Bob's Findings - May 2010 Article - NEXRAD Doppler images of the Wisconsin meteorite fall of 4/14/2010

An Article In Meteorite-Times Magazine
by Robert Verish

What Made the Recovery of Meteorites from the 4/14/2010 Fall in Wisconsin such a Rapid and Timely Success?

The quality of Doppler-radar weather images from NOAA is the main reason.

There has been much written about the April 14th fireball and fall of meteorites in Grant and Iowa County in Wisconsin. [As of the publishing of this article, there still has not been a formally-approved name assigned to this meteorite] And there is little that I can add to this subject, at least, until I pay a visit to this strewn field. But the subject is still very timely, and if a contribution could be made that would assist in the recovery of meteorites from that fall, then "now" would be an appropriate time to publish that kind of information.

So, that is why in lieu of my regular article in this month's edition of Bob's Findings, I've dedicated this space to Rob Matson and his images of doppler-radar from the NOAA National Weather Service (NWS). Rob had posted a message to the Meteorite-List, seeking a photo repository in which his images could be archived and so that his data could be shared. Although Rob received many immediate replies, it was my offer of this month's edition of Bob's Findings (with the portal through Meteorite-Times. Com) that made it a sensible choice .

The data in the images could use a little explanation in order for them to be utilized properly, but let's take a look at them, now:

May 2010 - Here are links to Rob Matson's images of the NOAA-NWS NEXRAD Doppler-radar reflections of the Wisconsin meteorite fall of April 14th, 2010:

Here are some comments from Rob Matson regarding his images:

"These files will require some explanation for people unfamiliar
with Doppler radar to interpret correctly. The fast scan direction
for Doppler is in azimuth (clockwise). The slow scan direction is
in elevation, from lowest elevation angle to highest. So each full
volume scan consists of 5 or more full sweeps in azimuth, with
one (and sometimes two) sweeps at each elevation angle.

"There were three radars that "detected" the Wisconsin fall: La
Crosse, WI; Milwaukee, WI; and Davenport, IA. The Milwaukee and
Davenport radars each detected the dust/smoke trail in two scans.
However, the La Crosse radar was operating in an unusual mode at
the time of the fall, generating a full volume scan in about
4 minutes 15 seconds, consisting of 17 (!) individual elevation
angle slices, one every 15 seconds.  As a result of this fast
scan rate, La Crosse captured 11 separate images of the fall:
completely unprecedented in all of the US and southern Canadian
falls detected by NEXRAD in the last 15 years.

"Listed above are fifteen images in time sequence, where the
filename indicates both the radar that generated the image, and
the time (GMT) of the particular elevation angle scan when it
passed over the bolide cloud location. Note that there is a
time recorded in the third line of the column of data to the
right of the radar image, but that this time corresponds to the
*start* of a full volume scan -- not the time of the particular
elevation angle slice displayed."

And Rob Matson adds, "Enjoy the images! I hope you find them useful."

So, in answer to this article's subject title question, "How were they able to find the meteorites so soon after the fall?"
I feel that it was the high-quality of the NWS Doppler-radar with its very distinctive trace of the fireball (which was readily available to the general public) that was the impetus to getting the meteorite hunters so quickly into the [strewn] field.

References:

Discover Magazine:
Huge fireball over Wisconsin! | Bad Astronomy | - Apr 14, 2010 ... Rob Matson Says: April 16th, 2010 at 12:25 am ... The story doesn't say where the find was made, but my educated guess (based on Doppler radar imagery) is that it was recovered ...

Shawn Alan:
Meteorite Fall Wisconsin - in MeteoritesRock.com -
The interesting facts, video news reports, newspaper etc.

Bob's Findings:
February 2009 Article - in Meteorite-Times.Com -
"What Made the Recovery of Meteorites at West, TX such a Success?" - Comparison of some recent bolide events.

NEXRAD:
Next-Generation Radar - in Wikipedia -
is a network of 159 high-resolution Doppler weather radars operated by the National Weather Service, an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United States Department of Commerce.

FBWG:
Fireball Working Group - The purpose of this group is to exchange data regarding fireball events and to provide a venue for experts and novices to assist field investigators in collecting and analyzing reports from whatever traditional or non-traditional sources there maybe.

My previous articles can be found *HERE*

For for more information, please contact me by email: Bolide*chaser