Vertical motion associated with mesoscale oceanic features is of fundamental importance for the exchanges of heat, fresh water and biogeochemical tracers between the surface and the ocean interior. Unfortunately, direct measurements of the vertical velocity are difficult to obtain for typical values (order 10’s m/day). Various indirect methodologies have thus been proposed to estimate vertical velocity from observed density and geostrophic velocity fields. The most used technique is based on the solution of the quasi-geostrophic Omega equation that has traditionally been applied to individual field campaigns without any temporal repetitivity.
In this context, the main objective of this proposal is to improve our quantification and understanding of vertical exchanges associated with oceanic mesoscale features through the combined use of satellite altimetry, in-situ data and numerical models. Several areas of the World Oceans will be selected and the influence of vertical motion on surface oceanic chlorophyll will be also explored. The hypothesis behind these relationships relies on the fact that significant variations in the vertical exchange associated with mesoscale dynamics could affect ocean ecosystems, an issue that is not well understood and remains hotly debated.
The approach chosen to achieve the MARINA objective presents several original and innovative elements, related to the methodologies proposed to analyze the physical and biological data, applying quasi-geostrophic diagnostic numerical models to different model and observational products. This project will benefit from existing 3D data sets and reanalysis generated in the frame of several EU funded projects. The MARINA aims are closely related to the purpose of the Joint Research Announcement and, in particular, they are in line with the program objectives for the Ocean Surface Topography Science Team (‘To support studies in physical oceanography utilizing Jason-series mission data, as well as the combined TP/Jason/Jason-2 data, preferably jointly wit other satellites and in situ data and/or models, in support of basic research applications’).
The members of this proposal have experience in the above-described activities as they have published several relevant papers in the last 20 years. More specifically, in the last years their contributions provide the basis and approach for the present project. More in detail, the research group has experience in (1) studying mesoscale dynamics with satellite altimetry (e.g. Rio et al. 2004; Pascual et al., 2006; Pascual et al., 2009; Rio et al. 2010); (2) developing and testing methods for reconstructing 3D fields from a combination of satellite and in situ data (Pascual et al. 2003; Guinehut et al. 2004; Guinehut et al. 2006; Guinehut et al. 2012) (3) estimating and analyzing vertical motion using Quasi-Geostrophic dynamics applied to in situ data (Pascual et al., 2004, Flexas et al., 2006) and to a combination of satellite altimetry and new autonomous underwater vehicles (Ruiz et al., 2009); and (4) exploring alternative mechanisms that can affect ocean ecosystems (González-Quirós et al., 2004; Pascual et al. 2004). In the last 10 years, the coordinator of the group has participated in and/or lead several national and European funded projects (CAÑONES, BIOMEGA, SINOCOP, MESCLA) as well as international initiatives (Saral/Altika announcement of opportunity, Ocean Surface Topography Science Team) where the problems proposed in this research have been identified as key elements to be solved in the coming years.