Hi Muse,

The trick is simple. Just overlay a line where the zonal wind, u=0 on your vectors.

Cheers.

In addition, you can try using vector operations:

http://cola.gmu.edu/grads/gadoc/functionsatt.html

hcurl() : Calculates the vertical component of the curl hdivg() : Calculates the horizontal divergence using finite differencing mag() : Calculates the wind speed given u,v components skip() : Sets alternating data values to missing