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|Authors: ||Vichi, M.*|
|Title: ||A generalized model of pelagic biogeochemistry for the global ocean ecosystem. Part II: numerical simulations|
|Title of journal: ||Journal of Marine Systems|
|Series/Report no.: ||1-4 / 64 (2007)|
|Issue Date: ||2006|
|Keywords: ||Global biogeochemical cycles|
Ocean general circulation model
|Abstract: ||This paper presents a global ocean implementation of a multi-component model of marine pelagic biogeochemistry coupled online
with an ocean general circulation model forced with climatological surface fields (PELAgic biogeochemistry for Global Ocean
Simulations, PELAGOS). The final objective is the inclusion of this model as a component in an Earth System model for climate
studies. The pelagic model is based on a functional stoichiometric representation of marine biogeochemical cycles and allows
simulating the dynamics of C, N, P, Si, O and Fe taking into account the variation of their elemental ratios in the functional groups.
The model also includes a parameterization of variable chlorophyll/carbon ratio in phytoplankton, carrying chl as a prognostic
variable. The first part of the paper analyzes the contribution of non-local advective–diffusive terms and local vertical processes to
the simulated chl distributions. The comparison of the three experiments shows that the mean chl distribution at higher latitudes is
largely determined by mixing processes, while vertical advection controls the distribution in the equatorial upwelling regions.
Horizontal advective and diffusive processes are necessary mechanisms for the shape of chl distribution in the sub-tropical Pacific.
In the second part, the results have been compared with existing datasets of satellite-derived chlorophyll, surface nutrients,
estimates of phytoplankton community composition and primary production data. The agreement is reasonable both in terms of the
spatial distribution of annual means and of the seasonal variability in different dynamical oceanographic regions. Results indicate
that some of the model biases in chl and surface nutrients distributions can be related to deficiencies in the simulation of physical
processes such as advection and mixing. Other discrepancies are attributed to inadequate parameterizations of phytoplankton
functional groups. The model has skill in reproducing the overall distribution of large and small phytoplankton but tends to
underestimate diatoms in the northern higher latitudes and overestimate nanophytoplankton with respect to picoautotrophs in
oligotrophic regions. The performance of the model is discussed in the context of its use in climate studies and an approach for
improving the parameterization of functional groups in deterministic models is outlined.
© 2006 Elsevier B.V. All rights reserved.|
|Appears in Collections:||03.04.01. Biogeochemical cycles|
03.01.07. Physical and biogeochemical interactions
Papers Published / Papers in press
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