Maps of the MSEAS forecast 3D LCSs for 11 Mar 1200Z to 15 Mar 1200Z 2022, Issued 12 Mar 2022

The following figures show the 3D Finite-Time Lyapunov Exponents (FTLEs) on the surface in the domain, at different times. These FTLEs are for a time window of 6 or 96 hours for the forecast of 11 March 2022 1200Z to 15 March 2022 1200Z.

The figures below show the 3D FTLEs in the domain, at different times. These FTLE computations are for a time window of 6 or 96 hours for the forecasts on the dates as specified. 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 3D FTLE field specifies the amount of stretching of the flowmap in the considered time interval. Specifically, the forward / backward 3D 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.

As a reminder, 12:00Z = 13:00 CET, i.e., CET is 1 hour ahead of Zulu time.

Calypso Domain (900m resolution)

96-hr Forecast 3D FTLE at 0 meters depth on March 15 1200Z

Date	12:00Z
March 15 (Forward)
March 15 (Backward)

6-hr Forecast Forward 3D FTLE at 0 meters depth on four time instances for March 11 1200Z - March 15 1200Z

Start Date	12:00Z	18:00Z	00:00Z	06:00Z
March 11 (12Z,18Z); March 12 (00Z,06Z)
March 12 (12Z,18Z); March 13 (00Z,06Z)