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Split-domain calibration of an ecosystem model using satellite ocean colour data

By J.C.P. Hemmings, M.A. Srokosz, P. Challenor and M.J.R. Fasham

Abstract

The application of satellite ocean colour data to the calibration of plankton ecosystem models for large geographic domains, over which their ideal parameters cannot be assumed to be invariant, is investigated. A method is presented for seeking the number and geographic scope of parameter sets which allows the best fit to validation data to be achieved. These are independent data not used in the parameter estimation process. The goodness-of-fit of the optimally calibrated model to the validation data is an objective measure of merit for the model, together with its external forcing data. Importantly, this is a statistic which can be used for comparative evaluation of different models. The method makes use of observations from multiple locations, referred to as stations, distributed across the geographic domain. It relies on a technique for finding groups of stations which can be aggregated for parameter estimation purposes with minimal increase in the resulting misfit between model and observations.<br/>The results of testing this split-domain calibration method for a simple zero dimensional model, using observations from 30 stations in the North Atlantic, are presented. The stations are divided into separate calibration and validation sets. One year of ocean colour data from each station were used in conjunction with a climatological estimate of the station’s annual nitrate maximum. The results demonstrate the practical utility of the method and imply that an optimal fit of the model to the validation data would be given by two parameter sets. The corresponding division of the North Atlantic domain into two provinces allows a misfit-based cost to be achieved which is 25% lower than that for the single parameter set obtained using all of the calibration stations. In general, parameters are poorly constrained, contributing to a high degree of uncertainty in model output for unobserved variables. This suggests that limited progress towards a definitive model calibration can be made without including other types of observations

Topics: GC
Year: 2004
OAI identifier: oai:eprints.soton.ac.uk:217
Provided by: e-Prints Soton

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  1. (1979). A comparison of three methods for selecting values of input variables in the analysis of output from a computer code. doi
  2. (2001). A data assimilative marine ecosystem model of the central equatorial Pacific: Numerical twin experiments. doi
  3. (1985). A model of annual plankton cycles.
  4. (1990). A nitrogen-based model of plankton dynamics in the oceanic mixed layer. doi
  5. (1967). A one-dimensional model of the seasonal thermocline. II: the general theory and its consequences. doi
  6. (1999). A pelagic ecosystem model calibrated with BATS and OWSI data. doi
  7. (1996). A pelagic ecosystem model calibrated with BATS data. doi
  8. (1993). A seasonal three-dimensional ecosystem model of nitrogen cycling in the North Atlantic euphotic zone. doi
  9. (2000). An eddy-permitting coupled physical-biological model of the North Atlantic 2. Ecosystem dynamics and comparison with satellite and JGOFS local studies data. doi
  10. (2003). Assimilating satellite ocean colour observations into oceanic ecosystem models. doi
  11. (2002). Assimilation of JGOFS EqPac and SeaWiFS data into a marine ecosystem model of the central equatorial Pacific Ocean. doi
  12. (1996). Assimilation of surface data in a one-dimensional physical-biogeochemical model of the surface ocean. 1. Method and preliminary results. doi
  13. (1996). Assimilation of surface data in a one-dimensional physical-biogeochemical model of the surface ocean. 2. Adjusting a simple trophic model to chlorophyll, temperature, nitrate and pCO2 data. doi
  14. (2002). Biogeochemical modelling of the tropical Pacific Ocean. I: seasonality and interannual variability. doi
  15. (1981). Calculating solar radiation for ecological studies. doi
  16. (1982). Climatological Atlas of the World Ocean. doi
  17. (2001). Configuring an ecosystem model using data from the Bermuda Atlantic Time Series (BATS). doi
  18. (1998). Data assimilation and a pelagic ecosystem model: parameterization using time series observations. doi
  19. (1994). Documentation and description of surface solar irradiance data sets produced for SeaWiFS. A draft document dated 10/30/94. Lamont Doherty Earth Observatory,
  20. (1998). Ecological Geography of the Sea. doi
  21. (1998). Eddy-enduced enhancement of primary production in a model of the north Atlantic Ocean.
  22. (1988). Estimates of winter-time mixed layer nutrient concentrations in the North Atlantic. doi
  23. (2000). Formation of an Azores Current due to Mediterranean overflow 58in a modeling study of the North Atlantic. doi
  24. (1991). ISCCP cloud data products. doi
  25. (2001). Model-derived estimates of new production: new results point towards lower values. doi
  26. (1988). Nonparametric Statistics for the Behavioural Sciences. doi
  27. (1992). Numerical Recipes in C: the Art of Scientific Computing. doi
  28. (1997). Observations of surface forcing from the subduction experiment: A comparison with global model products and climatological datasets. doi
  29. (2001). Parameter estimates of a zero-dimensional ecosystem model applying the adjoint method. doi
  30. (1995). Parameter optimization and analysis of ecosystem models using simulated annealing: A case study at Station P. doi
  31. (2001). Production and export in a global ocean ecosystem model. doi
  32. (1995). Regionally and seasonally differentiated primary production in the North Atlantic. doi
  33. (1992). Salinity-driven thermocline transients in a wind-forced and thermohaline-forced isopycnic coordinate model of the North Atlantic. doi
  34. (1998). Science quality SeaWiFS data for global biogeochemical research.
  35. (2000). Sea-air CO2 fluxes and carbon transport: a comparison of three ocean general circulation models. doi
  36. (1999). Sensitivity of ecosystem parameters to simulated satellite ocean color data using a coupled physical-biological model of the North Atlantic. doi
  37. (1972). Temperature and phytoplankton growth in the sea. doi
  38. (2000). Testing a marine ecosystem model: sensitivity analysis and parameter optimization. doi
  39. (1995). The lognormal distribution as a model for bio-optical variability in the sea. doi
  40. (1999). The role of local models and data sets in the Joint Global Ocean Flux Study. doi
  41. (1995). The use of optimization techniques to model marine ecosystem dynamics at the JGOFS station at 47◦N 20◦W. doi
  42. (2001). Tracking the SeaWiFS record with a coupled physical/biogeochemical/radiative model of the global oceans. doi
  43. (1998). World Ocean Atlas

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