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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