Hi Jaison (and all), Thanks for your excellent summary of the solutions.However, I did split the calculation along time axis for each time step (one month apart).
4. Remember that Ferret is not an "immediate evaluator" by default, and
it does so only when you force with grave accents (``). Hence you
can write all the calculation steps before the writing out part.
I always thought this was true, so that calculation on each time step would only require the memory for xyz grid points. But in practice at least in my case, I notice that the memory used by ferret, shown by "top" command, actually accumulates with the number of time steps, until it reaches the maximum memory of my linux workstation and leads ferret to crash. This was the reason that I can only do the calculation for a limited number of time steps. I tried "cancel memory", "cancel variable", and even "cancel data" and reread in data: Nothing works. In the end I had to quit ferret after certain time steps, and restart and continue on. Has anybody noticed this?
BTW, I read in data through DODs server. Best, Dongxiao