Total annual precipitation

[Ben Burford]

Hello Grads Masters,

I have a netcdf global 1 degree by 1 degree gridded file with 8 years of
daily precipitation data (mm/day).  For each grid cell I want to:
1. add up the total daily amounts of precipitation (for the entire time
series), and divide by 8 (to get the average annual total precipitation).
2. display this (global 2D plot). and
3. save this into a file for later use by another function.

I imagine this will be fairly simple, but I'm a beginner and I don't know
what functions are needed or how to set up the syntax.

Thanks in advance for any help.

Ben