On Tue, Feb 3, 2009 at 2:19 PM, Ousmane Ndiaye <span dir="ltr"><<a href="mailto:ousmane@iri.columbia.edu">ousmane@iri.columbia.edu</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi,<br>
I am using the function fish_chi to find the velocity potential from the horizontal wind components. The function works great but unfortunately the velocity potential that is defined is on the grid in longitude from 0 to 360 and is not periodic. This is an issue because I would like to display the data over the African continent only, i.e. from longitude 30W to 60E and latitude from 30S to 30N. I have tried to solve this problem by making the input data to the fish_chi function be periodic,<br>
i.e. longitude from 0 to 720. When I do this I get the error message:<br>
<br>
Error from fish: rc = 1000<br>
Operation Error: Error from fish function<br>
Operation Error: Error from fish_chi function<br>
Error ocurred at column 1<br>
DEFINE error: Invalid expression.<br>
<br>
Any suggestions on how I can overcome this issue would be greatly appreciated. Or anyone who has the Re-analysis daily velocity potential available that he want to share with.</blockquote><div><br>Try this:<br><br>open model<br>
set lon -180 180<br>set lev 200<br>chi = fish_chi(ua,va)<br>set lon -30 60<br>set lat -50 60<br>d chi<br><br>You should get the attached plot. The trick is to set the domain to [180W,180E] before calling the function.<br>
<br> Arlindo<br><br><br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>
<font color="#888888">Ousmane<br>
</font></blockquote></div><br><br clear="all"><br>-- <br>Arlindo da Silva<br><a href="mailto:dasilva@alum.mit.edu">dasilva@alum.mit.edu</a><br>