Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 6 10 2009 10.5194/bg-6-1961-2009 http://www.biogeosciences.net/6/1961/2009/ http://www.biogeosciences.net/6/1961/2009/bg-6-1961-2009.html http://www.biogeosciences.net/6/1961/2009/bg-6-1961-2009.pdf 1961 1974 2009-10-02 Statistical validation of a 3-D bio-physical model of the western North Atlantic M. K. Lehmann K. Fennel katja.fennel@dal.ca R. He Department of Oceanography, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia B3H 4J1, Canada Department of Marine, Earth and Atmosphere Sciences, North Carolina State University, Raleigh, NC 27695, USA High-resolution, physical-biological models of coastal and shelf regions typically use a single functional phytoplankton group, which limits their ability to represent ecological gradients (e.g. highly productive shelf systems adjacent to oligotrophic regions), as these are dominated by different functional phytoplankton groups. We implemented a size-structured ecosystem model in a high-resolution, regional circulation model of the northeast North American shelf and adjacent deep ocean in order to assess whether the added functional complexity of two functional phytoplankton groups improves the model's ability to represent surface chlorophyll concentrations along an ecological gradient encompassing five distinct regions. We used satellite-derived SST and sea-surface chlorophyll for our model assessment, as these allow investigation of spatial variability and temporal variations from monthly to interannual, and analyzed three complimentary statistical measures of model-data agreement: model bias, root mean square error and model efficiency (or skill). All three measures were integrated for the whole domain, for distinct subregions and were calculated in a spatially explicit manner. Comparison with a previously published simulation that used a model with a single phytoplankton functional group indicates that the inclusion of an additional phytoplankton group representing picoplankton markedly improves the model's skill. Allen,~J I., Somerfield,~P J., and Gilbert,~F J.: Quantifying uncertainty in high-resolution coupled hydrodynamic-ecosystem models, J Marine Syst., 64, 3–14, 2007. Armstrong,~R A.: Stable model structures for representing biogeochemical diversity and size spectra in plankton communities, J Plankton Res., 21, 445–464, 1999. Cai,~W., Wang,~Z., and Wang,~Y.: The role of marsh-dominated heterotrophic continental margins in transport of \chemCO_2 between the atmosphere, the land-sea interface and the ocean, Geophys. Res. Lett., 30, 1848, doi:10.1029/2003GL017633, 2003. Chapman,~D. and Beardsley,~R.: On the origin of shelf water in the Middle Atlantic Bight, J Phys. Oceanogr., 19, 384–391, 1989. Chassignet,~E P., Hurlburt,~H E., Smedstad,~O M., Halliwell,~G R., Hogan,~P J., Wallcraft,~A J., Baraille,~R., and Bleck,~R.: The HYCOM (HYbrid Coordinate Ocean Model) data assimilative system, J Marine Syst., 65, 60–83, 2007. Churchill,~J., Cornillon,~P., and Milkowski,~G.: A~cyclonic eddy and shelf-slope water exchange associated with a~Gulf Stream warm-core ring, J Geophys. Res., 91, 9615–9623, 1986. Coles, V. J. and Hood, R. R.: Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean, Biogeosciences, 4, 455–479, 2007. Cullen, J J., Franks,~P J S., Karl,~D M., Longhurst,~A.: Chapter 8: Physical influences on marine ecosystem dynamics, in: The Sea, edited by: Robinson, A. R., McCarthy, J. J., and Rothshild, B. J., John Wiley and Sons, New York, 12, 297–336, 2002. DuRand,~M D., Olson,~R J., Sallie W. Chisholm,~S W.: Phytoplankton population dynamics at the Bermuda Atlantic Time-series station in the Sargasso Sea, Deep Sea Res. II, 48, 1983–2003, 2001. Dutkiewicz,~S., Follows,~M., Marshall,~J., and Gregg,~W.: Interannual variability of phytoplankton abundances in the North Atlantic, Deep-Sea Res. Pt. II, 48, 2323–2344, 2001. Fasham,~M J R., Sarmiento,~J L., Slater,~R D., Ducklow,~H W., and Williams,~R.: Ecosystem behavior at Bermuda station \qutS and ocean weather station \qutIndia: A~general-circulation model and observational analysis, Global Biogeochem. Cy., 7, 379–415, 1993. Fennel,~K., Wilkin,~J., Levin,~J., Moisan,~J., O'Reilly,~J., and Haidvogel,~D.: Nitrogen cycling in the Middle Atlantic Bight: results from a~three-dimensional model and implications for the North Atlantic nitrogen budget, Global Biogeochem. Cy., 20, GB3007, doi:10.1029/2005GB002456, 2006. Fennel,~K., Wilkin,~J., Previdi,~M., and Najjar,~R.: Denitrification effects on air-sea \chemCO_2 flux in the coastal ocean: simulations for the northwest North Atlantic, Geophys. Res. Lett., 35, L24608, doi:10.1029/2008GL036147, 2008. Flather,~R A.: A~tidal model of the northwest European continental shelf, Mem. Soc. R. Sci. Liege, 10, 141–164, 1976. Franks,~P J S. and Chen,~C.: A~3-D prognostic numerical model study of the Georges bank ecosystem. Part II: biological-physical model, Deep-Sea Res. II, 48, 457–482, doi:10.1016/S0967-0645(00)00125-9, 2001. Friedrichs,~M., Dusenberry,~J., Anderson,~L., Armstrong,~R., Chai,~F., Christian,~J., Doney,~S., Dunne,~J., Fujii,~M., and Hood,~R.: Assessment of skill and portability in regional marine biogeochemical models: role of multiple planktonic groups, J Geophys. Res., 112, 8001, doi:10.1029/2006JC003852, 2007. Geider,~R., MacIntyre,~H., and Kana,~T.: A~dynamic regulatory model of phytoplanktonic acclimation to light, nutrients, and temperature, Limnol. Oceanogr., 43, 679–694, 1998. Greene,~C. and Pershing,~A.: Climate drives sea change, Science, 315, 1084–1085, 2007. Gruber,~N., Frenzel,~H., Doney,~S., Marchesiello,~P., McWilliams,~J., Moisan,~J., Oram,~J., Plattner,~G., and Stolzenbach,~K.: Eddy-resolving simulation of plankton ecosystem dynamics in the California current system, Deep-Sea Res. I, 53, 1483–1516, 2006. Haidvogel,~D B., Arango,~H., Budgell,~W P., Cornuelle,~B D., Curchitser,~E., Lorenzo,~E D., Fennel,~K., Geyer,~W R., Hermann,~A J., Lanerolle,~L., Levin,~J., McWilliams,~J C., Miller,~A J., Moore,~A M., Powell,~T M., Shchepetkin,~A F., Sherwood,~C R., Signell,~R P., Warner,~J C., and Wilkin,~J.: Ocean forecasting in terrain-following coordinates: formulation and skill assessment of the regional ocean modeling system, J Comput. Phys., 227, 3595–3624, doi:10.1016/j.jcp.2007.06.016. 2008. He,~R. and Chen,~K.: Investigation of northeastern North America coastal circulation using a~regional circulation hindcast model. Part 1: mean circulation, J Geophys. Res., submitted, 2009. Hofmann,~E., Druon,~J., Fennel,~K., Friedrichs,~M., Haidvogel,~D., Lee,~C., Mannino,~A., McClain,~C., Najjar,~R., O'Reilly,~J., Pollard,~D., Previdi,~M., Seitzinger,~S., Siewert,~S., Signorini,~S., and Wilkin,~W.: Eastern US continental shelf carbon budget: integrating models, data assimilation and analysis, Oceanography, 21, p 86, 2008. Houghton,~R., Flagg,~C., and Pietrafesa,~L.: Shelf-slope water frontal structure, motion and eddy heat flux in the southern Middle Atlantic Bight, Deep-Sea Res. II, 41, 273–306, 1994. Kilpatrick,~K A., Podesta,~G P., and Evans,~R.: Overview of the NOAA/NASA advanced very high resolution radiometer Pathfinder algorithm for sea surface temperature and associated matchup database, J Geophys. Res., 106(C5), 9179–9198, doi:10.1029/1999JC000065, 2001. Kiorboe,~T.: Turbulence, phytoplankton cell size and the structure of pelagic food webs, Adv. Mar. Biol., 29, 1–72, 1993. Li,~W K W., Harrison,~W G.: Chlorophyll, bacteria and picophytoplankton in ecological provinces of the North Atlantic, Deep Sea Res. II, 48, 2271–2293, 2001. Lima,~I D. and Doney,~S C.: A~three-dimensional, multinutrient, and size-structured ecosystem model for the North Atlantic, Global Biogeochem. Cy., 18, GB3019, doi:10.1029/2003GB002146, 2004. Linder,~C. and Gawarkiewicz,~G.: A~climatology of the shelfbreak front in the Middle Atlantic Bight, J Geophys. Res., 103, 18405–18423, 1998. Loder,~J W., Petrie,~B., and Gawarkiewicz,~G.: The coastal ocean off northeastern North America: a~large-scale view, in: The Sea, edited by: Robinson,~A R. and Brink,~K H., 11, 105–133, John Wiley and Sons, Inc., New York, 1998. Longhurst,~A.: Ecological Geography of the Sea, 2nd edn., Academic Press, Amsterdam, 2007. Lozier,~M. and Gawarkiewicz,~G.: Cross-frontal exchange in the Middle Atlantic Bight as evidenced by surface drifters, J Phys. Oceanogr., 31, 2498–2510, 2001. Luettich,~R A., Westerink,~J J., and Scheffner,~N W.: ADCIRC: an advanced three-dimensional circulation model for shelves, coasts, and estuaries. Report 1. Theory and Methodology of ADCIRC-2DDI and ADCIRC-3DL, Tech. Rep. CERC-TR-DRP-92-6, Coastal Engineering Research Center Vicksburg, 1992. Mellor,~G L. and Yamada,~T.: Development of a~turbulence closure-model for geophysical fluid problems, Rev. Geophys., 20, 851–875, 1982. Mountain,~D.: Variability in the properties of shelf water in the Middle Atlantic Bight, 1977–1999, J Geophys. Res, 108, 1029–1044, 2003. O'Reilly,~J E. and Zetlin,~C.: Seasonal, horizontal, and vertical distribution of phytoplankton chlorophyll a~in the northeast US continental shelf ecosystem, Tech. Rep. 139, US Department of Commerce, 1998. O'Reilly, J. E. and 21 co-authors: Ocean color chlorophyll a algorithms for SeaWiFS, OC2, and OC4: Version 4. in: OÕReilly, J. E. and 24 co-authors: SeaWiFS postlaunch calibration and validation analyses, part 3, NASA Tech. Memo., 2000–206892, edited by: Hooker, S B and Firestone, E R., NASA Goddard Space Flight Center, Greenbelt, Maryland, 11, 9–23, 2000. Oschlies,~A.: Nutrient supply to the surface waters of the North Atlantic: a~model study, J Geophys. Res., 107(C5), 3046, doi:10.1029/2000JC000275, 2002. Pätsch,~J. and Kühn,~W.: Nitrogen and carbon cycling in the North Sea and exchange with the North Atlantic: a~model study. Part I. Nitrogen budget and fluxes, Cont. Shelf Res., 28, 767–787, 2008. Previdi,~M., Fennel,~K., Wilkin,~L., and Haidvogel,~D.: Interannual variability in Atmospheric \chemCO_2 uptake on the northeast US continental shelf, J Geophys. Res., doi:10.1029/2008JG000881, in press, 2009. Ramp,~S., Schlitz,~R., and Wright,~W.: The deep flow through the Northeast Channel, Gulf of Maine, J Phys. Oceanogr., 15, 1790–1808, 1985. Rossby,~T. and Benway,~R.: Slow variations in mean path of the Gulf Stream east of Cape Hatteras, Geophys. Res. Lett., 27, 117–120, 2000. Ryan,~J., Yoder,~J., and Townsend,~D.: Influence of a~Gulf Stream warm-core ring on water mass and chlorophyll distributions along the southern flank of Georges Bank, Deep-Sea Res. II, 48, 159–178, 2001. Schollaert,~S., Rossby,~T., and Yoder,~J.: Gulf Stream cross-frontal exchange: possible mechanisms to explain interannual variations in phytoplankton chlorophyll in the Slope Sea during the SeaWiFS years, Deep-Sea Res. Pt. II, 51, 173–188, 2004. Seitzinger,~S., Harrison,~J., Bohlke,~J., Bouwman,~A., Lowrance,~R., Peterson,~B., Tobias,~C., and Drecht,~G.: Denitrification across landscapes and waterscapes: a~synthesis, Ecol. Appl., 16, 2064–2090, 2006. Sieburth,~J M., Smetacek, V., and Lenz,~J.: Pelagic ecosystem structure: heterotrophic compartments of the plankton and their relationship to plankton size fractions, Limnol. Oceanogr., 23, 1256–1263, 1978. Smith,~P., Houghton,~R., Fairbanks,~R., and Mountain,~D.: Interannual variability of boundary fluxes and water mass properties in the Gulf of Maine and on Georges Bank: 1993–1997, Deep-Sea Res. II, 48, 37–70, 2001. Stow,~C A., Jolliff,~J.,, McGillicuddy~Jr.,~D J., Doney,~S C., Allen,~J I., Friedrichs,~M A., Rose,~K A., and Wallhead,~P.: Skill assessment for coupled biological/physical models of marine systems, J Marine Syst., 76, 4–15, 2009. Strom,~S L., Miller,~C B., and Frost,~B W.: What sets lower limits to phytoplankton stocks in high-nitrate, low-chlorophyll regions of the open ocean?, Mar. Ecol.-Prog. Ser., 193, 19–31, 2000. Taylor,~K E.: Summarizing multiple aspects of model performance in a~single diagram, J Geophys. Res.-Atmos., 106, 7183–7192, 2001. Thomas,~A., Townsend,~D., and Weatherbee,~R.: Satellite-measured phytoplankton variability in the Gulf of Maine, Cont. Shelf Res., 23, 971–989, 2003. Thomas,~H., Bozec,~Y., Elkalay,~K., and De~Baar,~H.: Enhanced open ocean storage of \chemCO_2 from shelf sea pumping, Science, 304, 1005–1008, 2004. Yoder,~J A., Schollaert,~S E., O'Reilly,~J E.: Climatological Phytoplankton Chlorophyll and Sea Surface Temperature Patterns in Continental Shelf and Slope Waters off the Northeast U.S. Coast, Limnol. Oceanogr., 47, 672–682, 2002.