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

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/

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Received on Mon Jan 25 19:34:19 2010