[CF-metadata] Using cell methods for statistics associated with gridded observation data

From: Jonathan Gregory <j.m.gregory>
Date: Wed, 3 Jul 2013 15:51:45 +0100

Dear Randy

> The cell method "sum" is applied to the "time" and "y" and "x" coordinate
> variables The reason "sum" is used for the "time" coordinate variable is
> that the sensing of a region (i.e.cell) occurs over a several minute
> period. The sensing associated with a particular observation/pixel in the
> region (i.e. cell) happens in less than a second. Statistics associated
> this cell in time are really an accumulation over the several minute
> sensing period.

OK, I see. The observation is a formed from a sum. Nonetheless, is the
geophysical quantity really a sum? Is it extensive in time? For instance, if
conditions stayed exactly the same, and the time interval was made twice as
long, would the reported value be twice as large? The units of aerosol optical
depth do not suggest that it depends on the length of the time interval like,
for instance, precipitation amount does.

Best wishes

Jonathan
Received on Wed Jul 03 2013 - 08:51:45 BST