# Re: Taylor Diagram

From: I N <qphoton_at_nyahnyahspammersnyahnyah>
Date: Tue Nov 15 2011 - 10:05:26 MST

Dear Dennis,

I suppose xbar is overall mean of the field (over space and time). The
"Taylor Diagram Primer" says:
In the case of a time varying field, the sum (summation in formulas)
is a double-sum computed over all grid cells and all time samples.
That means, it is possible to use daily data but I am not sure.

Regards
Nadeem

On Tue, Nov 15, 2011 at 5:40 PM, Dennis Shea <shea@ucar.edu> wrote:
> The 'problem' with daily data is that it can be very noisy.
> I am not aware of any use of Taylor diagrams with daily data.
>
>
> The Taylor diagram requires [1] a pattern correlation.
> [2] computation of variances ... this requires (x(i)-xbar)^2
>    What to use for xbar?
>
>
>
>
>
> On 11/15/11 9:31 AM, I N wrote:
>>
>> Dear Dennis,
>>
>>   Thanks for the quick reply.  My first question was not actually
>> about reference grid rather it was about temporal resolution of the
>> data.
>> It is recommended to use monthly/seasonal data or one can also use
>> daily data for taylor diagram?
>>
>> Regards
>> Nadeem
>>
>>
>> On Tue, Nov 15, 2011 at 5:01 PM, Dennis Shea<shea@ucar.edu>  wrote:
>>>
>>> [1] You can use any reference grid. As to what is appropriate for
>>>    one year of daily data, I don't know. You have to make that
>>>    decision.
>>>
>>> [2] for only an 8 degree latitude span, the results will be
>>>    more or less the same. Again, you shuld make that choice.
>>>
>>> Good luck
>>>
>>> On 11/15/11 8:37 AM, I N wrote:
>>>>
>>>> Dear All,
>>>> I have a one year daily precipitation data from different setups of
>>>> the same RCMl and observed precipication, all on the same curvilinear
>>>> grid (Lambert conformal projection).
>>>> The task is to create taylor diagram for whole year, Winter, Summer
>>>> and 4 seasons (DJF,MAM,....).
>>>> The latitude span of domain is from 42N to 50N (8 degree)
>>>>
>>>> I have few questions:
>>>>
>>>> 1) From NCL website, second line on the page "Special Topics: Taylor
>>>> Diagrams"
>>>>
>>>>  "The plotted values are generally derived from monthly or seasonal
>>>> climatological means of one or more variables"
>>>>
>>>> This means that it is recommended to use monthly/seasonal climatology.
>>>> Does it apply to all cases or in my case (only 1 year of data)
>>>> I can use daily data. What is advantage/disadvantage of using daily
>>>> data?
>>>>
>>>>
>>>> 2) From ncl-talk archive of May 21, 2010.
>>>>
>>>>>> If the region being tested is 'large' then a weight variable [wgt]
>>>>>> should be created. If your region is 'small', you can ignore the
>>>>>> weight [wgt=1]. Given that you are looking at a very small area, you
>>>>>> can ignore any weighting. Also you have masked out all points outside
>>>>>> your area of interest.
>>>>
>>>> Small and large are relative terms!! If the latitude span is 8 degree,
>>>> it is considered small or not?
>>>> I find significant differences between wgt=1 and
>>>> wgt=cos(lat2d*0.01745329) versions of taylor diagram.
>>>>
>>>> Thanks in advance
>>>> Regards
>>>> Nadeem
>>>> _______________________________________________
>>>> ncl-talk mailing list
>>>> List instructions, subscriber options, unsubscribe:
>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>
>
_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk
Received on Tue Nov 15 10:05:43 2011

This archive was generated by hypermail 2.1.8 : Thu Nov 17 2011 - 11:50:12 MST