[ncl-talk] How to plot t-test figure, involve multiinput file?

[Mary Haley]

Please see example "climo_1.ncl" at:

http://www.ncl.ucar.edu/Applications/climo.shtml

I admittedly don't know much about ttest, but this example uses it in a way
that sounds similar to your request.

--Mary


On Tue, Nov 3, 2015 at 7:54 PM, Steven Kong <kongksk at gmail.com> wrote:

> Hi all,
>
> I would like to plot t-test figure, between the average of future and the
> average of the present periods. Both period consist of 2 continuous days as
> follow:
>
> Future: 01 to 02 January 2100
> Present: 01 to 02 Janaury 2010
>
> Could anyone help me on this? Your help is highly appreciated.
>
>
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;script;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
>
> begin
>    a1 = addfile("./JAN2100/01-05/wrfout_d02_2100-01-01_00:00:00","r")
>    a2 = addfile("./JAN2100/01-05/wrfout_d02_2100-01-02_00:00:00","r")
>
>    b1 = addfile("./JAN2010/01-05/wrfout_d02_2010-01-01_00:00:00","r")
>    b2 = addfile("./JAN2010/01-05/wrfout_d02_2010-01-02_00:00:00","r")
>
>   wks = gsn_open_wks("x11","T-test1-90%")
>         gsn_define_colormap(wks,"BlAqGrYeOrReVi200")            ; Create a
> plot workstation
>
>   opts = True                                      ; Set some Basic Plot
> options
>   opts at MainTitle = "GEOGRID FIELDS"
>   opts at InitTime = False                            ; Do not plot time or
> footers
>   opts at Footer = False
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;Get the
> Variables;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
> tempa1 = a1->T2
> tempa2 = a2->T2
>
> tempb1 = b1->T2
> tempb2 = b2->T2
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;Calculate average and variance for
> Future;;;;;;;;;;;;;;;;;;;;
>
> aveX1 = dim_avg_n_Wrap(tempa1,0)  ; average over the 0th dim
> varX1 = dim_variance_n_Wrap(tempa1,0) ; compute variance
>
> aveX2 = dim_avg_n_Wrap(tempa2,0)  ; average over the 0th dim
> varX2 = dim_variance_n_Wrap(tempa2,0) ; compute variance
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;Calculate average and variance for
> Present;;;;;;;;;;;;;;;;;;;;
>
> aveY1 = dim_avg_n_Wrap(tempb1,0)  ; average over the 0th dim
> varY1 = dim_variance_n_Wrap(tempb1,0) ; compute variance
>
> aveY2 = dim_avg_n_Wrap(tempb2,0)  ; average over the 0th dim
> varY2 = dim_variance_n_Wrap(tempb2,0) ; compute variance
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;Do T-Test for 1st day and 2nd
> day;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
> alphat1 = 100.*(1. - ttest(aveX1,varX1,24, aveY1,varY1,24, True, False))
> aveX1 = where(alphat1.lt.90.,aveX1 at _FillValue, aveX1)
>
> alphat2 = 100.*(1. - ttest(aveX2,varX2,24, aveY2,varY2,24, True, False))
> aveX2 = where(alphat2.lt.90.,aveX2 at _FillValue, aveX2)
>
> ;;;;;;;;;;;;;;;;;;;;;;;;;;Do T-Test for the average of 1st and 2nd
> days;;;;;;;;;;;;;;;;;;
>
> result = (alphat1 + alphat2)/2
> ;result = (aveX1 + aveX2)/2
>
>
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