# Re: monthly mean climatology

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Tue Jan 22 2013 - 18:22:28 MST

There are several approaches

[2] there is an unsupported and undocumented function in
contributed.ncl: calculate_monthly_values

It requires a time coordinate variable associated
with the input variable 'x'. This time coordinate
variable must be udunits compatible:

"days since ...", "hours since ...", "seconds since ..."

See cd_calendar and cd_inv_calendar

;---------------------------------
; undocumented and unsupported
;---------------------------------
undef ("calculate_monthly_values")
function calculate_monthly_values (x:numeric, arith:string,
nDim[1]:integer, opt[1]:logical)

; calculate monthly values [avg, sum, min, max]
; x: numeric array of 5D or less [eg: time,lev,lat,lon]
; *must* have time coordinate recognized by cd_calendar
; if 5D [case,time,lev,lat,lon]
; arith: "avg" [also, "ave"], "sum","min","max" others may be added
later
; nDim : scalar integer that specifies the 'time' dimension [generally, 0]
; opt : option ... not used here
;
; Sample usage: x(time,lat,lon) where time are n-hrly or daily values.
; xMonthAvg = calculate_monthly_values(x, "avg", 0, False)
; xMonthSum = calculate_monthly_values(x, "sum", 0, False)
; xMonthMin = calculate_monthly_values(x, "min", 0, False)
; xMonthMax = calculate_monthly_values(x, "max", 0, False)
;
; It is assumed that there will be multiple elements for the dim_avg_n
; calculation.
;

On 1/22/13 4:32 PM, Xi Chang wrote:
> Hallo NCL users,
>
> does anyone has a trick how to calculate monthly mean climatology from
> daily dataset?
>
> Thank you for the help.
>
>
>
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Received on Tue Jan 22 18:22:44 2013

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