December 29, 2004: We have implemented an ocean biogeochemistry model in POP version 2.0. The model is based on the ecosystem model of Doney, Moore and Lindsay (Moore et al. 2002, Deep-Sea Res., 49B, 403-462) with a trace gas module as described in a paper by Chu et al (Earth Interactions,Volume 8 (2004), Paper No. 11, available here) . The ecosystem model provides the carbon species while the trace gas module provides a variety of other important species including dimethyl sulfide (DMS), the most important ocean contribution to the sulfur cycle. Many integrations of the above model in ocean only simulations have been completed for model validation and for the improvement and calibration of biogeochemical model processes and parameters.
The version of POP 2.0 with the embedded biogeochemical model as described above has been successfully coupled within CCSM3. A five year simulation has been completed with the fully-coupled system at coarse resolution (T42 atmosphere, x3 ocean). All components, including the ocean biogeochemistry, were fully interacting with and responding to the physical fields from all other components. In addition, the ocean biogeochemistry model in this simulation provided both carbon dioxide and DMS to the coupler and we have verified that the coupler has correctly processed this data through interpolation, time averaging and merging for use in the atmosphere model. However, the carbon and sulfur coupling was only one-way (ocean to atmosphere) with no interaction with any atmospheric chemistry. No formal validation of this five-year simulation has yet occurred, but the model ran stably and the results were qualitatively reasonable when compared to existing control simulations.
The CCSM3 simulation described above and the Earth Interactions publication are evidence that we have successfully implemented an ocean biogeochemistry model that includes the effects of carbon and sulfur species in the current version of POP and that we have successfully implemented such a model within the CCSM3.