On the improvement of mapping oceanic surface fields from satellite observations

Abstract:

Recent studies highligth the significant role of submesoscale oceanic processes (O(10km)) and its impact on local and global ocean circulation and biology. While oceanic circulation models are crucial for predicting the evolution of the earth’s climate, model parameterizations for dynamics at submesoscales need to be further developed. A perequisite for such improvement is to further observe and understand the impacts of mesoscale and submesoscale dynamics at regional to larger scales. In this talk, two different techniques aiming to improve the resolution in oceanic observations surface fields maps are presented.

The first technique aims at improving the representation of small-scale ocean processes in sea level maps from altimetry. The current resolution of these maps constructed by a statistical optimal interpolation technique, is well adapted to the study of the mesoscale variability. However, mainly due to the spatio-temporal sampling of the data, it cannot capture structures smaller than 150-200km. A dynamic interpolation method is developped, based on a one-and-a-half layer quasi-geostrophic propagation model, toecreate part of the temporal evolution of small oceanic structures using the local dynamics.
The second technique aims at refining the resolution of tracer observations, such as temperature or salinity. Even though the mapped geostrophic currents estimated from altimetry only resolve the larger Eulerian mesoscale field, the temporal evolution of these 2D fields can be used used to stir surface tracers trough a Lagrangian lateral advection technique. This technique allows the reconstruction of fine-scale temperature and salinity structures associated with fronts and eddies.

Speaker Biography:
Marine Rogé recently obtained a Ph.D. in physical oceanography under the supervision of Rosemary Morrow and Clement Ubelmann in early 2018 from Universite Paul Sabatier, Toulouse, France. Her main area of investigation is physical oceanography with particular emphasis in surface fields and altimetry. She also worked three years as research engineer after having received both her M.E. degree in Hydrography and Oceanography and her M.Sc. in Ocean and Atmosphere Physics in 2010 in Brest (France).