[ncl-talk] A request for data file and problem on "bw_bandpass_filter" function

[15295538792]

Dear NCL experts,

I'm writing to ask if you could send me the data file named "uwnd.day.850.anomalies.1980-2005.nc" which is used in the script "bfband_2.ncl". I can't find it in the online data files. In addition, I'd like to consult you about the function "bw_bandpass_filter" which applies a Butterworth bandpass filter to time series. The online documentation says that the cut-off paramaters ca and cb of this function should meet a condition of ca>cb (fcb>fca). However, when I exchanged the values of ca and cb, the results remained the same. How could this happen? In fact, I want to use this bandpass filter as a low pass filter which need only one cut-off frequency. So which parameter should I set to arbitrarily large (ca or cb)? Is there anything wrong in my script?  Please help. Thanking in anticipation. (PS: Input and output data files as well as ncl script I used has been attached to this email.)


Sincerely,
Shouli Xuan
Email:15295538792 at 163.com

2019-01-13


15295538792 
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