[ncl-talk] Coherence analysis

[Dennis Shea]

*http://www.ncl.ucar.edu/Applications/spec.shtml*
<http://www.ncl.ucar.edu/Applications/spec.shtml>
*Example: CrosSpc_TimeLon_1.ncl*

===
The datasets used were some you have.
The example illustrates the 'mechanics' of doing the freq vs longitude.


On Thu, Mar 21, 2019 at 3:56 AM Soma Roy <somaroy892 at gmail.com> wrote:

> Please kindly inform me..
>
> Soma
>
> On Wed, Mar 20, 2019, 22:45 Soma Roy <somaroy892 at gmail.com wrote:
>
>> I am trying with the attached script as you said. But getting constant
>> values..
>>
>> Summary of the input data along with intermediate steps are as follows;
>>
>> Variable: dslp
>> Type: double
>> Total Size: 93312000 bytes
>>             11664000 values
>> Number of Dimensions: 3
>> Dimensions and sizes:   [time | 45] x [lat | 360] x [lon | 720]
>> Coordinates:
>>             time: [25748..41819]
>>             lat: [-89.75..89.75]
>>             lon: [-179.75..179.75]
>> Number Of Attributes: 5
>>   long_name :   diurnal temperature range
>>   units :       degrees Celsius
>>   _FillValue :  9.969209968386869e+36
>>   missing_value :       9.969209968386869e+36
>>   correlation_decay_distance :   750
>>
>> Variable: dslp2
>> Type: double
>> Total Size: 259200 bytes
>>             32400 values
>> Number of Dimensions: 2
>> Dimensions and sizes:   [time | 45] x [lon | 720]
>> Coordinates:
>>             time: [25748..41819]
>>             lon: [-179.75..179.75]
>> Number Of Attributes: 6
>>   _FillValue :  9.969209968386869e+36
>>   long_name :   diurnal temperature range
>>   units :       degrees Celsius
>>   correlation_decay_distance :   750
>>   missing_value :       9.969209968386869e+36
>>   average_op_ncl :      dim_avg_n over dimension(s): lat
>>
>> Variable: tslp2
>> Type: double
>> Total Size: 259200 bytes
>>             32400 values
>> Number of Dimensions: 2
>> Dimensions and sizes:   [time | 45] x [lon | 720]
>> Coordinates:
>>             time: [25748..41819]
>>             lon: [-179.75..179.75]
>> Number Of Attributes: 6
>>   _FillValue :  9.969209968386869e+36
>>   long_name :   precipitation
>>   units :       mm/month
>>   correlation_decay_distance :   450
>>   missing_value :       9.969209968386869e+36
>>   average_op_ncl :      dim_avg_n over dimension(s): lat
>>
>> Variable: pr
>> Type: double
>> Total Size: 5760 bytes
>>             720 values
>> Number of Dimensions: 1
>> Dimensions and sizes:   [720]
>> Coordinates:
>> Number Of Attributes: 20
>>   yslope :      1e+36
>>   ylag1 :       1e+36
>>   yvaro :       1e+36
>>   yvari :       1e+36
>>   yavei :       1e+36
>>   xslope :      1e+36
>>   xlag1 :       1e+36
>>   xvaro :       1e+36
>>   xvari :       1e+36
>>   xavei :       1e+36
>>   coher_probability :   (    0,    0,    0,    0 )
>>   bw :  1e+36
>>   phase :       <ARRAY of 22 elements>
>>   coher :       <ARRAY of 22 elements>
>>   quspc :       <ARRAY of 22 elements>
>>   cospc :       <ARRAY of 22 elements>
>>   frq : <ARRAY of 22 elements>
>>   spcy :        <ARRAY of 22 elements>
>>   spcx :        <ARRAY of 22 elements>
>>   _FillValue :  9.969209968386869e+36
>>
>> Variable: h1
>> Type: double
>> Total Size: 176 bytes
>>             22 values
>> Number of Dimensions: 1
>> Dimensions and sizes:   [22]
>> Coordinates:
>>
>> Variable: h2
>> Type: double
>> Total Size: 176 bytes
>>             22 values
>> Number of Dimensions: 1
>> Dimensions and sizes:   [22]
>> Coordinates:
>>
>>
>> All values are constant like;
>>  yslope :      1e+36
>>   ylag1 :       1e+36
>>   yvaro :       1e+36
>>   yvari :       1e+36
>> and so on..
>>
>> Please let me know where I am doing wrong/missing something.
>>
>> Thanking you,
>> Soma
>>
>> On Wed, Mar 20, 2019 at 8:07 PM Soma Roy <somaroy892 at gmail.com> wrote:
>>
>>> Can you kindly give me a hint how to use the function over a variable
>>> (say 3D variable as time, lat, lon) as you said?
>>>
>>> Thanking you,
>>> Soma
>>>
>>> On Wed, Mar 20, 2019, 20:00 Dennis Shea <shea at ucar.edu wrote:
>>>
>>>> For sure, these were created with NCL. However, I am not sure how these
>>>> were created.
>>>>
>>>> NCL's *specxy_anal*
>>>> <http://www.ncl.ucar.edu/Document/Functions/Built-in/specxy_anal.shtml>
>>>>
>>>> could have been applied *at each longitude* (loop over longitudes) and
>>>> the results stored in arrays:
>>>>
>>>>    COHER(frq,lon), PHASE(frq,lon), COSPC(frq,lon),  QUSPC(frq,lon)
>>>>
>>>> ===
>>>> Other, possibly useful, links:
>>>>
>>>> *http://www.ncl.ucar.edu/Applications/space_time.shtml*
>>>> <http://www.ncl.ucar.edu/Applications/space_time.shtml>
>>>>
>>>> *http://www.ncl.ucar.edu/Applications/mjoclivar.shtml*
>>>> <http://www.ncl.ucar.edu/Applications/mjoclivar.shtml>
>>>> *Example 11*
>>>> ====
>>>>
>>>> Good luck
>>>>
>>>> On Wed, Mar 20, 2019 at 2:42 AM Soma Roy <somaroy892 at gmail.com> wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> I am trying to calculate Coherence, Cospectrum, Quadrature and phase
>>>>> between two variables (two signals).
>>>>>
>>>>> Is there any function available in ncl to plot like below attached
>>>>> figure for the above?
>>>>>
>>>>> Please kindly inform me.
>>>>>
>>>>> Thanking you,
>>>>> Soma
>>>>> _______________________________________________
>>>>> ncl-talk mailing list
>>>>> ncl-talk at ucar.edu
>>>>> List instructions, subscriber options, unsubscribe:
>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>
>>>>
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