# [ncl-talk] RATIO in Taylor Diagram

Dennis Shea shea at ucar.edu
Mon Sep 21 08:21:04 MDT 2015

```  lat(lat)

x(time,lat,lon)

; x(0,:,:) ==> x(lat,lon)
wgt2d = conform(x(0,:,:), wgt, 0)

printVarSummary(wgt2d)

On Fri, Sep 18, 2015 at 2:04 PM, Vanúcia Schumacher
<vanucia-schumacher at hotmail.com> wrote:
> I'm confused on how to calculate weight,
> this way that I'm calculating the weight, it's has 3 dimensions
> what i doing wrong in this calculation? I understand that should have 2
> dimensions, but I can not do this.
>
> ; weight: commonly cosine(latitude)
>
>        lat     = f->lat
>
>
>
>       dims    = dimsizes(x)        ;[time][lat][lon]
>        ntim    = dims(0)
>        rank    = dimsizes(dims)
>
>        weight  = conform(x, wgt , rank-2)
>
>
>> Date: Thu, 17 Sep 2015 12:33:54 -0600
>> Subject: Re: [ncl-talk] RATIO in Taylor Diagram
>> From: shea at ucar.edu
>> To: vanucia-schumacher at hotmail.com
>> CC: ncl-talk at ucar.edu
>
>>
>>
>> ---
>>
>> Please do not send repeat questions to ncl-talk
>> All questions are flagged and will be answered. Many of us are on
>> travel or vacation.
>>
>> Good Luck
>> D,
>>
>>
>> On Mon, Sep 14, 2015 at 8:14 PM, Vanúcia Schumacher
>> <vanucia-schumacher at hotmail.com> wrote:
>> > Dear users,
>> >
>> > I'm confused with the calculation of RATIO (normalized root-mean-saquare
>> > (RMS) differences), relation to Taylor Diagram, the comments that I have
>> > read here in the group, it was suggested calculated in 3 ways:
>> >
>> > 1) Use of the function: dim_rmsd
>> >
>> > or
>> >
>> > 2) RATIO
>> > ; temporal variance at each grid point [local]
>> >
>> > ; vref_var_T = dim_variance_n(rdata, 0 ) ; (lat,lon)
>> > ; vcase_var_T = dim_variance_n(cdata, 0 )
>> >
>> > ; ; wgted areal *local* temporal variance
>> >
>> > ; wvar_ref_T = sum(wgt_S*vref_var_T)/sumwgt_S
>> > ; wvar_case_T = sum(wgt_S*vcase_var_T)/sumwgt_S
>> >
>> > ; sqrt of ratio of spatially weighted variances
>> >
>> > ; wvar_ratio_T = (wvar_case_T/wvar_ref_T)^0.5
>> >
>> > I did not understand what would that sumwgt_S ?
>> >
>> > or 3) more explicitly, for xc and xo on the same grid: wgtc=wgto
>> >
>> > ; wgtc = conform_dims(dimsizes(xc), gw, 0) ; make 2d for gw[*]
>> > ; xavgc = sum(wgtc*xc)/sum(wgtc) ; control centered
>> > mean
>> > ; xavgo = sum(wgtc*xo)/sum(wgtc)
>> >
>> > ; (b) compute the sum of the centered area weighted variances.
>> >
>> > ; dc2 = sum(wgtc*(xc-xavgc)^2) ; control ; centered
>> > ; do2 = sum(wgtc*(xo-xavgo)^2)
>> > ; rat = sqrt(do2/dc2)
>> >
>> > xc and xo is the variance or datasets?
>> >
>> >
>> > I would like to know the step by step to correct this calculation RATIO,
>> > if
>> > someone can help me, please.
>> >
>> > Thanks
>> >
>> >
>> >
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```