1. Examples of spectral fields
Tornadic Spectra - May 8, 2003
Svetlana Bachmann
04/13/2005

2. The fields of spectral moments from data collected with the KOUN radar during a tornadic event (May 8, 2003) The fields of spectral moments re estimated using both time and frequency domain methods.
equivalent reflectivity factor (dBZ) mean Doppler velocity spectrum width
In Time Domain
In Frequency Domain

3. Region with the tornado
Spectra for azimuths from 24 to 34.
Y-axis shows range gate number (1 km = 4 range gates),
X-axis shows spectral coefficient number (zero velocity is in the center),
color-scale shows power in logarithmic units.
Tornado spectra are evident in radials 28.5, 29, 29.5, 30 at
~100th ranges gate (~ 25 km) Z v w
In non-tornadic regions spectra exhibit maxima
at the wind velocity. At the regions with ground
clutter spectra show two maxima at wind and at
zero-velocities. The width of the maxima are narrow.
At the tornado region spectra are multimodal and wide.

4. Azimuth 5 10 15 20 25 30 35
-35 35
Velocity
Range, km
Tornado