[meteorite-list] 2nd Report from Strewnfield in Edgewood Texas

From: Marc Fries <mfries8_at_meteoritecentral.com>
Date: Tue, 7 Feb 2012 20:48:36 -0800
Message-ID: <BLU0-SMTP1386C4C66EE5FB205046702F17A0_at_phx.gbl>

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" <mfries8 at hotmail.com>
> To: <meteorite-list at meteoritecentral.com>
> 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<nf114ec at npgcable.com> wrote:
>>>
>>>> From: Jim Wooddell<nf114ec at npgcable.com>
>>>> Subject: Re: [meteorite-list] 2nd Report from Strewnfield in
>>>> Edgewood Texas
>>>> To: "Dennis Miller"<astroroks at hotmail.com>,
>>>> mccartney at blackbearddata.com, meteorite-list at meteoritecentral.com
>>>> 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"<astroroks at hotmail.com>
>>>> To:<mccartney at blackbearddata.com>;
>>>> <meteorite-list at meteoritecentral.com>
>>>> 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: mccartney at blackbearddata.com
>>>>>> To: meteorite-list at meteoritecentral.com
>>>>>> 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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>>>>>>
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Received on Tue 07 Feb 2012 11:48:36 PM PST