Sorry - I'm sure I do have the HAS numbers, but my inbox is full of HAS
emails and I don't know which is which! Lotta fireballs lately.
And I'm frustrated that we don't have an easy answer to this one on
radar, but not upset. We've made a lot of progress and I'm pleased with
that, and pleased with how useful it is.
As for not ID'ing the meteor, most of the time the radars aren't going
to see a fireball directly. Weather radars look for weather (go figure!
heh) and so they are trained at elevations close to the horizon. The
only time we've ever captured a bright meteor on radar was the Mifflin
fall, and only because it passed at just the right distance from a radar
in high-res mode that included a sweep 19.5 degrees above the horizon.
That was beautiful - the Mifflin fireball shows up at over 28 km
altitude! The radar recorded a velocity of zero for the reflection; I
suspect that the actual speed was far in excess of the measurement
limits of the radar. Getting back to your question... The only radar in
high-res mode was the Shreveport radar, and it was too far away (and
apparently facing the wrong direction at the time) to catch the fireball
directly. The Fort Worth radar only elevated to 4.5 degrees, and the
TDWR airport radars don't elevate very high either.
Cheers,
Marc Fries
On 2/7/12 10:50 AM, Jim Wooddell wrote:
Hi Marc and Steve and all,
My comment that the radar information was off was because of an error
in the camera location to begin searching the radar data?
Garbage in = Garbage out.
Rob figured that out and Jim Gamble confirmed Rob's findings.
So, my statement seems to be true in at least one instance. Not the
fault of the radar and I felt the frustration!
I think fine tuning on where the information to research comes from is
key and it's improving all the time.
Marc, do you have HAS numbers I could bum? I am not actively
searching this one, just want to see what you are seeing.
It's a little surprising that this fireball was not clearly
distinguished and Id'ed on radar in my mind. Why do you think that is???
As a point of information, at least on the Sky Sentinel network, the
node operator can create a movie, regardless of the "event" capture
timing.
I can set the event capture to a very low time. Because it is there
to capture an event, all I need is the beginning time to then go back
and make a movie that will "see" the entire event plus added time
prior and after to determine any kind of flash, etc., many seconds
after the event leaves my horizon. It's easy and only takes a few
minutes to do. IOW's, the movie, is only dependent on the event
capture to get a relative time to begin...and that's it.
Knowing this, the radar guys (me included) can then call or email the
node operator directly and get the correct information and data....the
keyword being "directly".
Some operators, like me, may even order up the HAS data and have that
being processed, so that order number can be shared as well, which can
save some time as well when contacted!
In regards to the sonic booms, that's great to hear all the witnesses
heard it. However, have there been any time delays recorded? I have
not seen any posted.
Kind regards,
Jim
Jim Wooddell
https://k7wfr.us
Parker Sentinel SkyCam
----- Original Message ----- From: "Marc Fries" <[email protected]>
To: <[email protected]>
Sent: Tuesday, February 07, 2012 10:16 AM
Subject: Re: [meteorite-list] 2nd Report from Strewnfield in Edgewood
Texas
Rather quietly and "behind the scenes", there has been a lot of work
developing the use of weather radar to detect meteorites, by Rob
Matson, Jake Schaefer, myself, my brother, and others. It's been a
tall learning curve but I think we've made a lot of progress. In my
opinion, the biggest "unknown" left at this point is to figure out
what size of meteorites and/or other debris actually show up best in
radar data. The radar reflections we see are not only reflections off
of solid objects but also from atmospheric turbulence. And we also
have to unravel the knot of reflections in the Mie scattering regime,
where the reflected signal strength varies widely - and nonlinearly -
with the size of the reflector. The upshot is that we are still
working on sorting out what radar reflection equates to what size of
meteorite. If we see a radar reflection, is it from search-worthy
stones or just a cloud of ~1g rocks, or even ablation spherules? A
good part of that is just a matter of timing, but not all of it.
Lorton, for example, produced a strong radar signature in TDWR radar
data but nothing was found beyond the original
doctors'-office-smasher, suggesting that we were looking at a swarm
of tiny rocks....? The same is true for the Jacksonville, IL event.
This DFW fireball appears to come from a well-consolidated object
that survived a long "burn" time with little in the way of
fragmentation. West, TX, by comparison, fragmented extensively and
produced a beautiful, easy to follow set of radar signatures. My take
on the DFW fireball is that we're looking for a small number of large
rocks that reached the ground quickly, producing a short-lived radar
signature that requires some degree of luck to figure out. ...or are
we looking at 1g stones that no one is going to find? Just having
that answer in hand will tell us a lot about where to look.
Still working on it...
Cheers,
Marc Fries
On 2/7/12 8:46 AM, Steve Dunklee wrote:
The radar data is not off. It is just not understood by most people
how the parabola of a fall can cause the actual landing area to be
up to 12 miles away from the radar data. If you stick a french curve
in an apple to represent the west to east fall. the termination
point is north to northwest of the radar data.
Cheers
Steve Dunklee
--- On Tue, 2/7/12, Jim Wooddell<[email protected]> wrote:
From: Jim Wooddell<[email protected]>
Subject: Re: [meteorite-list] 2nd Report from Strewnfield in
Edgewood Texas
To: "Dennis Miller"<[email protected]>,
[email protected], [email protected]
Date: Tuesday, February 7, 2012, 4:29 PM
Hi All!
I thought it was determined the Radar data was off???
And, it really is not a strewn filed until one is actually
found!
Cheers!
Jim
Jim Wooddell
http://k7wfr.us
----- Original Message -----
From: "Dennis Miller"<[email protected]>
To:<[email protected]>;
<[email protected]>
Sent: Tuesday, February 07, 2012 8:55 AM
Subject: Re: [meteorite-list] 2nd Report from Strewnfield in
Edgewood Texas
Nice! I am so glad you didn't set the public price too
high, like
Thousands
for Ash Creek. :-) I do hope you are successful in your
hunt. Keep us
posted.
Missed you in Tucson! Again, Good Luck!
Dennis Miller
From: [email protected]
To: [email protected]
Date: Mon, 6 Feb 2012 22:17:55 -0700
Subject: [meteorite-list] 2nd Report from
Strewnfield in Edgewood Texas
Nothing has been found where the radar data said it
might be. Torvald
and Donavan have left the zone replaced by Stephen
Thompson out of
Fredricksburg TX who is an expert on Sonic Boom
characteristics.
I've been lucky enough to get some media attention
to try to motivate
the public to assist here is today's interview on
TV. This is the 5 TV
interview I've given since arriving.
http://dfw.cbslocal.com/video/6713580-meteor-hunters-scouring-north-texas/
We spent the day interviewing more witnesses&
compiling and extending
the range of sonic boom farther to the east to
include Wills Point, and
southern Lake Tawakanii.
We'll do some field samplings tomorrow east of 19.
Also as a warning. I've heard from a local that the
landowner who owns
the land in the north where the upper radar blip
is, has gotten very
hostile to all outsiders. The local warned me to
tell everyone to stay
off that property. He thinks the landowner may
shoot to wound or maim.
So I'd like everyone to take that threat to heart.
At this point, we have two new important
observations and think the
strewnfield to be east of 19 now.
At this point, there have been no Z sightings, but
the Black Panther
remains a constant threat. 5 dogs were killed.
Also, the park rangers
at the state park warned us that a mountain lion
has been spotted in the
area.
Some sonic boom activity has been traced back to
some individual using
some kind of reactive explosive that detonates when
shot by a bullet.
The local police has informed us this has been a
bit of a problem for
weeks. Consequently, it really screws up our
acoustical survey.
and a mention and big hand to Dirk Ross, David
Gonzales, and Marc Fries
for giving us back support.
-mccartney taylor& stephen thompson
(meteorite hunter) (offical panther bait)
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