Author Topic: "T" radar, dont like em.  (Read 3154 times)

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Offline mackbig

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"T" radar, dont like em.
« on: May 26, 2011, 05:10:29 PM »
EDIT:changed subject line from "HD radar" to "T radar" based on feedback.

I know its not GRlevelx's fault.  But cant think of anywhere else to post this.

HD radar sucks in my opinion.  I much prefer the K radars, to the T radars.
Here's an extreme example. Tor warning in Allegany MD.  Click on the link within the warning window. It takes you to TIAD.  It shows absolutely no rain, all the watch/warning boxes are there.  Click on nearby KLWX, and all the storms show up, including the MESO symbol of the severe tstorm.

In general the images dont look as good, and that is not HD to me.  Whenever I end up on a T radar, I immediately click on the nearest K radar.  Hope buffalo K stays up for a while, they dont have a T yet.

I will post some images once I shrink them.

Andrew
« Last Edit: May 26, 2011, 05:40:16 PM by mackbig »

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Offline WeatherHost

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Re: "hd" radar, dont like em.
« Reply #1 on: May 26, 2011, 05:23:21 PM »
I don't think "T" equals HD.  TDWR is Terminal Doppler Weather Radar and these are the systems installed at airports (terminals).  They are shorter range since they're only intended for control tower usage.  K sites will not be replaced by T sites.

You may be thinking of the Dual-Pol sites which as far as I know aren't on-line yet.




Offline mackbig

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Re: "hd" radar, dont like em.
« Reply #2 on: May 26, 2011, 05:23:50 PM »
Here is the current image from both

HD

Old school


I thought at first this t radar was totally down, but there are a few storm tracks visible, and if you squint you can see some colour.  Usually the images are smaller, and dont show the true size of the storm.  Just seems counter to the concept of high def.

Andrew

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Offline Downlinerz2

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Re: "hd" radar, dont like em.
« Reply #3 on: May 26, 2011, 05:34:50 PM »
    The Terminal Dopplers are good at short range but that is all.  I don't think that is where the HD or Super Res radars come from.  One TV station here has a radar on it's website that has the regular type radar with the smoothed red blobs moving.  Then you can set it to Local Super resolution.  I thought it was Terminal Doppler for a long time.  But then I noticed you can change it to sites that don't have the Terminal Dop radars. The local Super Resolution has pixels that are very thin but the radials are wider.  So you get a clearer picture like a CAT scan set to thinner slices.  Unfortunately it cannot be smoothed which isn't bad really but there is nothing else on it but lightning.
    Mark

Offline neondesert

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Re: "T" radar, dont like em.
« Reply #4 on: May 27, 2011, 12:22:59 AM »
Hi Andrew,

The Terminal Doppler Weather Radar's or TDWR are, as WeatherHost states, intended for the use of of major airports.
Here is a short WIKI article about how they work: http://en.wikipedia.org/wiki/Terminal_Doppler_Weather_Radar
 
As a side note, my first view of the McCarran TDWR was while visiting the local NWS office.  The Met that I spoke to stated
that they use it in conjunction with the regular Doppler radar KESX.  One thing that really stood out at the time
was that the TDWR was "blind" in the East and Northeast directions because it is located at the base of Frenchman's mountain.  This allows
it to have a great view of the airport which of course is its primary purpose.

I did notice that the WeatherUnderground labels the TDWR's as High Def.  While this may be technically correct it's a bit misleading
as they are setup for airport use and will not see all the precip that may be falling over an area.
Larry
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Offline IMADreamer

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Re: "T" radar, dont like em.
« Reply #5 on: May 27, 2011, 10:18:21 AM »
I never use the T radars, I always stick with the K NWS radars. 
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Offline W Thomas

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Re: "T" radar, dont like em.
« Reply #6 on: May 28, 2011, 12:12:11 AM »
EDIT:changed subject line from "HD radar" to "T radar" based on feedback.

I know its not GRlevelx's fault.  But cant think of anywhere else to post this.

HD radar sucks in my opinion.  I much prefer the K radars, to the T radars.
Here's an extreme example. Tor warning in Allegany MD.  Click on the link within the warning window. It takes you to TIAD.  It shows absolutely no rain, all the watch/warning boxes are there.  Click on nearby KLWX, and all the storms show up, including the MESO symbol of the severe tstorm.

In general the images don't look as good, and that is not HD to me.  Whenever I end up on a T radar, I immediately click on the nearest K radar.  Hope buffalo K stays up for a while, they don't have a T yet.



I will post some images once I shrink them.

Andrew


I think I may have noticed the same thing with the same storm while messing around with Gr2AE and clicking on the storms from the warnings window and it ended on a Terminal Doppler site and it was showing absolutely nothing!  I first thought that the WFO had lost their mind but like you said move to an adjacent site and it shows it all !  I have noticed a lot of vendors referring to their radar as HD lately and as far as I knew there actually is no such beast only Super Res.  Some of have different color curves and that's what they consider HD I think :)

I'm with you the T Doppler sites don't seem to excite me much :)


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Offline neondesert

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Re: "T" radar, dont like em.
« Reply #7 on: May 28, 2011, 12:33:10 AM »
From the Wiki article (in case nobody took the time to read it...it's really short.)  ;)

Quote
Shortcomings

The shorter 5 cm wavelength, which is closer to the size of a raindrop than the 10 cm wavelength, is partially absorbed by precipitation. This is a serious drawback to using TDWR, as the signal can be strongly attenuated in heavy precipitation. This attenuation means that the radar cannot "see" very far through heavy rain and could miss severe weather such as strong thunderstorms which may contain the signature of a tornado, when there is heavy rain falling between the radar and that storm. When heavy rain is falling on the radome, the range of the TDWR is further limited.[1][2] Finally, hail in a thunderstorm scanned by a TDWR can entirely block the signal as its size is larger than the wavelength.[1][2] So a total attenuation behind a storm should raise the possibility of hail in the observer's mind.

A second problem is the smaller non-ambiguous radial velocity or Nyquist velocity. In the case of the TDWR, this means the velocity of precipitations moving at a speed beyond 30 knots away or toward the radar will be analyzed incorrectly because of aliasing. Algorithms to correct for this do not always yield the proper results. NEXRAD has a threshold that is twice as high (62 knots) and thus less processing and interpretation are needed. Because of this, the resolution of radar reflectivity for small scale features such as mesocyclones might be better in TDWR, but the velocity resolution may be worse.

Thus, it is best to use the TDWR in conjunction with a traditional NEXRAD nearby to ensure that nothing is missed.

The last sentence sums it up and is exactly how the meteorologist at the Vegas WFO explained it to me.

Again, this is a tool designed primarily for detection of wind shear at major airports.  The fact that we or the media outlets have access to it is just a bonus.

Here is another article on them from the WeatherUnderground

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1168

I think their decision to call the product High Def. just confuses the issue.  :roll:  #-o
Larry
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Offline LFWX

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Re: "T" radar, dont like em.
« Reply #8 on: May 28, 2011, 12:41:46 AM »
I am fortunate enough to have TDWRs north and south of me (TCVG & TDAY), while also having the normal doppler radars east and west of me (KILN & KIND).

4 views of the same storm! 4 locations for collecting velocity data!

So, I love them.
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