radar

Let'sgoflying!

Let'sgoflying!

Touchdown! Greaser!
Joined
Feb 23, 2005
Messages
20,315
Location
west Texas
Display Name
Display name:
Dave Taylor
http://www.srh.noaa.gov/radar/loop/DS.p19r0/si.kmaf.shtml

if you get this in the next hour, check out the radar image...
Ive seen it just like this before, with a huge reflection in an ever expanding pattern, seemingly centered on the radar site. If you click long range, composite, loop, (edit - all of the loops do it), it looks like a nuclear explosion in progress.
The metars for that site are benign (clr)
What the heck is it?
 
I've seen similar returns on documentaries about bats. IIRC, there is a HUGE colony in Texas somewhere.
 
Let'sgoflying! said:
http://www.srh.noaa.gov/radar/loop/DS.p19r0/si.kmaf.shtml

if you get this in the next hour, check out the radar image...
Ive seen it just like this before, with a huge reflection in an ever expanding pattern, seemingly centered on the radar site. If you click long range, composite, loop, (edit - all of the loops do it), it looks like a nuclear explosion in progress.
The metars for that site are benign (clr)
What the heck is it?
Click to expand...

Dust maybe? You getting winds out that way tonight? It's high reflectivity... I usually see it off the Del Rio site, occasionally from New Braunfels.
 
Brian Austin said:
I've seen similar returns on documentaries about bats. IIRC, there is a HUGE colony in Texas somewhere.
Click to expand...

BA, the bats are down my way. Bracken Cave, which is between New Braunfels and San Antonio. ATC can see them on radar - one night they were allowing deviations for traffic into SAT because the bat cave (doodoodoodoo doodoodoodooo - Bat Man) is just off the MARCS7 arrival - and they were headed towards the arrival.
 
AdamZ said:
Wow! Kaboom! What are those lines shooting in from the East and West?
Click to expand...

East west lines are *big* reflections close to the site affecting one major radial. Airplane, maybe?
 
wsuffa said:
BA, the bats are down my way. Bracken Cave, which is between New Braunfels and San Antonio. ATC can see them on radar - one night they were allowing deviations for traffic into SAT because the bat cave (doodoodoodoo doodoodoodooo - Bat Man) is just off the MARCS7 arrival - and they were headed towards the arrival.
Click to expand...
How high do bats fly?
 
I don't think it would be bats in this case Toby because of the display (range, altitude, volume) but how high do they fly? -- I have never seen bats higher than the 'mosquito layer' although at least some species do migrate so maybe they can go higher.
 
I know of one instance of a bat hitting a T-37-B at 8,000 feet. Higher than I would have guessed.

I believe you are seeing the "clear air mode" of the doppler radar. In this mode the radar is set to its most sensitive and gets lots of echos from dust, etc..

S.
 
Last edited:
Clear air mode, OK.

PS - There wasn't a lot of dust - winds were light all evening:

KMAF 140653Z AUTO 12008KT 10SM CLR 13/M01 A3009 RMK AO2 SLP155 T01331006
KMAF 140553Z AUTO 13006KT 10SM CLR 14/M01 A3009 RMK AO2 SLP154 T01441011 10250 20144 402670028 53003
KMAF 140453Z 12008KT 10SM CLR 16/M02 A3008 RMK AO2 SLP149 T01611017
KMAF 140353Z 12008KT 10SM CLR 17/M02 A3008 RMK AO2 SLP153 T01671022
KMAF 140253Z 11009KT 10SM CLR 18/M02 A3008 RMK AO2 SLP152 T01781017 53010
KMAF 140153Z 10007KT 10SM CLR 18/M01 A3006 RMK AO2 SLP152 T01781011
KMAF 140053Z 10007KT 10SM CLR 23/M02 A3005 RMK AO2 SLP151 T02281022
KMAF 132353Z 11009KT 10SM CLR 25/M05 A3005 RMK AO2 SLP148 T02501050 10267 20239 55003
KMAF 132253Z 10007KT 10SM CLR
 
Dust most likely....I have also heard of this when certain conditions are right(particulate, temp, mositure...) this happens at sunrise and sunset for some reason...at least thats what some radar controllers have told me.
 
According to these articles, they fly as high as 10,000 feet:

http://research.utk.edu/ora/rag/goodnews/1997/08-13.html

http://www.tpwd.state.tx.us/nature/wild/vertebrate/mammals/bats/natcropdusters.htm

Talk about a rude awakening on a night flight! We have a fairly large population around the Austin area. If you are ever in Austin (or central Texas) in the spring and summer, you have to visit one of the caves nearby at dusk, or be anywhere near Congress street bridge at dusk. It's an amazing sight to see thousands of those things emerge from under the bridge and take flight.
 
Toby said:
How high do bats fly?
Click to expand...
The bats in this documentary were up as high as 12K according to radar return (which I suspect is the Bracken Cave Bill mentioned). There are millions of bats in that cave system. It takes HOURS just for them to get out and into the caves.
 
Do they coordinate with ground for taxi and departure for takeoff?
 
gkainz said:
Do they coordinate with ground for taxi and departure for takeoff?
Click to expand...
Actually, it's flippin' weird how they do this. It does seem coordinated in some way. Imagine millions of flying objects, all aiming for the same exits/entrances at the same time, flying within inches of each other!
 
Brian Austin said:
Imagine millions of flying objects, all aiming for the same exits/entrances at the same time, flying within inches of each other!
Click to expand...
Pretty much like my morning commute into the dark heart of downtown Denver every morning! :eek: :dance:
 
gkainz said:
Pretty much like my morning commute into the dark heart of downtown Denver every morning! :eek: :dance:
Click to expand...
I'll take just about any big city in the US over Southern California. You can't pay me enough money to live in that state.
 
Brian Austin said:
I'll take just about any big city in the US over Southern California. You can't pay me enough money to live in that state.
Click to expand...
Yep! Spent many years commuting into San Diego from Escondido, then switched it up to commute north to Fallbrook. That wasn't bad, except for the Escondido to Camarillo (north of Los Angeles) once a month. Now THAT drive was worse than a root canal!
 
Brian Austin said:
I'll take just about any big city in the US over Southern California. You can't pay me enough money to live in that state.
Click to expand...
With apologies to the NorEasters here, the summer I spent in Boston a couple of years ago qualifies, in my opinion, as the worst city in the world to drive in. Beats Naples, Italy and Subic Bay, Phillipines hands down.
 
Ah, Greg - it's all in your attitude... :) That and timing your commute right!
 
gkainz said:
Yep! Spent many years commuting into San Diego from Escondido, then switched it up to commute north to Fallbrook. That wasn't bad, except for the Escondido to Camarillo (north of Los Angeles) once a month. Now THAT drive was worse than a root canal!
Click to expand...
We've got an office in Escondido. I dread that drive. If I had a plane, I'd be flying into Carlsbad instead of trucking it over.
 
gkainz said:
With apologies to the NorEasters here, the summer I spent in Boston a couple of years ago qualifies, in my opinion, as the worst city in the world to drive in. Beats Naples, Italy and Subic Bay, Phillipines hands down.
Click to expand...

I wonder if Boston driving has become easier since completion of their version of the "Chunnel". What did they call it? It took way longer than expected and a lot more $$$ to complete, but is it working?
 
Anthony said:
I wonder if Boston driving has become easier since completion of their version of the "Chunnel". What did they call it? It took way longer than expected and a lot more $$$ to complete, but is it working?
Click to expand...

The "Big Dig," which I read is leaking like a sieve and has some folks vociferously questioning it's safety. The city politicians seem to be going to great lengths to reassure everyone that it's perfectly safe though. Personally, I have a sneaking suspicion that we'll be reading a disaster story sooner or later. Good luck, Bostonians!!
 
I'm working a consulting gig right outside the Big Dig right now (at the Federal Reserve Bank). I don't think this thing is every really going to end. It's fixed some traffic issues but has also created some. I don't know if it's a net positive or negative...
 
BillG said:
Ah, Greg - it's all in your attitude... :) That and timing your commute right!
Click to expand...
You mean the Boston commute? I flew in on Sunday night, so the taxi ride to Cambridge was pretty mellow, but trying to get back to Logan on Friday afternoon was something else! The cab driver told me that lane lines and traffic signal lights are just mild suggestions, and everyone just makes up the rules as they go. I believe him! The cabs in Naples were mild in comparison, even when we told them there was an extra 20,000 lira for them if they "really stepped on it!" Even the jeepneys in Olongapo were more sedate than Boston cabs!
 
gkainz said:
Even the jeepneys in Olongapo were more sedate than Boston cabs!
Click to expand...

You didn't do any drinking there did you Greg? :)
 
gkainz said:
With apologies to the NorEasters here, the summer I spent in Boston a couple of years ago qualifies, in my opinion, as the worst city in the world to drive in. Beats Naples, Italy and Subic Bay, Phillipines hands down.
Click to expand...
Yes, and have you noticed that when you're driving on the Cambridge side, if you don't know your bridges you'll keep crossing them by mistake and ending back up on the Boston side? My first time in Cambridge, I went to Boston about six times.
 
LOL - I don't take cabs! Unfortunately around here the big problem is construction - it NEVER ends. They just started ripping up the Mass Pike for re-paving now, too. Just when I bought a new motorcycle. Sigh - I don't want to ride on that cr@p!
 
Re:Olongapo and Subic Bay; was radar

Anthony said:
You didn't do any drinking there did you Greg? :)
Click to expand...
Moi? :rolleyes: :no: "That's my story and I'm sticking to it."

Altho I can tell you that "I've heard" you don't want to drink San Miguel beer from the hand painted bottles and balutes taste worse the next morning and any meat on a stick purchased from a street vendor is best eaten in the dark...
 
Re: Olongapo and Subic Bay; was radar

gkainz said:
Moi? :rolleyes: :no: "That's my story and I'm sticking to it."

Altho I can tell you that "I've heard" you don't want to drink San Miguel beer from the hand painted bottles and balutes taste worse the next morning and any meat on a stick purchased from a street vendor is best eaten in the dark...
Click to expand...

I loved the San Migs. The hand painted bottles just added an element of adventure :) And formaldehyde, if the tales are true.
 
Bill Suffa said:
Could be dust. "ground clutter"
Click to expand...

Eric Davis said:
Dust most likely....I have also heard of this when certain conditions are right(particulate, temp, mositure...) this happens at sunrise and sunset for some reason...at least thats what some radar controllers have told me.
Click to expand...

I didn't see the echo's you posted, but if the returns were of an increasing diameter round shape, it most likely was due to a low tilt angle. On the WSR-57 (pre-NEXRAD) radars, this was often the result of an operator tilting the antenna down to near the horizon. I think the same thing is possible with WSR-88 (NEXRAD).

If you saw an irregular return consisting of a relatively narrow band over 30-90 degrees of azimuth, especially over a coastline, a river, a lake, or an area of wetlands, you are probably looking at "anomalous propagation" or AP. This is where the boundary between two airmasses refracts the outgoing radar signal towards the earth and the return back towards the horizon and antenna. This is similar to the effect that causes the sun to appear to get larger as it gets near the horizon. From what I've heard, there were several severe storm warnings posted as a result of someone misinterpreting AP as the real thing before this was widely understood.

What is commonly called "ground clutter" is the result of side lobe emissions (parts of the transmitted signal that go in unintended directions) reflecting off stuff on the ground.
 
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