Earth System Science Data Discussions www.earth-syst-sci-data-discuss.net 1866-3591 2 1 2009 10.5194/essdd-2-63-2009 http://www.earth-syst-sci-data-discuss.net/2/63/2009/ http://www.earth-syst-sci-data-discuss.net/2/63/2009/essdd-2-63-2009.html http://www.earth-syst-sci-data-discuss.net/2/63/2009/essdd-2-63-2009.pdf 63 101 2009-07-17 CARINA: nutrient data in the Atlantic Ocean T. Tanhua ttanhua@ifm-geomar.de P. J. Brown R. M. Key Leibniz-Institut für Meereswissenschaften, Marine Biogeochemie, Kiel, Germany School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK Atmospheric and Oceanic Sciences Program, Princeton Univ., Princeton, NJ 08544, USA Data on carbon and carbon-relevant hydrographic and hydrochemical parameters from previously non-publicly available cruise data sets in the Arctic, Atlantic and Southern Ocean have been retrieved and merged to a new database: CARINA (CARbon IN the Atlantic). These data have gone through rigorous quality control (QC) procedures to assure the highest possible quality and consistency. The data for most of the measured parameters in the CARINA data base were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the data products, i.e. three merged data files with measured, calculated and interpolated data for each of the three CARINA regions; Arctic, Atlantic and Southern Ocean. Out of a total of 188 cruise entries in the CARINA database, 98 were conducted in the Atlantic Ocean and of these 84 cruises report nitrate values, 79 silicate, and 78 phosphate. Here we present details of the secondary QC for nutrients for the Atlantic Ocean part of CARINA. Procedures of quality control, including crossover analysis between cruises and inversion analysis of all crossover data are briefly described. Adjustments were applied to the nutrient values for 43 of the cruises in the Atlantic Ocean region. With these adjustments the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s (Key et al., 2004). Based on our analysis we estimate the internal accuracy of the CARINA-ATL nutrient data to be: nitrate 1.5%; phosphate 2.6%; silicate 3.1%. The CARINA data are now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation. Gouretski, V. V. and Jancke, K.: Systematic errors as the cause for an apparent deep water property variability: global analysis of the WOCE and historical hydrographic data, Prog. Oceanogr., 48, 337–402, 2001. Key, R. M., Kozyr, A., Sabine, C. L., Lee, K., Wanninkhof, R., Bullister, J. L., Feely, R. A., Millero, F. J., Mordy, C., and Peng, T. H.: A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP), Global Biogeochem. Cy., 18, GB4031, doi:1029/2004GB002247, 2004. Key, R. M., Tanhua, T., Olsen, A., Hoppema, M., Jutterström, S., Schirnick, C., van Heuven, S., Lin, X., Wallace, D. W. R., and Mintrop, L.: The CARINA data synthesis project: Introduction and overview, Earth Syst. Sci. Data Discuss., in preparation, 2009. Tanhua, T., Steinfeldt, R., Key, R. M., Brown, P., Gruber, N., Wanninkhof, R., Perez, F., Körtzinger, A., Velo, A., Schuster, U., van Heuven, S., Talley, L., Bullister, J. L., Stendardo, I., Hoppema, M., Olsen, A., Kozyr, A., Pierrot, D., Schirnick, C., and Wallace, D. W. R.: Overview of the Atlantic Ocean CARINA data and salinity measurements, Earth Syst. Sci. Data Discuss., submitted, 2009a. Tanhua, T., van Heuven, S., Key, R. M., Velo, A., Olsen, A., and Schirnick, C.: Quality control procedures and methods of the CARINA database, Earth Syst. Sci. Data Discuss., submitted, 2009b.