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Next: 7.7.4 Technical details Up: 7.7 Potential vorticity Matlab Previous: 7.7.2 Equations   Contents

7.7.3 Key routines

  • A_compute_potential_density.m: Compute the potential density field. Requires the potential temperature and salinity (either total or anomalous) and produces one output file with the potential density field (file prefix is SIGMATHETA). The routine uses densjmd95.m a Matlab counterpart of the MITgcm built-in function to compute the density.
  • B_compute_relative_vorticity.m: Compute the three components of the relative vorticity defined in Eq. (7.1). Requires the two horizontal velocity components and produces three output files with the three components (files prefix are OMEGAX, OMEGAY and ZETA).
  • C_compute_potential_vorticity.m: Compute the potential vorticity without the negative ratio by the density. Two options are possible in order to compute either the full component (term into parenthesis in Eq. 7.3) or the planetary component ( $ f\partial_z\sigma_\theta$ in Eq. 7.4). Requires the relative vorticity components and the potential density, and produces one output file with the potential vorticity (file prefix is PV for the full term and splPV for the planetary component).
  • D_compute_potential_vorticity.m: Load the field computed with C_comp... and divide it by $ -\rho$ to obtain the correct potential vorticity. Require the density field and after loading, overwrite the file with prefix PV or splPV.
  • compute_density.m: Compute the density $ \rho $ from the potential temperature and the salinity fields.
  • compute_JFz.m: Compute the surface vertical PV flux due to frictional processes. Requires the wind stress components, density, potential density and Ekman layer depth (all of them, except the wind stress, may be computed with the package), and produces one output file with the PV flux $ J^F_z$ (see Eq. 7.6) and with JFz as a prefix.
  • compute_JBz.m: Compute the surface vertical PV flux due to diabatic processes as:
    $\displaystyle J^B_z$ $\displaystyle =$ $\displaystyle -\frac{f}{h}\frac{\alpha Q_{net}}{C_w}$  

    which is a simplified version of the full expression given in Eq. (7.5). Requires the net surface heat flux and the mixed layer depth (of which an estimation can be computed with the package), and produces one output file with the PV flux $ J^B_z$ and with JBz as a prefix.
  • compute_QEk.m: Compute the horizontal heat flux due to Ekman currents from the PV flux induced by frictional forces as:
    $\displaystyle Q_{Ek}$ $\displaystyle =$ $\displaystyle - \frac{C_w \delta_e}{\alpha f}J^F_z$  

    Requires the PV flux due to frictional forces and the Ekman layer depth, and produces one output with the heat flux and with QEk as a prefix.
  • eg_main_getPV: A complete example of how to set up a master routine able to compute everything from the package.


next up previous contents
Next: 7.7.4 Technical details Up: 7.7 Potential vorticity Matlab Previous: 7.7.2 Equations   Contents
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