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20010319: gempak units/contours



James,
I was not able to view your attatched gif.

Some reasons why a contour plot would have regions uncontoured:
1) you have requested more than the maximum number of contour levels
2) There is missing data values (-9999.) for at least one of the
   parameters used in the computation at those grid points (or
   check for "negative" mixing ratio or relh values at those points).

When dealing with computations, the most significatnt is mixing ratio
is used in non-dimaensional units (eg g/g rather than g/kg as you normally
use in output- eg there is a 10^3 term here). Omega computations are generally
carried out in SI units of Pa S-1 (10^2 magnitude here).I'd have to see what
your omega calculation is involving, but you will want to make sure that
terms of equations are properly handled in units. If you can let me know 
what the calculation is that you are seeing scaled 10^1 too high, I can
take a look.

Steve Chiswell
Unidata User Support

On Mon, 19 Mar 2001, J. Correia wrote:

> hello-
> have you ever seen a problem whereby gempak, say in a calculation of
> advection of mixing ratio at a level, has contours, but certain areas
> remain uncontoured? i will enclose the plot to show you what i mean...
> i dont have the code that calculated it, yet, but i can send that if need
> be. we are using eta model grids.
> 
> also, the units for omeg are mb/s. however when using omeg to calculate
> other fields, we are getting the term to be an order of magnitude larger
> than scaling suggests...is there any trick to use omeg in calculations.
> oh yeah, we are still using gempak 5.4, i believe.
> thanks for any assistance.
> james correia jr
> will hession
> 
>