Capturing eddy shedding in the Gulf of Mexico from Lagrangian observations

The nonlinear process of eddy shedding is studied in the context of the Gulf of Mexico. We show that model runs which do not include eddy detachment can reproduce such an event with the assimilation of suitable data obtained from a control run with eddy detachment. This works surprisingly well and with small amounts of data provided the data originates from instruments that are carried by the flow, i.e. Lagrangian. This is compared with analogous assimilation of data from fixed stations which capture the eddy poorly. The remarkable efficacy of Lagrangian data assimilation in this context is explained by considering the structure of the correlation functions and their associated regions of influence.