Altimetry diagnostics

This section show comparisons on geostrophic velocities computed from Sea Level Anomaly (SLA)

  1. From Croco model, the SLA is computed from the difference between SSH and SSH integrated over the year.

    \[SLA(t)=zeta(t)-zeta_{mean}\]

    Then the EKE is computed from geostrophic velocities

    \[\begin{split}EKE=\frac{1}{2}*(u^{'2}+v^{'2}) \\ =\frac{g^2}{2f^2}*((\frac{-\partial{SLA}}{\partial{y}})^2+(\frac{\partial{SLA}}{\partial{x}})^2)\end{split}\]

  2. The Altimetry products used here are AVISO products which provide directly the components of geostrophic velocities ugosa and vgosa

    https://www.aviso.altimetry.fr/en/data/product-information/aviso-user-handbooks.html

  3. Filtering of Data

    Once the EKE is computed for both Data and model, a temporal filter is applied to separate the low and high components. The filter used is the butterworth filter with a cut-off frequency of 100 days.

  4. What plots ?

    • Maps of low and high passed EKE comparisons

    • Spatial mean over the differents basins in mediterranea and plot of the time series

    _images/eke_low_pass.png _images/eke_time_serie_low_pass.png _images/eke_high_pass.png _images/eke_time_serie_high_pass.png _images/eke_all_pass.png _images/eke_time_serie_all_pass.png

  5. What scripts ?

    diags_alti.ipynb is the notebook to use to compute and do the plots