Weather Radar, Winds, and Migration
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Bryan Guarente
Sep 22, 2012, 11:33:48 PM9/22/12
to Cobirds
COBirders,
For those that were interested the other night, tonight is another great example of bird migration on radar. Take a look at this image: http://weather.rap.ucar.edu/radar/displayRad.php?icao=KUSA&prod=bref1&bkgr=black&endDate=20120923&endTime=3&duration=0
It is pretty obvious where the birds would "want" to be migrating and where they wouldn't based on the winds. If you want to find the national radar image on other dates, you can find it here:
http://weather.rap.ucar.edu/radar/
To find the winds and predicted winds, you can go to this website:
http://homes.comet.ucar.edu/~guarente/birdweather/stream.htm
Good luck with these tonight, and have fun. There may be a quiz in a day or two about where the radars should be lighting up based solely on the winds. Keep your eyes peeled.
For those that were interested the other night, tonight is another great example of bird migration on radar. Take a look at this image: http://weather.rap.ucar.edu/radar/displayRad.php?icao=KUSA&prod=bref1&bkgr=black&endDate=20120923&endTime=3&duration=0
That
is an archived image from 9pm Saturday night. I know these rings around each radar are likely birds/insects/bats (70% probability) based on previous experience with radar meteorology. There are other things going on here that will affect the radar echoes, so not ALL of these echoes are birds/insects/bats (note the probability above). If you want to look at the most recent US radar view (no matter when you click this link), you can click here:
To get a different understanding of this, you can check the local wind flows at migration levels (approximately 1-2 km above ground; 900-850mb
[pressure-levels]). You will notice the winds are flowing to the southeast where most of the birds are showing up on radar. This is a good wind direction to get migration. Notice that the winds in Colorado are not really conducive for migration. Sure, some birds will be moving on these winds because they are too bad, but they could be better.
Here is the wind imagery to compare to the first radar image linked above:
If you read this email before 11pm Saturday, look at this image:
http://www.atmos.illinois.edu/~bguaren2/birdweather/nam_stream_900_12.gif
If you read this email after 11pm Saturday, you will likely need to look at this image:
http://www.atmos.illinois.edu/~bguaren2/birdweather/nam_stream_900_00.gif
Here is the wind imagery to compare to the first radar image linked above:
If you read this email before 11pm Saturday, look at this image:
http://www.atmos.illinois.edu/~bguaren2/birdweather/nam_stream_900_12.gif
If you read this email after 11pm Saturday, you will likely need to look at this image:
http://www.atmos.illinois.edu/~bguaren2/birdweather/nam_stream_900_00.gif
It is pretty obvious where the birds would "want" to be migrating and where they wouldn't based on the winds. If you want to find the national radar image on other dates, you can find it here:
http://weather.rap.ucar.edu/radar/
To find the winds and predicted winds, you can go to this website:
http://homes.comet.ucar.edu/~guarente/birdweather/stream.htm
Good luck with these tonight, and have fun. There may be a quiz in a day or two about where the radars should be lighting up based solely on the winds. Keep your eyes peeled.
Bryan Guarente
Instructional Designer/Meteorologist
The COMET Program
University Corporation for Atmospheric Research
Boulder, CO
P.S. I have an email out to some National Weather Service contacts about finding the dual-polarization radar imagery online if possible. I will likely hear back by Monday night. If there is any luck with imagery on the web, I will make sure to post to the list with the links.
Instructional Designer/Meteorologist
The COMET Program
University Corporation for Atmospheric Research
Boulder, CO
P.S. I have an email out to some National Weather Service contacts about finding the dual-polarization radar imagery online if possible. I will likely hear back by Monday night. If there is any luck with imagery on the web, I will make sure to post to the list with the links.
Bryan Guarente
Sep 23, 2012, 11:23:46 PM9/23/12
to Cobirds
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.
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.
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