Planetary waves play an important role in the dynamics of the oceans. With the development of satellite measurements, it finally became possible to observe planetary waves in Sea Level Anomalies from radar altimeters (e.g. Chelton and Schlax, 1996; Cipolli ni et al., 1997) as well as in Sea Surface Temperature from infrared sensors (e.g. Hill et al., 2000). Recently, several authors have studied westward propagating features associated with planetary waves in ocean colour data (chlorophyll-a concentration) (e.g. Machu et al., 1999; Cipollini et al., 2001; Uz et al., 2001; Charria et al., 2006). The observations of such signals prompt the question of how planetary waves influence primary, new and exported productions. Several physical/biological processes, which might be involved, have been suggested.
They are investigated using theoretical models and compared to the remotely sensed observations in a recent paper by Killworth et al. (2004). In this paper, it is pointed out the importance of the meridional advection of chlorophyll by geostrophic currents associated with planetary waves at global scale with a strong local contribution of vertical processes as shown in a following paper by Charria et al. (2006) in the North Atlantic. The aim of the present project is precisely to assess quantitatively the role of planetary waves on the biogeochemical system in different regions of the global ocean, by using remotely sensed data and realistic coupled physical/biogeochemical models.
The strategy of the project is to look at the differences in wave characteristics amongst different long datasets (from 1992 onwards), which will allow investigating on the underlying processes. It will then be tested and quantified with physical-biogeochemical modelling. At the time of writing, a quantitative measurement of the influence of planetary waves on the biogeochemical system in many oceanic regions is badly missing in order to better quantify and understand the global carbon cycle.
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