Differential Reflectivity
- Raindrops are not always spherical
when they fall - especially the larger drops
- They tend to become more oblate
-->>
- So, the reflectivity would be
larger if the wave were horizontally polarized,
or Zh
> Zv
- Define ZDR =
differential reflectivity = 10 log (Zh/Zv)
- ZDR is great for
discriminating large drops from hail - hail
tumbles randomly, looks like a spherical
particle.
- Here
are typical ZDR values for different
sized rain drops
- So, ZDR for hail is
about 0.
- ZDR for ice is about 0
as well.
ZDR example for a summertime
thunderstorm:
Combining
ZDR and other multi-parameter variables with dBZe can tell us much about
the internal microphysical structure of storms
REQUIRED MATERIAL: 4. Dual-Pol Radar Products
at:
http://www.wdtb.noaa.gov/courses/dualpol/index.html |