<font size="2"><span style="background-color:rgba(255,255,255,0)">Hi Maria,</span></font><div><font size="2"><span style="background-color:rgba(255,255,255,0)"><br></span></font></div><div><font size="2"><span style="background-color:rgba(255,255,255,0)">Yes, i actually want to analyze 16-day planetary waves (k=1) waves using daily data. But in this case, i dont need to decompose it into eastward and westward propgating waves. I tried to bandpass filter the data, but since the frequency bands are too narrow (1/15) and (1/17).. the results are bad. any suggestion? does it mean that i need higher temporal resolution?</span></font></div><font size="2"><span style="background-color:rgba(255,255,255,0)">the steps that i do are:</span></font><div><font size="2"><span style="background-color:rgba(255,255,255,0)">1. filter data using forward and backward fourier to retain k=1</span></font></div><div><font size="2"><span style="background-color:rgba(255,255,255,0)">2. bandpass this filtered data to retain only freq at 1/16day</span></font></div><div><font size="2"><span style="background-color:rgba(255,255,255,0)"><br></span></font></div><div><font size="2"><span style="background-color:rgba(255,255,255,0)">Chang<br></span></font><div><font size="2"><span style="background-color:rgba(255,255,255,0)"><br><br>On Tuesday, 6 October 2015, Maria Gehne - NOAA Affiliate <<a href="mailto:maria.gehne@noaa.gov">maria.gehne@noaa.gov</a>> wrote:<br></span></font><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><font size="2"><span style="background-color:rgba(255,255,255,0)">Can you explain in more detail what you are trying to do? Are you trying to only look at phenomena that have a period of 16 days?</span></font><div><font size="2"><span style="background-color:rgba(255,255,255,0)"><br></span></font></div><div><font size="2"><span style="background-color:rgba(255,255,255,0)">Maria</span></font></div></div><div class="gmail_extra"><font size="2"><span style="background-color:rgba(255,255,255,0)"><br></span></font><div class="gmail_quote"><font size="2"><span style="background-color:rgba(255,255,255,0)">On Tue, Oct 6, 2015 at 12:31 AM, Xi Chang <span dir="ltr"><<a target="_blank">xi.chang01@gmail.com</a>></span> wrote:<br></span></font><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><font size="2"><span style="background-color:rgba(255,255,255,0)">Thanks for the reply. No i dont use it, since what i need is how to extract/filter the daily data having frequency 1/16 day. is it possible to only use bandpass filter?</span></font><div><div><font size="2"><span style="background-color:rgba(255,255,255,0)"><br></span></font></div><div><font size="2"><span style="background-color:rgba(255,255,255,0)"><br></span></font></div><div><font size="2"><span style="background-color:rgba(255,255,255,0)"><br><br>On Tuesday, 6 October 2015, Dennis Shea <<a target="_blank">shea@ucar.edu</a>> wrote:<br></span></font><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><font size="2"><span style="background-color:rgba(255,255,255,0)">Are you looking a 'complex demodulation" ???<br><br>If so, that is in the 6.3.1 release:<br> <a href="http://www.ncl.ucar.edu/future_release.shtml" target="_blank">http://www.ncl.ucar.edu/future_release.shtml</a><br><br>Click 'demod_cmplx' =><br><a href="http://www.ncl.ucar.edu/Document/Functions/Contributed/demod_cmplx.shtml" target="_blank">http://www.ncl.ucar.edu/Document/Functions/Contributed/demod_cmplx.shtml</a><br><br>See Examples at the bottom of <a href="http://www.ncl.ucar.edu/Applications/spec.shtml" target="_blank">http://www.ncl.ucar.edu/Applications/spec.shtml</a><br><br><br>On Mon, Oct 5, 2015 at 4:32 PM, Xi Chang <<a>xi.chang01@gmail.com</a>> wrote:<br>> Hi NCL,<br>><br>> I have daily data 10 years. I'd like to filter the data at frequency (1/16)<br>> day. To do so what the most appropiate frquency ranges that i have to use<br>> ?, is it domething like fa=1/15 and fb=1/17 ?<br>> I aware if the band is too narrow the filtered signals are fake /artificial<br>> (i tesed with ncl butterwooth and the filtered results are weird) ? is there<br>> any idea how to do that appropriately? do i need to use hourly data instead<br>> of daily?<br>><br>> Thanks<br>><br>> _______________________________________________<br>> ncl-talk mailing list<br>> <a>ncl-talk@ucar.edu</a><br>> List instructions, subscriber options, unsubscribe:<br>> <a href="http://mailman.ucar.edu/mailman/listinfo/ncl-talk" target="_blank">http://mailman.ucar.edu/mailman/listinfo/ncl-talk</a><br>><br></span></font></blockquote></div></div><font size="2"><span style="background-color:rgba(255,255,255,0)"><br>_______________________________________________<br>ncl-talk mailing list<br><a target="_blank">ncl-talk@ucar.edu</a><br>List instructions, subscriber options, unsubscribe:<br><a href="http://mailman.ucar.edu/mailman/listinfo/ncl-talk" rel="noreferrer" target="_blank">http://mailman.ucar.edu/mailman/listinfo/ncl-talk</a><br></span></font><br></blockquote></div></div></blockquote></div></div><br>On Tuesday, 6 October 2015, Maria Gehne - NOAA Affiliate <<a href="mailto:maria.gehne@noaa.gov">maria.gehne@noaa.gov</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Can you explain in more detail what you are trying to do? Are you trying to only look at phenomena that have a period of 16 days?<div><br></div><div>Maria</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 6, 2015 at 12:31 AM, Xi Chang <span dir="ltr"><<a href="javascript:_e(%7B%7D,'cvml','xi.chang01@gmail.com');" target="_blank">xi.chang01@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thanks for the reply. No i dont use it, since what i need is how to extract/filter the daily data having frequency 1/16 day. is it possible to only use bandpass filter?<div><div><div><br></div><div><br></div><div><br><br>On Tuesday, 6 October 2015, Dennis Shea <<a href="javascript:_e(%7B%7D,'cvml','shea@ucar.edu');" target="_blank">shea@ucar.edu</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Are you looking a 'complex demodulation" ???<br>
<br>
If so, that is in the 6.3.1 release:<br>
<a href="http://www.ncl.ucar.edu/future_release.shtml" target="_blank">http://www.ncl.ucar.edu/future_release.shtml</a><br>
<br>
Click 'demod_cmplx' =><br>
<a href="http://www.ncl.ucar.edu/Document/Functions/Contributed/demod_cmplx.shtml" target="_blank">http://www.ncl.ucar.edu/Document/Functions/Contributed/demod_cmplx.shtml</a><br>
<br>
See Examples at the bottom of <a href="http://www.ncl.ucar.edu/Applications/spec.shtml" target="_blank">http://www.ncl.ucar.edu/Applications/spec.shtml</a><br>
<br>
<br>
On Mon, Oct 5, 2015 at 4:32 PM, Xi Chang <<a>xi.chang01@gmail.com</a>> wrote:<br>
> Hi NCL,<br>
><br>
> I have daily data 10 years. I'd like to filter the data at frequency (1/16)<br>
> day. To do so what the most appropiate frquency ranges that i have to use<br>
> ?, is it domething like fa=1/15 and fb=1/17 ?<br>
> I aware if the band is too narrow the filtered signals are fake /artificial<br>
> (i tesed with ncl butterwooth and the filtered results are weird) ? is there<br>
> any idea how to do that appropriately? do i need to use hourly data instead<br>
> of daily?<br>
><br>
> Thanks<br>
><br>
> _______________________________________________<br>
> ncl-talk mailing list<br>
> <a>ncl-talk@ucar.edu</a><br>
> List instructions, subscriber options, unsubscribe:<br>
> <a href="http://mailman.ucar.edu/mailman/listinfo/ncl-talk" target="_blank">http://mailman.ucar.edu/mailman/listinfo/ncl-talk</a><br>
><br>
</blockquote></div>
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</blockquote>