GODAE is sponsored by
5.7 Integrating Biogeochemistry and Ecology into Ocean Data Assimilation Systems
Lead authors: Pierre Brasseur (CNRS/LEGI) and Nicolas Gruber (ETHZ)
Author/co-authors: P. Brasseur1, N. Gruber2, R. Barciela3, K. Brander4, A. Hobday5, M. Huret6 , P.Lehodey7, C. Moulin8, R. Murtugudde9, I. Senina7 , E. Svendsen10, R. Matear5
1CNRS/LEGI, Grenoble, France
2ETH, Zürich, Switzerland
3Met Office, Exeter, United Kingdom
4ICES ,Copenhagen,Denmark
5CSIRO,Hobart,Australia
6Ifremer,Brest,France
7CLS ,Ramonville-St-Agne,France
8CNRS/LSCE ,Gif-sur-Yvette, France
9ESSIC, Washington,USA
10IMR, Bergen, Norway
Abstract
Although the first generation of operational oceanography systems has been designed to routinely estimate the state of the oceans' physical environment, there is considerable opportunity to expand the GODAE systems in order to include new models and assimilation components relevant to marine biogeochemistry and higher trophic levels. This expansion is a key challenge in an era of climate change requiring well-planned strategies supported by appropriate data to safeguard marine ecosystems. In this presentation, we will discuss some of the applications and limitations of operational oceanography systems to deliver ecological and biogeochemical products, as examined by the joint IMBER-GODAE working group.
A number of GODAE systems have already demonstrated potential to deliver products for (i) representing primary production using more realistic ocean dynamics at eddy scales to constrain the biological activity in the open ocean and upwelling systems; (ii) monitoring the oceanic component of the carbon cycle; (iii) modelling the mid-trophic component of the pelagic system using horizontal transport and primary production; (iv) physical and biogeochemical fields and/or time series needed for functional groups and higher trophic level species habitat prediction models; (v) studies of longer term variability and shifts in ecosystems based on decadal reanalyses of the ocean circulation and primary production, and (vi) regional modelling of ecosystems and water quality management in coastal areas by providing boundary conditions to estimate fluxes and cross-slope exchanges.
A number of applications, however, indicate that the GODAE systems need to improve the representation of physical state variables that currently are not yet considered as essential, such as vertical velocity, mixed layer depth, stratification and vertical mixing. These variables are important as they have direct impacts on biology. Additional issues to be addressed relate to the representation of physical processes in the GODAE products, on-line vs. off-line strategies and requirements for long-term re-analyses of coupled models. With regard to living resources, coupling between open ocean and shelf seas also raises issues concerning the modelling of critical physical processes at their interface, particularly as exchanges are in both directions. In the future, an extension of the "integrated" approach developed during GODAE for the physics to coupled physical-ecological-biogeochemical models will require further developments of the observing systems, both in terms of in situ platforms (with intensified deployments of sensors for O2 and chlorophyll, and inclusion of new sensors for nutrients, zooplankton and micronekton biomass etc.), ocean colour satellite missions (possibly on geostationary orbits), and improved methods to assimilate these new measurements. The extension of the GODAE metrics concept to biogeochemical variables will also be needed to measure progress and coordinate efforts of the international community in the longer term.
Keywords: Ecosystems, biogeochemistry, fisheries, modelling, data assimilation, prediction
(Last Updated: 13-10-2008)