Re: How to extract equatorial waves by filtering in thewheeler-kiladis wavenumber-frequency domain.

From: Carl J. Schreck, III <carl_at_nyahnyahspammersnyahnyah>
Date: Tue Jan 26 2010 - 07:41:27 MST

Thanks for catching the typo in the documentation. You are correct, it
should read "pos (eastward) or neg (westward)". For ER or MRG waves, for
example, kMax = -1 and kMin = -10.

Let me know if you run into other issues.

     Carl

On Mon, Jan 25, 2010 at 9:33 PM, HUANG, Ping <ph0007@ustc.edu> wrote:

> Hi Carl,
>
> Thanks for your scripts!
>
> There is a question about the wavenumber setting. As we know, the positive
> wavenumber indicate the eastward propagating wave while negative wavenumber
> indicate westward propagating wave. And in your sample script for
> filtering kelvin waves, the eastward propagating wave, the* positive *wavenumber
> are used. However, in the usage of kf_filter.ncl the wavenumber parameters
> *kmin* and *kmax* are described as "*
> kMin, kMax: range of wavenumbers, can be pos (westward) or neg (eastward)*". I am a little confused about that.
>
> Huang Ping
>
> ------------------------------
> *发件人:* Carl J. Schreck, III
> *发送时间:* 2010-01-26 02:13:48
> *收件人:* HUANG, Ping
> *抄送:* ncl-talk
> *主题:* Re: [ncl-talk] How to extract equatorial waves by filtering in
> thewheeler-kiladis wavenumber-frequency domain.
> I'm not sure if there is anything built into ncl to do this. However,
> I've written a function that does it. The function is in the attached file
> kf_filter.ncl. Also attached is a sample program, spacetime.ncl, that uses
> this filter to filter for Kelvin waves. You can change the parameters to
> filter for other waves.
>
> Hope this helps.
>
> Carl
>
>
> On Mon, Jan 25, 2010 at 11:51 AM, HUANG, Ping <ph0007@ustc.edu> wrote:
>
>> Hi all
>>
>> I want to extract equatorial waves by filtering in the wheeler-kiladis
>> wavenumber-frequency domain. By function "wkSpaceTime", the wavenumber
>> frequency spectra can be calculated and plotted. Is there a function or
>> sample script for extracting equatorial waves based on the wheeler-kiladis
>> space-time spectra?
>>
>> Thanks.
>>
>> Huang Ping
>>
>>
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>
>
>
> --
> Carl J. Schreck, III
> PhD Student
> Department of Atmospheric and Environmental Sciences
> University at Albany, ES 330
> carl@atmos.albany.edu
> http://www.atmos.albany.edu/student/carl/
>

-- 
Carl J. Schreck, III
PhD Student
Department of Atmospheric and Environmental Sciences
University at Albany, ES 330
carl@atmos.albany.edu
http://www.atmos.albany.edu/student/carl/

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Received on Tue Jan 26 07:41:55 2010

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