An eddy‐permitting coupled physical‐biological model of the North Atlantic: 2. Ecosystem dynamics and comparison with satellite and JGOFS local studies data

Optimizing models of the North Atlantic spring bloom using physical, chemical and bio-optical observations from a Lagrangian float

“…Cysts are assumed to preserve the chlorophyll from diatoms, hence Chl 2 also sinks at that rate. This treatment of diatom sinking upon depletion of silicate is similar to that of Pondaven et al (2000). The Dirac delta function, δ, is used here to indicated the transfer of diatoms into cysts at time t Cys .…”

“…Biological model variables and parameters are listed in Table 2. The simplest model (1p1s) is similar in structure to the model of Oschlies and Garçon (1999), which has been used extensively for the North Atlantic in many follow-up studies (e.g., Oschlies et al, 2000;Oschlies, 2002), although here we included chlorophyll as a separate state variable to allow for photoacclimation and included the uptake of silicate by phytoplankton in addition to the uptake of nitrate. The other two model variants (2p1s and 2p2s) are similar in structure to the model of Lima and Doney (2004), which has also been applied to the North Atlantic, in that diatoms are represented as a separate phytoplankton group.…”

“…Data collected during extensive cruises and from moored sediment traps significantly improved our understanding of the vertical carbon and nitrogen fluxes (Buesseler et al, 1992;Martin et al, 1993) and the plankton community's response to nutrient depletion (Sieracki et al, 1993). Modelling studies (Oschlies et al, 2000;Waniek, 2003) showed the need for more extensive and detailed observations for validating the models. Previous work also emphasized the need for a more complete spatial and temporal coverage of the bloom to grasp the variability caused by the observed mesoscale eddy stirring (Washburn et al, 1998;Mémery et al, 2005).…”

“…Several marine ecosystem models have been developed in recent years for understanding, quantifying and predicting key biogeochemical processes in the oceans (e.g., Evans and Parslow, 1985;Fasham et al, 1990;Doney et al, 1996;Oschlies and Garçon, 1999;Pondaven et al, 2000;Fennel et al, 2003a,b;Lima and Doney, 2004). Before routine use of parameter optimization techniques, models were typically optimized by tuning parameters manually until the model output "fits" the observations (e.g., Fasham et al, 1990).…”

An operational biogeochemical model of the North-East Atlantic: Model description and skill assessment

“…The models vary in complexity from simple four-compartment Nitrate, Phytoplankton, Zooplankton, Detritus (NPZD) pelagic models (e.g. Oschlies et al, 2000) to more complex multi-nutrient and multi-functional group models (e.g. Lima and Doney, 2004;Vichi et al, 2007;Mateus, 2012) and benthic-pelagic models with over 40 state variables such as ERSEM, one of the most complex lower trophic-level marine ecosystem models in use (Baretta et al, 1995).…”