Question about Radar

[Kyle Masters]

With the standard NWS radars, 0.5, 1.5, 2.4, and 3.4* tilts, what is the standard height increase per mile for those?

Say I was 60 mi away from the radar at a 1.5* tilt, how high is radar looking?

 

[Kevin Scharfenberg]

The roughly-correct equation is

H = R(tan L) + (R*R)/17000

where
H = height above radar level in km
R = range from radar in km
L = Elevation angle

60 miles = 96.56 km so at 1.5 degrees the altitude is (96.56 * tan 1.5) + (96.56*96.56)/17000 = 3.08 km above radar level, or about 10,100 feet.

Hope that helps.

 

[Aaron Kennedy]

Kevin means it is the "good enough for government work" equation

Aaron

 

[Jeff Snyder]

With the standard NWS radars, 0.5, 1.5, 2.4, and 3.4* tilts, what is the standard height increase per mile for those?

Just to point out, those tilts are the the tilts available on the NIDS feed. The NWS offices have many many more levels at their disposal, and Level II data provides many more, different levels... E.g. a quick look at my level II data shows 0.5, 0.8, 1.2, 1.7, 2.2, 3.0, 3.9, 5.1, 6.2, 7.8, 9.8, 12.3, 15.5, 19.3 degree tilts available (as viewed on "GRW88Level2" while the radar is operating in VCP12)... Of course this depends on the VCP that the radar is operating in.

 

[Aaron Kennedy]

You checked out GRWW88D level 3 Jeff? I see no reason to use any other radar service after using that. Live radar within several minutes, auto update, GIS support. yum!

Aaron

 

[Kyle Masters]

where do you guys get all that stuff?

 

[mikegeukes]

Here are the different tilt angles for the different VCP's, somebody correct me if this has change. I have notice small variations in terms of degrees in some of the tilt angles, that are listed in different literature.

I have notice when using Level 3 data, you will see a differece of 0.1 degree in the tilt angle, depending on source of your radar data, you are getting over the internet. Example of different tilt angles: 2.4 degrees for Weather Tap, 2.5 degrees for College of Du Page for base reflectivity, or storm relative velocity images.

Precipitation Mode Strategy:
Volume Coverage Pattern 11 (VCP 11) scans 14 elevation (tilt) angles in 5 minutes
Elevation (tilt) angles: 0.5, 1.45, 2.4, 3.35, 4.3, 5.25, 6.2, 7.5, 8.7, 10.0, 12.0, 14.0, 16.7, 19.5 degrees
Elevation (tilt) angles: 0.5, 1.50, 2.4, 3.40, 4.3, 5.30, 6.2, 7.5, 8.7, 10.0, 12.0, 14.0, 16.7, 19.5 degrees (from other sources)
Volume Coverage Pattern 12 (VCP 12) scans 14 elevation (tilt) angles in 4.1 minutes
Elevation (tilt) angles: 0.5, 0.8, 1.2, 1.7, 2.2, 3.0, 3.9, 5.1, 6.2, 7.8, 9.8, 12.3, 15.5, 19.3
Elevation (tilt) angles: 0.5, 0.9. 1.3, 1.8, 2.4. 3.2, oops lost my notes on the rest of the elevations, lol

Volume Coverage Pattern 21 (VCP 21) scans 9 elevation (tilt) angles in 6 minutes
Elevation (tilt) angles: 0.5, 1.45, 2.4, 3.35, 4.3, 6.0, 9.9, 14.6, 19.5 degrees
Elevation (tilt) angles: 0.5. 1.40, 2.4, 3.40, 4.3, 6.0, 9.9, 14.6, 19.5 degrees (from other sources)
Elevation (tilt) angles: 0.5, 1.50, 2.4, 3.50, 4.4, 6.0, 9.9, 14.6, 19.5 degrees (from other sources)

Clear Air Mode Strategy:
Volume Coverage Pattern 31 (VCP 31) scans 5 elevation (tilt) angles in 10 minutes
Elevation (tilt) angles: 0.5, 1.50, 2.5, 3.50, 4.5 degrees
Elevation (tilt) angles: 0.5, 1.45, 2.4, 3.35, 4.3 degrees (from other sources)

Volume Coverage Pattern 32 (VCP 32) scans 5 elevation (tilt) angles in 10 minutes
Elevation (tilt) angles: 0.50, 1.50, 2.50, 3.50, 4.50 degrees
Elevation (tilt) angles: 0.50, 1.45, 2.40, 3.35, 4.30 degrees (from other sources)

Mike

 

[Bob Hartig]

Aaron, how can I access GRWW88D?

 

[Aaron Kennedy]

Try: http://www.gibsonridgesoftware.com/forums/

Aaron

 

[Kyle Masters]

how do you get that program to show different radars?

 

[James McCormick]

Paul Sirvatka and the College of DuPage have a great little tutorial on doppler radar and applications:
http://weather.cod.edu/sirvatka/es115/unit.../radarnotes.pdf

At the bottom of the page, there is a figure showing the elevation of a radar beam given an initial angle and distance from the radar.

Hope that helps. Remember to keep in mind any elevation difference between the radar location and the point at which you want to look.

 

[Bob Hartig]

Thanks, Aaron. That website seems to be just a users' forum to the radar itself, but I can probably find out from it how to access the actual radar.

 

[Kyle Masters]

go to www.gibsonridgesoftware.com/grw88level2
or www.gibsonridgesoftware.com/grw88level3

 

[Bob Hartig]

Perfect! Thank you, Kyle.

 

[Jeff Snyder]

You checked out GRWW88D level 3 Jeff? I see no reason to use any other radar service after using that. Live radar within several minutes, auto update, GIS support. yum!

Aaron

:shock: No, I hadn't seen the Level III program before now. I've used the LII program for the past couple of months ... But this LIII program -- WOW! Who needs Storm Lab, Weathertap, etc etc etc?! This program does it all, pretty much... All 4 NIDS tilts -- on bref, radial, SRM, VIL, echo tops, storm attributes table, county warnings, etc etc etc... and it's free!