1.6 - 2.1 L/min). For two days during leg four starting at 12:00 on 7 November, the ship sought protection from a severe storm. In the relative calm of Cape Cod Bay, the flowing sea water system was secured and the CO2 data acquisition was interrupted. The cruise was completed with no additional disruptions. Timestamp for dataset reduction: 27 Nov, 2012 Timestamp for most recent update of dataset: 27 Nov, 2012 Matlab version used for reduction: 1.10 Contact person for this dataset: Kevin Sullivan (305)361-4382 Kevin.Sullivan@noaa.gov