hcurl

hcurl(uexpr,vexpr)

Calculates the vertical component of the curl (ie, vorticity) at each grid point using finite differencing on the grids provided. It is assumed that uexpr gives the U Wind component, and that vexpr provides the V Wind component.

Usage Notes

  1. The alghorithm used for the finite difference calculation is described as an Example for the cdiff function.

  2. The function assumes an X-Y varying dimension environment, and will not operate unless that is the case. The define command can be used in conjunction with the hcurl function to create 3 or 4 dimensional fields of vorticity, from which vertical cross-sections could be displayed.

  3. The boundaries of the grid are set to missing.

  4. The radius of the earth used in the calculation is in meters; thus the units of the wind expressions provided would normally be m/s.

Examples

  1. To display the vorticity:

    d hcurl(u,v)

  2. If you want to display a vertical cross section of vorticity, you first need to calculate it over a 3-Dimensional region:

    set lon 0 360
    set lat -90 90
    set lev 1000 100
    define vort = hcurl(u,v)
    set lon -90
    display vort