CALYPSO Real-Time Balearic Sea Experiment 2022

Balearic Sea – February-March 2022

Nowcast and Forecast Products Descriptions

Ocean Physics
These are central forecasts of the ocean fields. Horizontal maps, at several depths both above and below the mixed-layer depth are provided in two formats: a static, snapshot time-series of the estimated ocean state every 6 hours, and an interactive format. Vertical section maps, which transect the operational area and contain the density fronts, are also provided as a snapshot time-series. For columns with two Xs, the left "X" links to the ocean physics forecast from the standalone MSEAS-PE run (900m res); the right "X" links to the forecast from the high-resolution implicit 2-way nested MSEAS-PE run (900m resolution Balearic Sea domain and 300m resolution process domain).
Interactive Flow Maps
Forward flowmaps display at the initial location of a water parcel the final position of that water parcel as it is advected over a specified time window. For instance, if the value of the 96 hour forward z-flowmap at a given (x, y, z) location is 50m, the final depth of that point will be 50m after 96 hours of being advected in the flow. Hence, the z-flowmap for example does not indicate where the water parcel goes down nor where it ends up.
Backward flowmaps display at the final location of a water parcel the initial position of that water parcel as it is advected over a specified time window.
Lagrangian Coherent Structures
The figures in this row show the finite-time Lyapunov exponents (FTLEs) in the domain, at different times. These FTLE computations are for a time window of 6 or 96 hours for the forecasts on various dates as specified in the figures captions. The flowmaps were calculated using a PDE-based approach with 5th order spatial and 3rd order temporal schemes, and a novel composition based approach.

The FTLE field specifies the amount of stretching of the flowmap in the considered time interval. Specifically, the forward / backward FTLE is a logarithmic scaling of the dominant singular values of the forward / backward flowmap with the time duration of interest. The forward FTLE ridges thus highlight codimension-one manifolds (curves in 2D, surfaces in 3D) that repel particles starting on either side, whereas the backward FTLE ridges highlight codimension-one manifolds that attract particles towards the ridge that originally start far apart.
Drifters
The figures in this row of the table show the trajectories in the domain for a given time interval. For this project, the drifters are released at every 10 grid points, and the grid has a model resolution of 900m. These trajectory computations correspond to time windows of 48 and 72 hours, for the forecasts specified in the headers of the respective columns.
Special Lagrangian Products
Special products, commonly still images, of our MSEAS forecasts of the ocean physics and Lagrangian 3D transport of waters (e.g. waters starting at various depths).

What is plotted is the depth reached by the water parcel by the end of the forecast, starting on a specific date and time at that (x, y, z) location (i.e., it does not show the horizontal displacement of the parcel, only the depth reach by a parcel released at x, y, z).

For the 3D+time Lagrangian subduction of waters, what is shown are the motions in 3D of water volumes that subduct the most from the surface layers to deeper layers (computed based on our forward flowmap forecast).

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