climatological axes

[Francois Delclaux <francois.delclaux@xxxxxxxxxx>]

Hi, Ferret users,

May be someone could explain the climatology philisophy axis, because
I don't understand why ... I got the good results !

My starting point - and data -  is daily rainfall on 35 years on a point, each
year of 360 days.
And I want to get climatological years at daily, 10-day  and monthly scales.

Suppose p is my daily rainfall variable. (12600 values)

Concerning monthly scale, I first calculated monthly mean with the following
instruction :
yes ? let pm_reg=p[gt=month_reg@sum]

 For test, I calculated too the monthly mean values according irregular axis :
yes ? let pm_irreg=p[gt=month_irreg@sum]

Then I got two montly series , each of one whith 35x12=420 data, with no great
differences between them.
To get monthly climatological year, I use @MOD operation on climatological axes,

and here, too, I tested reg and ireg axes.

So I got 4 results :

yes ?  let pmc1=pm_reg[gt=month_reg@mod]
yes ?  let pmc2=pm_irreg[gt=month_reg@mod]
yes ?  let pmc3=pm_reg[gt=month_irreg@mod]
yes ?  let pmc4=pm_irreg[gt=month_irreg@mod]

At this point I found that pmc1 and pm_reg were identical data; same thing for
pmc4 and pm_irreg.
On the opposite,  pmc2 and pmc3 seem to be  good (and slightly different)
monthly
climatological years.

So my questions are :
- why could'not I use reg axes for computing  mean monthly values AND  monthly
climatological axes ?
- same question with ireg axes ?
- how can I do for daily and 10-day climatilogical axes ?

Waiting for answer

Bye

Francois DELCLAUX
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IRD  Hydrologie
BP 5045    34032 Montpellier Cedex           FRANCE
http://www.mpl.orstom.fr/~delclaux/
mailto: francois.delclaux@mpl.ird.fr
Tel : (33) (0)4-67-41-64-42     Fax : (33) (0)4-67-54-71-06
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