Seasonal data on a continuous time axis

[Mark Williams <mark.williams@xxxxxxxxxx>]

I am working quite a bit with seasonal data, for example the months DJF for 
OLR.
Each season is defined by, say,
let DJF9293 = olr[t=01-dec-1992:28-feb-1993]
let DJF9394 = olr[t=01-dec-1993:28-feb-1994]
let DJF9495 = olr[t=01-dec-1994:28-feb-1995]
from which means, variances etc can be readily worked out for each season.
If I then combine each season using the save/append command the newly 
created file will have each of the 3 seasons on a continuous time axis with 
nil data for the intermediate months (Mar till Nov each year).
If I then define a new variable using the transformations @ave or @var for 
the full 3 years ferret seems to weight the results according to the gaps 
in the data along the time axis.  What I want to do is to find a way of 
easily creating a file with the all the data along a continuous and equally 
spaced time axis so that @var etc will give the answers I am looking for.

If anyone can help it would be appreciated.

Thanks in advance.



Mark Williams
Monash CRC for Southern Hemisphere Meteorology
Victorian Regional office
Bureau of Meteorology
Melbourne
Australia