COBirders, The National Weather Service (NWS) really wanted to bury their radar products in a weird spot for now until they get all the radars updated to Dual-polarization. Here is the link I was passed by David Nicosia (Science and Operations Officer at Binghamton, NY NWS Office). Note these may break after a while depending on what the NWS decides to do with this page, but the data will still be flowing, we will just need to find the new page.
The first link goes directly to the "Digital Hydrometeor Classification" product for the Front Range radar (Denver, CO). http://www.srh.noaa.gov/ridge2/ridgenew2/?rid=FTG&pid=N0H The second link goes to the Grand Junction, CO radar (currently being upgraded, should be online by the end of the month). http://www.srh.noaa.gov/ridge2/ridgenew2/?rid=GJX&pid=N0H The third link goes to the Pueblo, CO radar (not yet upgraded). http://www.srh.noaa.gov/ridge2/ridgenew2/?rid=PUX&pid=N0H The legend on these imagery is not labeled well, so let me explain it a little. It is found on the right side of the image just outside of the map view. It goes from purple at the top to light gray at the bottom with the rainbow in between. Letters next to the legend stand for: RF = Range Folding UK = Unknown HA = Hail GR = Graupel BD = Big Drops HR = Heavy Rain RA = Rain WS = Wet Snow DS = Dry Snow IC = Ice Crystals GC = Ground Clutter/Anomalous Propagation BI = Biological Targets (Birds/Insects/Bats) The most important one for birders is arguably the BI (light gray) shading. One could argue that the most important is the actual precipitation, but we are birders not meteorologists (at the moment), so the birds are more important. Notice that the "Biological" color shading includes a lot of different things, not just birds. At times, it may even include dust particles and other particulate in the atmosphere like smoke or sand. The program that is doing the work to figure out these classifications isn't well trained yet, so there are bound to be plenty of times when the scheme is wrong. Earlier today, I saw "Big Drops" on the radar, and there wasn't even a cloud in the vicinity according to the visible satellite imagery (found on other pages). So read these imagery with a grain of salt. Within the "Biological" shading, you have to consider that there are more insects than birds than bats in this world, so a lot of the time in BI shading regions, you are seeing insects not birds, but it can be a mixture. Also, because a lot of birds are larger than 10 centimeters (approximately 4 inches; Broad-tailed, Black-chinned, and Rufous Hummingbird are approximately 4 inches long but have a wingspan from about 4.5 inches to 5.25 inches, so even they are "large" for a radar), they won't show up as well on radar imagery as objects smaller than 10 centimeters (approximately 4 inches; lots of insects). It's better to assume that you are looking at insects than birds (or bats) in most cases, or just be safer and call them biological targets. Overall this is a pretty cool product, but PLEASE use it with caution. There are a lot of assumptions that go into these equations, and some of these assumptions will be wrong most of the time, but they have no way of fixing these assumptions due to limited data. With practice and more synergy with other products, these can be refined to hopefully get us much closer to reality. Please don't be afraid to ask more questions about this if you have any. We are all still learning these products, so getting some different perspective may be just what you need. Bryan Guarente Instructional Designer/Meteorologist The COMET Program University Corporation for Atmospheric Research Boulder, CO -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
