CDO

All,

This is probably a FAQ, but I want to make sure I just don't do dumb things. I'm mainly a programmer, not a climate scientist.

Namely, I have some pictures I'm making of total precipitation (mm/day) at various resolutions, showing why finer and finer resolution is a Good Thing(TM). Each picture is over the same lat-lon box. So, what I was thinking was "I wonder if the total mass of water in each picture is the same", i.e., my 2-degree plot is all blocky, but the cells are big and all colored, while at 1/4-degree, much is now zero, but some gridcells are very high value. Now, I'm thinking to get the mass of water, I essentially need the volume. I have mm/day and I essentially would need to get the area of each cell and use that (and then get time step, etc.).

I guess my main question is: is fldsum() the operator I'd want? I'd think so, except it doesn't seem to have the area weights as part of its description in the doc. So, would I need to provide that separately? All my data are on lat-lon grids (nothing fancy) so it wouldn't be hard to calculate the grid area, I just didn't output it the first go around! (Running the globe at 6 km is...taxing.)

Am I on the right track?

Thanks,
Matt