[gradsusr] How to get the latitude values in a Hovmoller Diagram?

[Joseph Basconcillo]

Hi, all:

I have time-latitude hovmoller diagram of annual OLR that is equal to 250wm-2. Time is the y-axis and latitude is the x-axis. I want to to obtain the latitude of OLR (=250wm-2) per year that is bounded by 30-50N. Can you help me in getting the latitude values per year? Thank you.

Yours,

JOSEPH Q. BASCONCILLO 
Weather Specialist 
Philippine Atmospheric, Geophysical and Astronomical Services Administration 
Diliman, Quezon City, Philippines