I am using Amaseis to record infrasound data
(sound below 20 Hz) and I would like to plot
my data to display dopper shifts.

My infrasound receiver is a few miles from
the Pentagon and I seem to be in the flight
path between the Pentagon and Quantico.
Every day I pick up helicopter noise in the
10 to 20 Hz band.  There seems to be
a nice dopper shift that I have not figured
out how to display with seismic software.

Here is a typical SAC data file from a
helicopter overflight this morning:
http://www.infiltec.com/seismo/090618heli1.sac 
The fundamental shifts from ~12.5 Hz as it 
approaches, to ~9.5 Hz as it leaves.

Can anyone suggest software to plot this data
to display the dopper shift?  Perhaps a stacked
3D spectra-time plot, or a 2D waterfall of 
frequency vs time?  Of course I can generate
any of the Amaseis file formats or any of the
WinQuake formats as program inputs.

Thanks

Dave
http://www.infiltec.com/Infrasound@home

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