[meteorite-list] How to compute NEXRAD radar hit times

From: Jim Wooddell <nf114ec_at_meteoritecentral.com>
Date: Mon, 24 Jan 2011 07:51:37 -0700
Message-ID: <117AC002E54A495F99477323959AF673_at_Grande>

Marc, Rob!

I found my error. However, when I originally tried this about a month ago,
I could not duplicate 03:02:31. This was the biggest issue. I did not
capture this so I do not know why. Maybe I was using level III.

In any case, I was not changing the radial properties and I did not catch
that. When I fired it up this morning, I was actually getting a radial
properties pop-up screen, which I did not get before. That brought my
attention to it and the default is very low...in the decimals. So I
selected 15.69 and loaded that and there it was!! It is the only angle that
shows it. I tried the 12 and 19 degree cuts to see. So, that issue is
solved and thanks to you and Rob for your assistance. I was totally
successful this morning with the entire process.
This leaves me to wonder how 15.69 degrees was chosen. Were all the
elevation angles checked or was it because of witness statements???

The Google maps tie in is a good idea. Every in regards to overlays is
pretty much there.
It would be nice to have two features added or changed. Coordinates with
the ability to match the most common standards, selectable. DD.dddd,
DD_MM.mmm, DD_MM_SS ( datum selectable too) and then the ability to move
the map by inputting coordinates. Also, the program appears to default to
the +Zoom value, I would suggest it be defaulted to just the movement of the
map.

Kind Regards,

Jim Wooddell

----- Original Message -----
From: "Marc Fries" <fries at psi.edu>
To: "Jim Wooddell" <nf114ec at npgcable.com>
Cc: "Meteorite-list List" <meteorite-list at meteoritecentral.com>;
<Steve.Ansari at noaa.gov>
Sent: Monday, January 24, 2011 1:03 AM
Subject: Re: [meteorite-list] How to compute NEXRAD radar hit times


That data file is telling you a few things, namely the data type (Level II
as opposed to Level III), the station name (KARX, La Crosse, WI), the date
and time of the data set that this data comes from, and a few other things.
The important other things are the VCP code (Volume Coverage Pattern, or the
pre-set combination of radar cuts and rotation speeds used) and the
elevation angle (15.69 degrees - very high!). To replicate this data, go to
the NOAA radar download page:

http://www.ncdc.noaa.gov/nexradinv/

...and request the 03:02 UTC data set from 04/15/2010 from the KARX radar.
You'll have to request all the data between 0300 and 0400 to do so. Then
once you have the data file in hand, you open the 0302 UTC file and select
the 15.69 degree cut for viewing in the NOAA software, then find the
location shown in the image. (For a good time, check out the velocity on
that particular object - it reads zero even though the location and timing
indicate that you're looking at the fireball while it is still optically
bright!)

That's what should work, anyways; I'm not actually trying this as I type.
There have been some errors in the NOAA software recently where data simply
won't read. I don't know what's up with that, but using an older version of
the software may help.

Cheers,
Marc Fries
Received on Mon 24 Jan 2011 09:51:37 AM PST