Re: [ferret_users] monthly abnormal

Hi Xia,
The topic to look up in the documentation is "anomaly". I think the best place to start would be this FAQ:
How do I calculate climatologies and climatological anomalies?
or if you search the archives of the Users List for "anomaly" or "anomalies" you will find more discussion.

Ansley

Changshui Xia wrote:

Dear all,

I have a model monthly mean temperature ouput from 1980~2007 stored in one netcdf file.I want to get the monthly abnormal(that is every Jan temperature minus the average value of all Jan temperature from 1980-2007 )

How to achieve it using ferret?

This is the content of the file

netcdf np908_monthly_sst {
dimensions:
        time = UNLIMITED ; // (336 currently)
        lat = 301 ;
        lon = 307 ;
variables:
        float lat(lat) ;
                lat:units = "degrees_north" ;
        float lon(lon) ;
                lon:units = "degrees_east" ;
        float time(time) ;
                time:units = "months since 1980-01-01 00:00:00" ;
                time:time_origin = "01-jan-1980 00:00:00" ;
                time:modulo = " " ;
        float sst(time, lat, lon) ;
                sst:missing_value = 32767.f ;
data:
.................

Thank you in advance.

Xia