US Joint Global Ocean Flux Study

The first Regional Ecosystem Modeling Testbed Project Workshop was held 31 March – 02 April 2003 at the Center for Coastal Physical Oceanography, Old Dominion University. Fourteen scientists from eleven different institutions attended this highly successful meeting, including:

The goals of the workshop, as outlined at the JGOFS SMP Summer 2002 Meeting in Woods Hole, were (1) to increase awareness of the similarities and differences between the various ecosystem models currently in use by the attending JGOFS investigators, (2) to compare simulations from multiple ecosystem models using a standard physical framework and identical validation data, (3) to develop methodologies for characterizing the strengths/weaknesses of the different models, and (4) to provide instruction on the use of the adjoint method as applied to one-dimensional ecosystem models. 

Results stemming from this workshop were presented in a collaborative poster at the JGOFS Open Science Meeting in May 2003. The possibility of extending this analysis into a submission to the final JGOFS SMP DSRII volume was also discussed. 

Prior to the workshop, participants were provided with the testbed framework, which included Fortran routines for processes including advection, diffusion, mixing, sinking, and attenuation. In addition, standard forcing time series (mixed layer depth, vertical and horizontal advection, solar radiation), initial conditions, and biogeochemical validation data (chlorophyll-a, zooplankton biomass, nitrate, sediment trap, primary production) were provided. Each participant was responsible for plugging his/her ecosystem model subroutine into the testbed framework, and providing time series of ecosystem model output (plankton, nutrients, etc...) Friedrichs synthesized these results and presented the model comparisons for discussion at the workshop. 

A second component of the workshop entailed a tutorial on the adjoint method, as applied to one-dimensional ecosystem models. On the third day participants had the opportunity to use on-site computational facilities to develop the adjoint code for their specific ecosystem model, or revise their ecosystem model to enhance performance in relation to the other models presented. The workshop was marked by many lively discussions addressing topics such as the formulation of the cost function and the utility of the automatic adjoint compiler. Excellent presentations on the variational adjoint method, the utility of the automatic adjoint compiler and a posteriori error analyses were made by workshop participants. In addition, the collaborative synthesis poster for the JGOFS Open Science Meeting was outlined, the feasibility of submitting a paper for the final DSRII SMP volume was discussed, and plans for the second Regional Ecosystem Modeling Testbed Project Workshop were made. One of the highlights of the meeting was also the fact that by the conclusion of the workshop, the adjoint for most of the eleven participating models had been written.

• Workshop1_agenda

• Testbed Software and forcing used at this workshop

• Documentation describing use of testbed software

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Written by J. Klinck, April, 2003. Last updated by M. Friedrichs, September, 2004.

Send questions or comments by e-mail to marjy@ccpo.odu.edu