[ferret_users] interpolation

[David Wang <climater@xxxxxxxxx>]

Hey all,

Here I have a question that may not be very relevant, but...

I used Levitus climatology as the initial hydrographic fields for a 
z-coordinates model. My preprocessings include interpolating Levitus 
onto the model grid which generally is denser than Levitus' in the upper 
ocean and intact in depths. This was done in Ferret using simple 
implicit linear interpolation associated with regridding, something like

let tmp = theta[GX=newlon,GY=newlat];
let newtheta = tmp[GZ=newdepth];

I recently found that in Levitus dataset cell edges reside at the middle 
points between two adjacent grid points on z coordinates, not the 
opposite (i.e., grid points sit at the midpoints between two edges). I 
don't know if Ferret treats the two coordinate arrangements differently 
concerning regridding interpolation, or does it matter or not. 
Furthermore is there better (or more accurate) way to prepare these 
initial data?

Thanks, David