All,
 
I now have access to real-time dual polar radar imagery from NWS Pittsburgh 
from work.
Early this morning on 8/5/11, there was a modest migratory echo pattern around 
the
NWS Pittburgh radar. I have the legacy "base reflectivity"or  "Z"  images that
we are accustomed to. In these legacy images, you will see the typical 
blossoming
echo pattern at night that eventually diminishes after sunrise, with 
small "rings" appearing after sunset
which are likely larger birds taking off after sunrise from bodies of water. 
Then I have a new product 
"differential reflectivity"  or "ZDR" which is the log of the ratio of the 
returned power to the radar
in the horizontal plane vs the returned power in the vertical plane. For a 
raindrop, 
when it falls, it becomes flattened and its width is greater in the horizontal 
plane 
vs the vertical plane like a watermelon. In this case, the differential 
reflectivity 
will be larger than 1. For a sphere, like a hailstone, the ZDR is near zero.
A vertical oriented object will be less than zero.  See  
 
 http://www.cimms.ou.edu/~kscharf/pol/zdr.html
   
for more detailed info. 
 
Then I also include correlation coefficient (CC)which is a measure of how
similar the echoes are within the range bin of the radar. CC above
.97 is typically rain. Lower values indicate much more variability in the
sampled range bin. So in very basic terms, the higher the CC the more
similar the echoes are, the lower the values the more variability of the 
shapes of the radar echoes. For more info see...
 
http://www.cimms.ou.edu/~kscharf/pol/rhohv.html
 
All these images are uploaded to my flickr site since I don't have a website. 
In the next few days I will try to brainstorm some ideas as to what we may be 
seeing. 
This is all cutting edge and new. I also am not an expert on dual pol yet as I
am taking the NWS training classes now. So anyone who has ideas etc
feel free to chime in. We may stand to learn a lot. Will we be able to
detect passerine movements  vs.  waterfowl/larger bird movements with this 
data? 
Will the resolution be enough for such very general bird size determination? 
 
see below for the images:  
 
Base Reflectivity (legacy)  Z   
http://www.flickr.com/photos/davenicosia/sets/72157627241598335/
 
Differential Reflectivity  ZDR   
http://www.flickr.com/photos/davenicosia/sets/72157627365963798/
 
Correlation Coefficient CC   
http://www.flickr.com/photos/davenicosia/sets/72157627241652541/
 
 
More on this in the next few days...ideas welcome!!! 
 
Dave Nicosia
Johnson City, NY 
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