Positive Vorticity Advection

[Wolfgang Linder]

Hello,

this works for me:

'define vort = hcurl(u,v)*100000'
'define dvortx = cdiff(vort,x)'
'define dvorty = cdiff(vort,y)'
'define dx = cdiff(lon,x)*3.1416/180'
'define dy = cdiff(lat,y)*3.1416/180'
'set gxout contour'
'define vortadv = (-1*( (u*dvortx)/(cos(lat*3.1416/180)*dx) +
v*dvorty/dy )/6.37e6)*3600*3'
'set clevs 10 20 40 60 80'
'd vortadv'
'set clevs -80 -60 -40 -20 -10'
'd vortadv'

Best regards

Wolfgang



Gianni Messeri wrote:

>    Hi all,
>    I want to calculate PVA and I use the following script:
>
>                define vort = hcurl(u,v)
>
>   2.
>          |define dtx = cdiff(vort,x) |
>          define dty = cdiff(vort,y)
>          define dx = cdiff(lon,x)*3.1416/180
>          define dy = cdiff(lat,y)*3.1416/180
>          display -1*( (u*dtx)/(cos(lat*3.1416/180)*dx) + v*dty/dy
> )/6.37e6
>
> I expected maximum values of PVA of 40-50 10e-9/Se2, but my values are
> greater (up to 350).
>
> Can anyone help me?
>
> Thanks in advance
>
> Gianni
>
>
> --
> Gianni Messeri
> La.M.M.A (Laboratorio Meteorologia e Modellistica Ambientale)
> CNR-IBIMET (National Research Council - Institute of BioMeteorology)
> Edificio D - via Madonna del Piano - 50019 Sesto Fiorentino (FI) - Italia
> Tel. +39 0554483033; Fax +39055444083
> Web: www.lamma.rete.toscana.it
> Web: www.ibimet.cnr.it
> --------------------------------
>


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Dr.Wolfgang Linder                  Tel:(+41)(0)31 307 26 26
METEOTEST                           Fax:(+41)(0)31 307 26 10
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