Re: [ferret_users] Calculating weights value in bandpass filtering using LANCZOS function in ferret

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi,
Did you search the email list archives? There are several discussions that look like they would be useful to you.

http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2008/msg00411.html

http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2011/msg00122.html

On 9/16/2015 9:29 PM, Masud OCN_DU wrote:

Dear ferret users,

I am new in ferret. I am using ferret function LANCZOS (filter), band-pass filter for analyzing a time series data for identifying more than 30 days and less than 150 days meso-scales variability. The data is weekly and I have 1045 values in the time axis.My study area is 80E:95E and 18N:23N in the northern Bay of Bengal.

I am not able to understand how ferret is selecting the weights. May I request for some needy help!!!
How to select correct weights in using the filter. Is my program OK? I would like to appreciate in advanced for helping me.

Ex :!for 30-150 days
USE weekly_ssh _data
plot ssh
let new_ssh = ssh[y=18N:23N@ave, x=80E:95E@ave] 
plot/over lanczos(new_ssh,0.05,0.25,91) 

I have some confusion  in understanding the function application.

Best regards,
Masud