Tidal harmonics and ellipses

Complex Field

Most tidal harmonics are stored in amplitude and phase lag (FES, SYMPHONIE, MIOST-IT, etc.) but some of them are also stored in real and imaginary part (HRET).

Setup for amplitude/phase complex variables:

  1. Primary menu → [file name] → [amplitude variable], then Secondary menu → p → interp

  2. Primary menu → [file name] → [phase variable], then Secondary menu → p → phase

Tidal Harmonics

Setup for real/imaginary complex variables:

  1. Primary menu → formulaAndIso → p = re + 1j*im, j refers to the imaginary unit ( j² = -1 ).

  2. Primary menu → [file name] → [real variable], then Secondary menu → re → interp

  3. Primary menu → [file name] → [imaginary variable], then Secondary menu → im → interp

Isophases:

  1. Primary menu → formulaAndIso → pG = -arg(p)*r2d

  2. Select pG

  3. View window → display → Select formula variable settings… [F12]

  4. isovalues → -180 *30 180 → Apply

Tidal ellipses:

By setting complex velocities on u and v the arrows will become ellipses and the colored field will refers to the amplitude of the velocity field.

Primary menu → [file name] :

  1. [U amplitude variable], then Secondary menu → u → interp

  2. [U phase variable], then Secondary menu → u → phase

  3. [V amplitude variable], then Secondary menu → v → interp

  4. [V phase variable], then Secondary menu → v → phase

TIPS: When manipulated heavy files, check the “freeze” box in the View window before setting all the variable, then uncheck it to apply all the changes at once

Tidal Ellipses