Publication Date:
2017-04-04
Description:
This paper presents a global ocean implementation of a multi-component model of marine pelagic biogeochemistry coupled on-line 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.
Description:
We thank the Goddard Space Flight Center DAAC for SeaWiFS and CZCS satellite data and Yves Dandonneau for the GeP&CO pigment data and methodological explanations. We also acknowledge the availability of data from the US and International JGOFS websites and from the World Ocean Database. We acknowledge the support by the EU projects ENSEMBLES [project no. GOCE-CT-2003-505539] and DYNAMITE [project no. 00393(GOCE)]. We thank Job Baretta and an anonymous reviewer for their critical comments, which helped us to improve the manuscript.
Description:
Published
Description:
110-134
Description:
3.7. Dinamica del clima e dell'oceano
Description:
JCR Journal
Description:
reserved
Keywords:
Global biogeochemical cycles
;
Ocean general circulation model
;
Ecosystem model
;
OPA
;
ERSEM
;
PELAGOS
;
03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling
;
03. Hydrosphere::03.01. General::03.01.07. Physical and biogeochemical interactions
;
03. Hydrosphere::03.04. Chemical and biological::03.04.01. Biogeochemical cycles
;
03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling
;
03. Hydrosphere::03.04. Chemical and biological::03.04.04. Ecosystems
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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