how to calculate the difference between the two latitudes

[Davide Sacchetti]

the best solution would be to create a function (in a different
language) doing this, anyway:

suppose your variable is named "stream" and suppose you are interested
to a latitude interval of 40N - 60N
if you want to see latitude where stream is positive:
  d maskout(lat,stream)
if you want to see at which inferior latitude stream becomes positive:
  d min(maskout(lat,stream),lat=40,lat=60))
if you want to have the la difference (sup-inf) where stream = 0:
  display
max(maskout(lat,stream),lat=40,lat=60))-min(maskout(lat,stream),lat=40,lat=60))

Hoping it could help ...
bye bye
Davide



On Mon, 2009-11-02 at 21:50 -0500, Phillip Lin wrote:
> Hi everyone,
>
> I need to solve a problem: namely get the difference between the two
> latitudes at which the mass stream function equals zero, between these two
> zero values there is a maximum value usually. And the grid values about
> the mass stream function phim (lat,pressure) are from a netCDF data file.
> So how can I get the difference between these two latitudes with zero
> stream function? Do I need to convert netCDF to the other .dat file by
> using ncdump tool , and then use F90 to do the simple calculation to solve
> my problem, or am I able to only use GrADS scripting language to do the
> simple calculation? Or any other way to solve this?
>
> I will appreciate any help !
>
> Phillip
>
--
Sacchetti Davide
Centro Funzionale Meteo Idrologico di Protezione Civile della Regione Liguria
ARPAL Unità Tecnica Complessa di livello Regionale
V.le Brigare Partigiane 2 16121 Genova (I)
tel: +39 010 6437535                    fax: +39 010 6437520
mail: davide.sacchetti at arpal.org     web: www.meteoliguria.it