Re: How to compute the Potential vorticity (Rossby's form or Ertel' form) on isobaric surface?

小代 wrote:
> Dear guys,
> I want to compute the Potential vorticity (Rossby's form or Ertel'
> form) on isobaric surface
> , with the NCEP 1*1 global analysis data. How to do this in ncl.
> Thanks very much!
>
==========================
There is an *unsupported* NCL function that computes PV. It uses:

Bluestein: Synoptic-Dynamic Meteorology in Midlatitudes
pg 264 Eq 4.5.93

Note: the arrays must be ordered South-to-North in order to
evaluate the gradients via spherical harmonics. If the
NCEP data are (say) T(time,level,lat,lon) and are ordered
North-to-South, you will have to reorder all the arrays.
T = T(:,:,::-1,:) ; ::-1 will reorder the latitudes
U
V
It will be sent offline.
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Received on Wed Jan 02 2008 - 10:24:16 MST