Re: [ferret_users] monthly averages

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi Steve,
Yes, exactly right. The only wrinkle in modulo regridding is noted in the Users Guide: This is described several paragraphs down in Ch4 Sec 2.5 Modulo Regridding 

"Unlike other transformations and regridding, modulo regridding is performed as an unweighted average: each non-missing source point contributes 100% of its weight to the destination grid box within which it falls. If the source and destination axes are not properly aligned this can lead to apparent shifts in the data. ... "

the section goes on to show how to correct for this.  It'd be particularly apparent if your data were, for instance at the start of each month, as the month_reg and month_irreg modulo axes are defined with their coordinate values at the middle of each month.

Ansley

Steve Knox wrote:

Hi,
I have month max temp data for 100 years.
name     title                                                    I         J         K         L
TMX      Maximum temperature              1:720     1:360     ...       1:1200

If I want to plot the *100 year average* for each month, is the following correct, or am I missing something?

use "tmx.nc"
use climatological_axes
cancel data climatological_axes
let p1=tmx[gt=month_reg@mod]
shade p1[l=1]
shade p1[l=2]
...
shade p1[l=12]

Thanks!

Steve