Replacement For Aging Doppler Radar Being Tested

longacre writes "Due to its limited range and slow scan times, the backbone of weather prediction in the US since the early 1990s, the NEXRAD radar system, is deeply flawed in the eyes of meteorologists. A new system being tested by researchers at the NOAA and four universities called the Collaborative Adaptive Sensing of the Atmosphere (CASA) network aims to fill the holes left by NEXRAD, using radar nodes piggybacked onto existing infrastructure, such as rooftops and cell towers. From the article: 'Based on faster and more comprehensive data collection, [Distributed Collaborative Adaptive Sensing] processing can refocus the CASA radars on a particularly interesting part of a storm (like an area that looks like it might develop a tornado) without losing track of an entire storm cell. "The system is continuously diagnosing the atmosphere and reallocating resources using wireless Internet as a backbone," says [the CASA team director].' Testing has begun in Oklahoma, Houston, and Puerto Rico, and initial installations could begin in 5 years."

Comments

First ping

[Anonymous Coward]

10.75 us before anyone else

sounds-like-a-freight-train dept

[Anonymous Coward]

>>sounds-like-a-freight-train dept

Naw, sounds like a friggin shark...

Stealth hunter?

[AHuxley]

In many parts of the world this would be cover for a new passive radar system :-)
http://www.globalsecurity.org/org/news/2001/e20010619stealths.htm

Re:Stealth hunter?

[Rich0]

Such a system may not have much utility in a serious war. There are a few good reasons:

1. At best they give you an idea of where a target is - they're not suitable for guiding missles towards a target and shotting it down. That requires continuous illumination, which is hard when the illuminator doesn't easily get any feedback as to whether it is on target or not, and a missile can't see the reflections reliably.

2. It still depends on RF transmission to illuminate a target, but instead it uses "civilian" transmitters instead of military ones. I use the term civilian very loosly since if your cell phone network is used to illuminate military aircraft it is no longer a civilian technology. In a war with serious stakes an enemy would just fire anti-radiation missiles or artillery at anything that emits RF.

3. Civilian transmitters don't tend to have much in the way of infrastructure redundancy like military ones do. Blow up all the local power stations and batteries should be dead within a day or two, and blow up the fuel depots and even diesel generators aren't going to be much help - cell towers don't typically have huge fuel reserves like a military base would.

The main advantage of this sort of technology would be the ability to use super-cheap transmitters in combination with super-expensive receivers. Since the two are not in proximity it would be much easier to conceal the expensive detection equipment, and transmitters could be made more disposable.

In a less serious war you could rely on the reluctance of an enemy to destroy infrastructure that is primarily civilian in nature. However, in a less-serious war the enemy will probably not be so dependant on defeating your radar system - the only reason wars aren't fought seriously is because the conclusion is evident from the start.

Outdated information

[lpangelrob]

From the article...

Under the current NEXRAD Doppler system, a warning could be statewide, leading to false alarms for most of its residents.

No, not so much. The National Weather Service has started issuing storm-based (polygon-area based) warnings since August 2007. Prior to that, they were county-based warnings, which were a problem (Cook County, IL being about 50 miles tall by 40 miles wide, while average tornado widths are about 100 yards) but nowhere near the "statewide warning" the article claims.

Awful FAQ here: http://www.nws.noaa.gov/sbwarnings/FAQ/engage.html

Re:Outdated information

[Anonymous Coward]

Surprise, surprise.

I had some marginal involvment in a Met Radar tender in a country I used to live in (outside USA). The particular application was Met support for air traffic control. The same system as used in the USA was tendered there. We laughed and threw it out. We stopped laughing next day when they started bribing directly and indirectly (through perks and junkets) every single person in the decision process ladder top to bottom.

At the end they lost the tender to a German company which has supplied Radars in nearly all EU countries that do not have their native production. This was all despite wasting a fair amount of money on bribes. They were so technically inferior that it was not even funny. Their only advantage was that even a civil defence force/national guard idiot could operate the kit (it was userfriendly for a radar, that is something which they should get credit for).

All I can say is good bye and good riddance. About bloody time. At present USA is the only country in the world where planes have better Met radar capability and a better idea of what goes on in the atmosphere than ground staff even at some of the major airports.

Re:Outdated information

[morgan_greywolf]

At present USA is the only country in the world where planes have better Met radar capability and a better idea of what goes on in the atmosphere than ground staff even at some of the major airports.

In many areas of the USA, radar is currently being updated and upgraded. One of the most crucial technologies they are adding is

http://www.nssl.noaa.gov/research/radar/dualpol.php

, which bounces both horizontal and vertical waves simultaneously. Such radars can distinguish between a plane, a flock of birds and rain. Some say they are so accurate, they can actually measure a single drop of rain.

One TV news organization in our area already has one, and all of the NEXRADs that NWS uses are supposed to be replaced by like 2010.

Re:Outdated information

[RiotingPacifist]

which bounces both horizontal and vertical waves simultaneously. Such radars can distinguish between a plane, a flock of birds and rain. Some say they are so accurate, they can actually measure a single drop of rain. Some people are also trying to sell you that crap

Re:Outdated information

[andy753421]

Some say they are so accurate, they can actually measure a single drop of rain.

Dual pol doesn't actually provide any higher resolution compared to the existing radar. The standard resolution for a NEXRAD scan is a 1 degree by 1 km area which is nowhere near the size of a single drop of rain. The way the dual pol radars work is based on the size and shape of the individual drops but it's just the average of all the drops in the sample area.

Another new thing that is becoming available is Super-Res data which is simply a decrees in the sample size to 0.5 degrees by 0.25 km. See here for a comparison. This doesn't change the lowest elevation scans however so that problem still remains.

Better prediction means...

[TapeCutter]

...lives will be saved, OTOH it also increases the likelyhood of a traffic jam of storm chasers in the the exact spot "the finger of God" lands.

Re:Better prediction means...

[Anonymous Coward]

luckily, the jam will resolve itself quickly through natural means

Re:Better prediction means...

[Gilmoure]

That would be soooo coooool! If there was an ice storm on the ground, would be even better. All these SUV's all screeching towards each other and then sliding around trying to avoid crashes and cows why some are being picked up and slammed around!

My God, it will be beautiful!

Re:Better prediction means...

[catmistake]

Right now, NEXRAD affords a 15-20 minute heads up on tornados, and its not clear if that can be increased. Chaos Theory tells us that if we had a grid of sensors in the atmosphere 1 foot apart all around the globe and took a reading, the accuracy of predictions based on that reading would break down in about an hour. Certainly, tornado watches could be issued earlier, but tornado formation happens so quickly there is a limit to how early they could be predicted with any certainty, regardless of how accurate a radar reading.

Offtopic, huh

[Anonymous Coward]

Somebody doesn't know their radar theory. Parent was literally a mile ahead of the game.

Re:Offtopic, huh

[RiotingPacifist]

This is slashdot, only the ACs know what their talking about, being to smart with your first post makes heads asplode.

Rednecks.

[retech]

I use a very tried and true method of weather prediction - Rednecks. If they are by water, there will be a flood. If they are in a trailer park, there will be a tornado. If they are on a hill - a mudslide. In the woods - forest fires.

We could save millions just watching the rednecks and avoiding those areas.

As a side note, I do enjoy the "seed-neck" on the news. You know the one, holding a beer with a stained tank top and in their boxers they always say stuff like: "We lost everythin' but we's gonna rebuild cuz this is our home." It's an aluminum can, how much needs to rebuilt?

Re:Rednecks.

[Anpheus]

It's still property, it's still their home.

And they still lost it.

Re:Rednecks.

[whereareweheadedto]

Very true. It's funny to make fun of rednecks, but when it comes to tragedy, they are still people. Unless they really make the disaster bigger, than it should be, due to their actions.

Re:Rednecks.

[oodaloop]

Well, when you're poor there aren't many great options of where to live. I'm sure if they could afford better real estate, they would move. When I was poor I lived in an apt near an airport because it was all I could afford. If all I could afford in my area was a trailer in a tornado zone, well then I guess that's where I'd live.

Re:Rednecks.

[oodaloop]

I'M on a high horse? For what, pointing out how poor I've been? You're blaming the victim, calling them stupid for living where they do, making fun of the way they talk, discounting all the hardship and turmoil theses people go through, and I'M on a high horse?

Re:Rednecks.

[baldass_newbie]

Why don't you pay for the general lack of intelligence and house these people?

I do. I'm a taxpayer. I also pay for their insurance claims since I live in a low-risk area. Plus I give to charity.
So what's your point, other than you like to ridicule rednecks who have suffered in a disaster?

Re:Rednecks.

[Anonymous Coward]

Yup. The rich rednecks own double-wides.

Re:Rednecks.

[hyades1]

Your term "Seed-neck" threw me a curve. I thought you were going to say that when these folks were interviewed, they'd generally say, "When I seed the twister comin' across the field near to where Bart's trailer was set, I figured I could get on America's Funniest Home Videos if I showed how it made my can of beer pour sideways."

Re:Rednecks.

[Anonymous Coward]

It's a trailer, move it down the road. Hey, tornado zone ends over there! We're movin! No, instead they cluster up.

Re:Rednecks.

[Ngarrang]

I'm sure if they could afford better real estate, they would move. For some, yes, but 'home' can encompass more than just the 4 walls and the roof, or a postage-stamp yard. I grew up in the country with thousands of acres of farm landing surround me. It was nice. The air was clean, the environment was safe. The neighbors were pleasant. There is the sum total to consider and that very factor is what will keep people considering rebuilding on the edge of a volcano, next to a river, in tornado alley or next to the San Andreas fault.

Re:Rednecks.

[kv9]

It's still property, it's still their home. And they still lost it. *whoosh*

Re:Rednecks.

[zdickinson]

It's still funny, it's still not mean spirited, you're still stuffy.

Re:Rednecks.

[Anonymous Coward]

That *whoosh* was the sound of decency passing unnoticed by you.

Re:Rednecks.

[Talderas]

Build below sea-level in a hurricane region and near a river delta, expect a city to get flooded.

Re:Rednecks.

[Culture20]

It's a trailer, move it down the road. Hey, tornado zone ends over there! We're movin! No, instead they cluster up. I suppose the reason this person posted anon is because they new it was an illogical statement. Trailer homes don't move (they're not RVs), and there's no such thing as a "Tornado Zone". Cluster up? Tornadoes aren't really drawn to trailer parks; they just get damaged easier.

Re:Rednecks.

[Anonymous Coward]

I'M on a high horse? For what, pointing out how poor I've been? You're blaming the victim, calling them stupid for living where they do, making fun of the way they talk, discounting all the hardship and turmoil theses people go through, and I'M on a high horse? It's a very low high horse.

Re:Rednecks.

[omris]

as i say, mean plus funny still equals funny.

but in all honesty, i think that as a taxpayer in a non-tornado zone, it costs me much less to get them new houses occasionally than it costs me to help water every lawn in southern california, new mexico, and arizona, especially once you factor in the cost of repairing the damage done to the middle of the country when you steal all their water.

i am very anti-grass. sorry, but if you live in a desert, you should not have a pool. just my opinion.

Re:Rednecks.

[Gilmoure]

Let's look at the big picture: Natural Disaster Map.

Basically, looks like we're all screwed, trailer or not.

Re:Rednecks.

[oodaloop]

Yeah, and think about all those stupid morons who'll rebuild their homes after they're destroyed. Pfft. What idiots.

Re:Rednecks.

[Gilmoure]

After 2004 hurricane season in Florida (we had a bit of roof damage and some trees/fences down), I did a bit of research (have a much better natural disaster map at home buy my server's down; D'oh!) and we've resettled in the central New Mexico area. The only thing we have to worry about is mild chance of earth quakes and volcanos. We're close enough to the mountains that tornadoes don't form, far enough away to miss wild fires and heavy snow fall and there's no chance of flood, assuming someone doesn't drop a dino killer in the Indian ocean. We're also at high enough altitude that we don't have cockroaches, fleas, ticks, or fire ants. We do have bees, wasps, snakes and scorpions but that's about it for ouchy critters. Oh yeah, the year we moved out there, there was a lion hunting around our area, taking goats and chickens but there hasn't been a human killed by mountain lion since early 70's, though there was that kid that was attacked by something, hiking in the mountains. Still, with dogs, guns, and 40 acres of land outside of town, I feel pretty safe. Now, just have to get started on the bomb shelter.

Re:Rednecks.

[DerekLyons]

Yeah, I was appalled by the grandparent as well. It is always amazing to me how much bias is still tolerated, nay tacitly encouraged, here in the US. If the GP had used "nigger" or "faggot" instead of "redneck" - he'd have been modded 'flamebait' or 'troll' and his post soon forgotten down in the -5 basement.
 
But use "redneck" instead - and it's funny.

Re:Rednecks.

[Mr. Underbridge]

If they are on a hill - a mudslide. In the woods - forest fires.

Sorry, bud, but it's the rich folks in the Hollywood hills and the suburbs surrounding LA and San Diego that get hit most from those events. I realize that doesn't fit with your obnoxiously elitist premise, but there you go.

Re:Rednecks.

[Widowwolf]

Looks like I am moving to North Dakota..No natural disasters there..oh wait there's nothing at all there!

Re:Rednecks.

[Gilmoure]

Yeah. After posting, I also noticed that this map doesn't include flooding. Adds a whole 'nother color to it all. Pissed my home server's down. Have a great map I found online and can't find any more. Wonder why they're hiding it? Oh well, will post it later, after work.

Re:Rednecks.

[Anonymous Coward]

There's a difference between bigotry against choices people made vs bigotry against race and other biological facts. That said, it's still bigotry and a sign that someone is neither smart nor ethical.

Re:Rednecks.

[lavalamp70]

Growing up on 'tornado alley', every time a warning came on the tv we'd hold our breath waiting to see which county(s) were affected, then hope to hell it was not coming our way. Since someone mentioned the 'redneck' theory - and yes children I thought it was funny too - I might add that my family and I are not inbreeders nor rednecks. That being said, my parents current home sits in a subdivision where each home is on a one acre lot, and the home prices range from $500k to $1.5 million. In the ten years they have lived there, that subdivision has been hit twice. There's no mobile homes around. There's a ranch down the road that raises Thoroughbreds. It was hit both times. Living ANYWHERE in the plains states puts you at more risk for tornadoes than say Arizona. With the Gulf Stream - warm, moist air - moving north out of Texas, and the Jet Stream - cool, dry air - moving east, that's the general area where they collide touching off severe storms. It ain't rocket science .....

Accoustic detection- listen for

[Anonymous Coward]

The flying cows.

Re:Accoustic detection- listen for

[hcdejong]

That's why it's called "doppler": they detect the frequency shift in the "mooooooo"...

Wireless Internet?

[Anonymous Coward]

"The system is continuously diagnosing the atmosphere and reallocating resources using wireless Internet as a backbone,"
 
And by "wireless Internet" does he mean using people's unsecured wireless routers?

Re:Wireless Internet?

[lufo]

Not necessarily... just anything that could lose connectivity under severe weather condition.

Re:Wireless Internet?

[trooper9]

Ya. That was the first thing I thought about when I read the blurb: Wow. Wireless internet in severe weather. Whose great idea was this?

Re:Wireless Internet?

[arhhook]

Instead of wireless, they could use satellite internet with solar panels for power! Yeah...yeah!

Slow

[Wowsers]

Suppose that doppler radar is slow, and that it takes 5 seconds for it to do a 360 degree sweep. Is a faster system going to improve the generally rubbish weather forecasts of "it might rain today"?

Re:Slow

[MichaelSmith]

Suppose that doppler radar is slow, and that it takes 5 seconds for it to do a 360 degree sweep. Is a faster system going to improve the generally rubbish weather forecasts of "it might rain today"? If anything the slow rotation rate radar might be better for this application. Radars with short rotation periods are used in military applications where you need to see what is happening from second to second, and are increasingly being used in ATC applications.

But those radars need special software and hardware to deal with the fact that the returning signal is going to be coming from a significantly different azimuth (relative to the radar head) from where it was transmitted.

It is a lot of needless complexity and I really don't see why weather should need radars which rotate that fast.

Re:Slow

[mrbluze]

Is a faster system going to improve the generally rubbish weather forecasts of "it might rain today"? No, but someone is going to get a lot of grant money to implement it.

Re:Slow

[oodaloop]

I think we'll see what's going on now with more fidelity, but weather prediction is still limited by chaos. Weather is sensitive to initial starting conditions, so no matter how well we know those starting conditions (today's weather), we will not be able to predict future weather more than about 10 days out with any kind of fidelity. We've also noticed that some weather patterns are more chaotic than others. You may notice sometimes they say stuff like, "The hurricane will make landfall tomorrow morning at 2am here." And sometimes they say, "We really don't know what this storm is going to do. It could land tonight or blow north. We'll have to see." What they do is run several simulations using variables a few decimal places off. Sometimes they all do the same thing, sometimes they vary so much there's no way to know what's going to happen. Adding new radar will not change the fact that weather is inherently chaotic and unpredictable.

Re:Slow

[TigerPlish]

Is a faster system going to improve the generally rubbish weather forecasts of "it might rain today" No, nothing can help that. It's really tea-leaf reading.

What a faster system with a finer resolution will do is help better tell if that big nasty storm moving into your part of town will be an F1, or an F5 Magic Eraser.

It also will help stretch the warning leadtime. It's still not good enough.

Nexrad took the warning from pretty much after-the-fact to about +15 minutes these days. Nexrad, compared to the old-school FPS-77 and the like, is pixie dust.

The real clincher, not mentioned in TFA?

They're working on a phased-array replacement for Nexrad. Hit multiple individual cells at once. http://www.nssl.noaa.gov/research/radar/par.php

Re:Slow

[hcdejong]

When TFA says "slow", it's talking about 5 minutes, not 5 seconds. IDK why the update time is this slow, since 5 seconds is feasible even for a long-range radar (ie. 400 km).

Re:Slow

[clyde_cadiddlehopper]

In financial forecasting systems, the critical element is variance reporting. 'How wrong was yesterday's prediction?' leads to a sense of 'How much faith can you put in today's prediction?' Why, pray tell, is it that we NEVER see variance reports on the weather report?

Re:Slow

[giorgist]

At this point the best weather predictor is ...

"Tomorrow will be the same as today"

It beats the weather man by far and wide

G

Re:Slow

[CastrTroy]

The problem with weather forecasting is that they try to forecast way too far in advance. Checking out my local forecast, I see that they have until tuesday on the forecast. An entire week is too long to predict for weather. But they go further. There's now the 14 day trend. None of that is even worth looking at. I only trust the next day or two, and even that is a little fuzzy sometimes.

Re:Slow

[DarthBart]

The radars take several scans of the sky per "update".

They take scans at .5 degrees of dish elevation, 1.45 degrees, 2.4 degrees and 3.35 degrees. Those scans dissect the storm and look for rotation and intensity in different parts of the storm.

  Then the radars take an "echo tops" scan where the dish moves up and down to its limits while scanning horizontal. That lets the radars detect the total height of a storm, which gives another estimate of its strength.

So, its not just the dish spinning around in a single plane.

Re:Slow

[wakingrufus]

not in chicago our weather always changes, plus we have Tom FREAKING Skilling! he could have you killed if he wanted to.

Re:Slow

[DeadChobi]

Well, if you're an atmospheric scientist doing research into weather, a faster system gives you finer resolution for studying the kind of time-dependent systems that they're interested in. Don't assume that this system won't ever be used to collect scientific data to analyze. One of the advantages of a faster sampling rate is that you can make better predictions based on your data. Essentially, you have a better idea of where some deterministic system has been, and so if you have a pretty good idea of the principles under which it works you can then get a better idea of where it's going. Hell, even if we don't have a technique for making better extrapolations in the face of higher resolution data, someone somewhere will come up with a way.

The other useful thing about this kind of data collection ability is that it can also be used to improve models, especially if it has a better resolution for storm cells than the current doppler system.

Re:Slow

[afidel]

If you don't know why weather radar needs to be faster then you have never been watching during an active thunderstorm. Sweep periods are quite slow in high resolution mode, they can speed things up but it costs significant resolution loss. What is needed is synthetic aperture radar where you can point a small array of antennas at the storm and get multiple different elevation readings simultaneously. We've had the technology for quite some time but it's just now coming down in price to where we can think of using it broadly for weather stations.

Re:Slow

[hcdejong]

Interesting. Military radars usually do 3D scans by transmitting several beams at different elevations. Faster, but more expensive.

Re:Slow

[afidel]

With the current density of information collecting stations anything past about 10 days is just an educated guess, seven day forecasts are pretty darn accurate (generally getting precipitation chance and high and low temperatures to within a percent or two) with an additional three days being fairly accurate.

Re:Slow

[chaim79]

That really depends on the area, I have friends in areas where it's sunny 90% of the year with little variation in temps, for me, I'm in WI right next to the Mississippi, for us the weather changes every 6 hours or so.

Re:Slow

[afidel]

The meteorologists DO use variance reports to tweak their computer models and to select which model is currently the most accurate, but I can't imagine there are too many people that want that raw data.

Re:Slow

[Hatta]

5 seconds? We had a tornado here in Omaha a couple weeks ago, and the sirens provided no warning because it hit during the 5 minute blind spot in the radar. On one pass it was a severe thunderstorm, on the next pass it was a tornado on the ground.

If they can't make the radar rotate faster, they should add more dishes to the same radar so it's looking in 2 or 3 directions at once.

Re:Slow

[PMuse]

Is a faster system going to improve the generally rubbish weather forecasts of "it might rain today"? IMHO it's not so rubbish any more. Consider what we have now that we didn't have two decades ago.

1. Precipitation predictions now have an accuracy of about +-1 hour for every 6 or so hours looking forward. That is, predictions 6 hours out are +-1 hour, while predictions 3 days out are +-12 hours. At 10 days out you're at +- a day and a half, but two decades ago we had nothing, so that too is an improvement.
2. Temperature predictions are accurate to +-1 hour for every 6 as well.
3. Rather than one prediction for a metro area, we now get forecasts that differentiate the conditions by zip code or smaller area. (The shore where I work differs from inland where I live differs from the heights off to the east.)
4. Maps showing the next hour's weather update every few minutes, not once per day as previously. These maps tell with excellent accuracy the precise precipitation pattern and amount.

I suggest that general weather predictions are now quite good enough. Resources should be devoted to providing warning for deadly weather (tornadoes, floods, hurricanes) -- and they are.

Re:Slow

[tuxicle]

Surely you mean phased array radar, not synthetic aperture. The idea behind phased arrays is to improve overall volume scan times by allocating the limited energy budget of the radar as appropriate. Conventional radars, by design, will radiate an equal amount of energy over the entire scanned volume (over time). Phased arrays, given their ability to instantly (electronically) position the radar beam to any point in the sky, can allocate more energy to those areas that contain "interesting" targets (such as thunderstorms).

The DCAS part of CASA attempts to do this using multiple radars instead. So instead of each radar doing complete volume scans, a centralized system figures out where the "interesting" regions are, and directs the radars to scan only those sectors. The eventual plan is to use phased arrays at each radar node for even higher update rates.

Re:Slow

[tuxicle]

True, but only if you want to do target detection. If you want to make quantitative estimates about your target, you need to "dwell" longer, which pushes scan speeds up. Echoes from weather are generally weak, and weather radars need to estimate their properties. The slower you scan, the longer you dwell, and therefore, the estimates have lower variance. The trick is to get low variance as well as scan quickly.

Re:Slow

[tuxicle]

Also, by spreading smaller radars around, you observe stuff closer to the ground. This is typically missed by bigger radars such as NEXRAD, since the beams overshoot low-level features as you go further out in range.

Re:Slow

[Anonymous Coward]

The main problem with forecasting is the wide area of coverage. The storms that came through last week were like 100 miles long and 10 miles wide. That means half a town could have major weather, the other could be sunny. Now if you are broadcasting the weather report for that town what do you say? 50% of the town may get a 50% chance of rain? Or it could have covered the whole town, but one town over got nothing? Those are some of the realities of forecasting.

Re:Slow

[rubah]

That's because some people are interested in what will probably happen at that point. Weather patterns tend to repeat themselves year after year, so you can get a good average idea.

For example, in my hometown on a certain week of February, it usually goes up to 70 degrees for a few days. Someone from out of town probably wouldn't think to pack shorts for Arkansas in february, but they might end up wanting them.

Also, it has snowed on the same day in february almost every single year since 2002 (which was when I started counting, it might have been doing it before, I don't know xD).

There's nothing promising that the weather will do just that, but if you aren't familiar with a region, it's nice to have an idea of the recent year's trends.

Re:Slow

[Collective 0-0009]

Unless you live in south texas... It will be hot, high around 98, low around 76, cloudy and humid in the morning, burning off in the afternoon... for the next 3 months. Holy crap, I'm a god to the meterologist.

Re:Slow

[afidel]

You're correct, I was thinking about the improved imaging available to mobile applications through the use of phased array.

Aperture synthesis by post-processing of motion data from a single moving source, on the other hand, is widely used in space and airborne radar systems.wikipedia

The two concepts are related in that you use a phased array to implement synthetic aperture, but you would not typically use synthetic aperture for weather radar. I think it was the mention of multiple disparate antennas in the article that pulled up the memory banks on synthetic aperture.

Re:Slow

[skivvies]

Suppose that doppler radar is slow, and that it takes 5 seconds for it to do a 360 degree sweep. Is a faster system going to improve the generally rubbish weather forecasts of "it might rain today"? Exactly how much faster would you expect a 25' dish to rotate?

Re:Slow

[CastrTroy]

I was going to post something similar. It's easy to get the forecast right in certain areas, where the weather is generally the same every day (either no rain, or rain almost every day). In a lot of places, it's a lot harder to pinpoint exactly what the weather will be like on any particular day. If you look at the 7 day forecast for my region, the weather for the 7th day will probably change 3-4 times in most cases before the day occurs.

Re:Slow

[Kumba]

5 seconds? We had a tornado here in Omaha a couple weeks ago, and the sirens provided no warning because it hit during the 5 minute blind spot in the radar. On one pass it was a severe thunderstorm, on the next pass it was a tornado on the ground.

If they can't make the radar rotate faster, they should add more dishes to the same radar so it's looking in 2 or 3 directions at once. The Radar, even if it lacked the blind spot, can't determine if there's a tornado on the ground or not. It can only detect if there's a significant amount of rotation that makes conditions favourable for tornado formation, and then issue a TVS, or Tornado Vortex Signature. The forecaster reviewing the data has to then decide if the radar's predictions are worth issuing a warning. They have to consider data not only from the radar, but current weather conditions and perhaps from the most important source, people on the ground who spot storms and report them in.

This is why the NWS runs the National Skywarn program to help educate everyday people like yourself on how to look for certain signs of damaging storms, including severe and tornadic storms, and report them in so that the forecasters have solid data on conditions on the ground (which the radar can't see!).

http://www.skywarn.org/

Re:Slow

[tompaulco]

Here in Oklahoma we have Gary England. He actually had a cameo on Twister. One of the local radio stations has a tribute to him sung to the tune of the Hallelujah Chorus from Handel's Messiah. There's even a drinking game meant to go along with his live coverage during tornadoes.

Re:Slow

[tompaulco]

NEXRAD and CASA are not about long range predictions, and by long range I'm talking more than a few hours. These systems are designed to determine what is going on right now and what it means for nearby communities over the next short period of time.

Sydney Australia Radar

[z4ce]

Being an American in Australia, I was blown away to see that the highest resolution radar available for sydney is this:

http://mirror.bom.gov.au/products/IDR033.loop.shtml

At that resolution, the best way to see if you're going to get rain is pretty much to look out the window. A new radar tower is supposedly in the works, I hope they hurry up!

Re:Sydney Australia Radar

[Anonymous Coward]

If this CASA comes to Australia then we're going to have some miscommunication issues since CASA also stands for the (Australian) Civil Aviatiation Safety Authority http://www.casa.gov.au/

Re:Sydney Australia Radar

[MichaelSmith]

B At that resolution, the best way to see if you're going to get rain is pretty much to look out the window. A new radar tower is supposedly in the works, I hope they hurry up! I use the same information in Melbourne. I often check it before riding my bike home, but I don't see a benefit in better resolution. The few big storms we have really are big (not tornadoes) and you can't really expect to avoid them. Normally when it rains it just rains everywhere and again, the radar isn't going to help you much.

(-1)-bait

[Anonymous Coward]

Mi CASA es su CASA.

Title is misleading

[hcdejong]

because it suggests they'll use some new radar technology to replace doppler radar. In fact, they'll just install lots more radars (which can be cheap, short-range items) to improve coverage. According to the CASA site, they'll use modified marine navigation radars, ie the cheapest type of radar available, and these invariably are doppler radars.

This is new because?...

[NRISecretAgent]

You know, this might be wonderful and everything but I don't feel like I'm being technologically enlightened. They didn't explain how the new system actually works. Doppler pings the storm clouds and all that... this system doesn't? If it does then I can't see it being that much faster. And if you're looking at the wireless system to speed things up then you're crazy. The scanning has to get faster first unless you're going to stagger their scanning. And might I ask what happens when the tornado season really gets under way? Are you going to be replacing these things in the middle of the storm to make sure you don't lose your connection to the rest of the network?

Consumers need education on Doppler

[Anonymous Coward]

Hey It's cloudy outside I cant see the sun , that stupid Doppler radar doesn't show the clouds say many people Maybe this data is wrong or old
No it inst

  Doppler radar detects motion and in this case rain. The clouds simply have no falling rain in them.
You'll be surprised how many people don't know that Doppler radar does Not show clouds , it shows falling Rain ,
Maybe the weather service needs to educate he public better ?

Re:Consumers need education on Doppler

[dunc78]

First: You can detect stationary objects with a Doppler radar, just look at the zero Doppler components. The point of a Doppler radar is that you can distinguish between moving and stationary objects.

Second: Clouds are not stationary objects.

Re:Consumers need education on Doppler

[Anonymous Coward]

NEXRAD detects moisture concentrations (and the subsequent motion of moisture within the air). Even high humidity levels show some reflectivity. Bugs and birds and bats can be seen provided their numbers are concentrated enough.

Aging toddler

[Anonymous Coward]

Read that as "Replacement for aging toddler being tested".

I just died a little inside...

[E-Lad]

From the article:

The information is wirelessly transmitted to a central location over a 2-megabit-per-second DS3 connection. Sign me up for those wireless 2Mbit/s T-3s.

Re:I just died a little inside...

[afidel]

Yeah I think they confused DS3 with E1 =)

Summary wrong in pretty much every claim

[lakshmanok]

The summary statement gets things wrong in pretty much every respect, so this is mainly for those folks who read the summary and assume it's a fair reflection of the story.

(1) CASA is not designed to replace the existing NEXRAD network. It is designed to supplement it. NEXRADs are designed for long-range surveillance. CASA radars see "under" the NEXRAD umbrella, up to 3km in height. The article makes this clear.

(2) NEXRAD scans are not slow. The fastest volume coverage patterns (VCPs) in NEXRAD, used in severe weather, scan the atmosphere every 4 minutes. The only thing faster is phased array radar and it is still experimental (See: http://www.oar.noaa.gov/spotlite/). CASA radars don't have volume scans, but their antennas are about the same speed as NEXRAD's.

(3) NEXRAD is not limited in range. It goes up to 460 km. A CASA radar's range is only 30 km. If any one thinks that NEXRAD is "deeply flawed" due to its limited range, they need to take it up with the Flat Earth Society (the range limitation is mostly because of the earth's curvature).

Please make sure you understand an article before sending it off to Slashdot!

Re:Summary wrong in pretty much every claim

[Anonymous Coward]

Please make sure you understand an article before sending it off to Slashdot! You must be new here. ;-)

Re:Summary wrong in pretty much every claim

[TheHawke]

PAR systems have a bonus that CASA does not have: Active target tracking and targeting. You see, the SPY-1D system that is set up at NSSL Norman was pulled off of one of the Aegis nuclear-powered cruisers. Several advantages include graceful degradation. If something breaks on the panel, the system can adjust automatically to compensate, preventing an outage from knocking the unit out in case of a Major Event. One part breaks on the 99D's, game over until a tech gets out there to fix it. Another is no or few moving parts. PAR units are static, using electronic wizardry to steer the beam to the intended target. The other biggie is replacement or supplement for the ATC system. PAR's sensitivity and brute force have tracked targets at nearly over the horizon (OTH) range. That leads up the big item: cost savings on all fronts that need radar. Multitasking the beam can eliminate redundant installations, dramatically carving chunks off of budgets that can be used elsewhere.

NEXRAD's are aged, old units, and NOAA knows it. The klystron transmitter modules have been replaced more than once in the shacks and the rest of the hardware probably replaced or repaired several times over.

Even the military is looking into it.
http://www.roc.noaa.gov/eng/docs/Solid_State/Solid_State_Transmitter_PIWG_Brief.pdf

Re:Summary wrong in pretty much every claim

[RudeDude]

Your comments are helpful, but still not 100% accurate.

The rotation rate of the radar is faster and the volume updates are faster as well. CASA currently operates on a one minute "heartbeat" where many scans at different elevations are completed which cover a large portion of the total reachable volume.

While CASA radar does not provide a traditional "full volume" scan this is by design. For the first time we are dealing with a weather sensor that reacts to the environment automatically adjusting it's scanning pattern to be appropriate to the weather and follow storm paths.

CASA is running on a range much shorter than Nexrad. The current testbed is actually at 40 km range. The primary flaw or gap we are filling is the lower atmosphere which, as you stated, is due to the Earth's curvature and therefore a short range is most desirable.

The CASA radars are indeed full Doppler (not just marine radar) with dual polarization as well. They are currently mechanically steered but the technology under research will adapt quite easily to electronically steered beams from phased array radar panels as well.

As a side note the Nexrad system is indeed being upgraded in place to handle dual polarization which should improve snow detection and precipitation estimation.

Also "Super-res" is being deployed. This is a software change that makes the radar appear to have greater resolution by changing the way the signal is processed into smaller "bins". Literature seems to indicate this will help the human observer of the radar, but with the increased visual noise the algorithms will not see a significant improvement.

Full disclosure: I am a graduate research assistant working on the project.

Re:Summary wrong in pretty much every claim

[tuxicle]

Trouble with PARs is calibration. Military folks don't have to worry about that, but when one or more T/R elements fail on a PAR, how do you measure and compensate for that loss? With the SPY-1, it's relatively simple since it's a space-fed array, but for true active arrays, nobody's come up with a good solution to tackle the calibration issue. Worse, the sidelobe characteristics change when elements fail, and this would affect the antenna gain. How would you compensate for that?

There are some who pooh-pooh accurate calibration, but when you're looking at variations of 0.1 dB (for differential reflectivity), it becomes quite a challenge.

Navigation Radars != Doppler Radars

[dunc78]

Most marine navigation radars (Furuno, etc.) are not doppler radars. They are simple single pulse systems that need to be able to detect stationary objects such as buoys.

Doppler 4,000 super-max

[CottonThePirate]

I remember about 15 years ago all the news stations in my area upgraded their radars and would go on like used car salesmen about them: "Our radar is so powerful we can tell you where it's raining down to the square inch!". "Our radar will destroy their radar" and the like. I look forward to a new round of Doppler max 4,000 + eXtreme range boost.

So... If I'm a Tax Payer, Could I Say:

[general scruff]

Mi casa es su casa?

Local news

[Anonymous Coward]

That would be nice. Our local news channel is wrong 75% of the time. And their doppler radars usually only show 10% of the storm. I'd prefer a robotic weatherman who isn't late to the weather forecast every day. And when it's his turn to be on TV, he walks across his green screen without realizing he's on live TV. Wait, no... keep him. It's fun to watch. He once made fun of a specific race of people on live TV. Surprisingly didn't get fired... I talk too much, don't I?

And the NEXT next generation is called...

[Illbay]

...the Resolution Effect Array Longitudinal Radar.

Also known as REALRAD.

Super Resolution / RPG Build 10

[OceanWave]

This year, the NWS has started the installation of RPG Build 10. This, which also requires an upgrade of the network at the forecast office--will increase the resolution of the WSR-88Ds enough to essentially double the range.

Upgrade status: NWS Level II Radar Recieve Status

03 - Build 10 installed & the network updated to provide the LDM veed.
04 - Build 10 installed, but lacking the network upgrade. Data is derived to fit the legacy Level-II bandwidth.
NULL - Still Build 9, and no status of the network upgrade.

Reflectivity products will go from 1km bins x 360 radials to 250m bins x 720 radials. Velocity products will go from 250m bins x 360 radials to 250m bins x 720 radials. Range is increased to 300nm.

Common users will not see an improvement with the upgrade, unless they get a NEXRAD Level-II data feed. What you see on TV and the Internet are based on Level-III (more products, but much less resolution.)

Legacy Level-II to Level-III comparison: There are 4-bits resolution on Level-III products, whereas Level-II has 8-bits. Level-III doppler products are limited to 1km bins x 360 radials. (Build 11--next year--though maybe not publicly available, will introduce 5 new dual-polarization products, some having 16-bit resolution.)

The WSR-88D's still have quite a bit of life left in them... Granted, more nodes that have doppler products would be a big plus. But Super Resolution L-II data will give a big improvement.

Oh, Great

[gyrogeerloose]

We finally got doppler radar here in the San Diego area a few years ago--the last place in the nation because the NWS (justifiably) feels there isn't enough severe weather here to warrant it--and now it's obsolete already.

Damn, living in Paradise can be such a bummer sometimes...