Maps of 3D LCSs for 4 Apr 1200Z to 8 Apr 1200Z 2019, Issued 4 Apr 2019

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 4 April 2019 to 8 April 2019.

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 (1/200 deg resolution)

96-hr Forecast 3D FTLE at 4 meters depth on April 8 1200Z

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Date 12:00Z
April 8
(Forward)
new_FTLE_forward_004m_96hr.png
April 8
(Backward)
new_FTLE_backward_004m_96hr.png

6-hr Forecast Forward 3D FTLE at 4 meters depth on four time instances for April 4 1200Z - April 6 0600Z

Start Date 12:00Z 18:00Z 00:00Z 06:00Z
April 4 new_FTLE_forward_004m_06hr_T0.png
new_FTLE_forward_004m_06hr_T1.png
new_FTLE_forward_004m_06hr_T2.png
new_FTLE_forward_004m_06hr_T3.png
April 5 new_FTLE_forward_004m_06hr_T4.png
new_FTLE_forward_004m_06hr_T5.png
new_FTLE_forward_004m_06hr_T6.png
new_FTLE_forward_004m_06hr_T7.png

6-hr Forecast Backward 3D FTLE at 4 meters depth on four time instances for April 4 1200Z - April 6 0600Z

Start Date 12:00Z 18:00Z 00:00Z 06:00Z
April 4 new_FTLE_backward_004m_06hr_T0.png
new_FTLE_backward_004m_06hr_T1.png
new_FTLE_backward_004m_06hr_T2.png
new_FTLE_backward_004m_06hr_T3.png
April 5 new_FTLE_backward_004m_06hr_T4.png
new_FTLE_backward_004m_06hr_T5.png
new_FTLE_backward_004m_06hr_T6.png
new_FTLE_backward_004m_06hr_T7.png
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