High-Definition Radar on Web Sites

[czenzel]

Hi everyone,

I am seeing that a High-Definition Radar format is being used on sites such as AccuWeather or Weather Underground. I also noticed that only a select number of stations are offering this technology.

Has anybody heard about this technology that web sites are using?

How can this improve weather forecasting with a high-def radar with .20 resolution at 48nm?

Also, can anybody tell me what NEXRAD product they are using to develop these maps (Level III, Level II)?

Here is a sample link that shows the HD radar on Weather Underground: http://www.wunderground.com/radar/radblast.asp?ID=EWR.

Thanks,
Christopher Zenzel

 

[L.B. LaForce]

Ahh yes, its the new TDWR (Terminal Doppler Weather Radar) radars. They are used by airports, for safer air travel, to detect things like microbursts, windshear, etc.

Here is a couple good articles on them: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1168

http://www.docstoc.com/docs/879403/...-Radar-for-NWS-Operations-Phase-Update---TDWR

 

[rdale]

It's only in Level III format for now... GRLevel3 reads the data in - more sites will be added next year as this beta software becomes official.

 

[Chris Nuttall]

TDWRs have actually been around since the mid 1990s. Until now, NWS did have enough bandwidth to make TDWR data available to the public.

 

[czenzel]

Thanks for the great input everyone!

Does anybody know if Digital Atmosphere supports this format?

 

[Mike Smith]

Hello everyone,

Glad you are noticing and liking the super-resolution radar that is displayed at www.accuweather.com (our parent company).

Actually, the super-resolution comes from all of the NWS WSR-88D's (as well as the TDWR's). It has eight times the resolution of the original Level II data. Our system, still officially in beta, mosaics the data every five minutes and declutters it very quickly, just a matter of seconds.

As always, we welcome any comments or suggestions. You can private message me, email me at msmith AT weatherdata.com or use the comment feature at accuweather.com .

Note: For the forseeable future, the military and F.A.A. -88D's will remain at conventional Level II resolution. We do include those in the mosaic but the pixels are, of course, larger.

Mike

 

[rdale]

Mike - your reply is incorrect, I think you may have passed over his link and his radius of radar coverage too quickly

He was asking about EWR and the like, which are NOT in Level II format and do NOT come from 88D's. Those are TDWR units, which are not operated by the NWS and are not distributing data in Level II (neither high nor low-res.)

 

[Mike Smith]

Rob,

I am very familiar with how accuweather.com gets its data because it is created here at WeatherData Services, Inc. (owned by Accuweather) and it was part of the original post.

That said, yes, the Terminal Doppler Weather Radars are operated by the Federal Aviation Administration and have native resolution that is higher than the WSR-88D's. The super-resolution of the -88D's is created by oversampling the azimuth and displaying each range bin individually rather than averaging which was the case with the original Level III data.

Each radar type has its strengths and weaknesses. For example, the -88D's are 10cm (S band) radars (less attenuation) while the TDWR's are 5cm (C band) radars (more attenuation, especially when over or close to the radar). If anyone is interested, I'd be happy to provide more information.

And, it is correct that more TDWR's will be coming on-line in 2009.

Best wishes and Happy New Year everyone.

Mike

 

[Bob Hartig]

What I'd really like is a means of comparing similar radar images so I can see how regular L3 (and, for that matter, L2 hi-res) compares with TDWR L3. I've been to the six different TDWR sites, but so far, between last night and tonight, there just hasn't beent any decent convection occurring that would let at least one of those sites show its stuff.

Rob, Mike, or anyone in a position to do so, is it possible, without undue hassle, for you to provide some side-to-side samples so that folks like me who are clueless can get a good visual grasp of how much better the resolution is of TDWR over WSR-88D?

 

[Mike Smith]

Bob,

The super-resolution WSR-88D data and the TDWR are approximately the same resolution. The larger difference is due to attenuation assuming a symmetric echo equidistant from each type of radar.

The TDWR is much higher resolution than Level III or standard Level II WSR-88D which is what most web sites use.

Until we get some convection around one of the TDWR sites for which the NWS is now relaying data, it is hard to do a meaningful comparison.

That said, there are metro areas (PHL, CLT, SLC, PHX, LAS) that will have significantly improved coverage with the addition of the TDWR network.

Mike

 

[Bob Hartig]

Thanks, Mike. I thought maybe someone might have some archived images of a single event in the different data formats. But if L2 hi-def and TDWR are of a comparable resolution, then you've just told me what need to know in order to start feeling excited. From the sound of it, my trusty GR3 is going to start rendering much more precise detail from a growing number of locations.

 

[rdale]

Make sure you've updated your GR3 - as TDWR's have been available.

 

[Greg Stumpf]

In addition, the TDWRs include a volume coverage pattern (VCP80) that uses an "interlaced" selection of elevation angle. The advantage is 0.5 degree tilts every 60 seconds. Note that the TDWR VCP90 does not use interlaced elevation angles.

I've also noticed that the TDWRs appear to have better sensitivity in the clear air returns. Boundaries, horizontal rolls, smoke plumes, etc., appear to be easier seen on the TDWRs.

 

[Jim Zandonai]

Here is a couple links that show some TDWR images...

The first link works but where images are suppose to appear they do not materialize..but you can make them appear. Right click in between the text where the image is click on properties. Copy and paste the image url into the address bar and change 'intra' to "www" hit enter and the image will appear. Kind of a pain but it works.


http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=lot&storyid=13680&source=2


http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=lot&storyid=13685&source=2

 

[rdale]

The advantage is 0.5 degree tilts every 60 seconds.

Due to bandwidth issues, that's also another advantage that doesn't make it to anyone... Only every 5 minutes regardless of how often that sweep occurs.