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Radar can see individual raindrops from 2 km

Most people are familiar with radar imaging of storms from local news broadcasts and all the interruptions to your favorite programming during bad weather. The radar most of us are familiar with offers limited resolution when it comes to seeing what's actually going on inside the storm. The U.S. Navy, however, has a new high-resolution radar that offers vastly improved imaging capability.
The U.S. Naval Research Laboratory recently announced the Navy has a very high resolution Doppler radar that can actually see into a storm and image individual raindrops in the cloudburst. The breakthrough opens the door for improved monitoring applications that can be able to track and monitor weather and severe storms with significantly more accuracy.
"Similar to the traces left behind on film by sub-atomic particles, researchers observed larger cloud particles leaving well-defined, nearly linear, radar reflectivity "streaks" which could be analyzed to infer their underlying properties," NRL stated.
The Naval Research Laboratory used this "mid-course radar" to retrieve information on internal cloud flow and precipitation structure. The radar has been used in the past to track small debris shed during space shuttle missions during launch. It has the capability of imaging a cloud with the volume roughly equal to the small bus at a range of 2 km.
The researchers believe that the radar could help unlock the mysteries that are still unknown having to do with cloud and precipitation formation. These mysteries include things like the development and movement of large hail stones that cause billions of dollars in damage annually to crops and property in the United States. 

Source: Network World

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Seeing shadows
By DennisB on 6/29/2012 9:30:29 AM , Rating: 3
Actually, water absorbs most electromagnetic waves so we see shadows. Is also the reason radio doesn't work under water. Something basic, some engineers seem not to realize they couldn't use GPS under water.

Anyway, does this mean we can catch fairies now? lol

RE: Seeing shadows
By MrBlastman on 6/29/2012 9:46:29 AM , Rating: 2
Like all things in science, one cannot ever profess to know everything:

From the NRL: "Scientists could detect the individual particles because of a combination of the radar's 3MW power, narrow 0.22 degree beamwidth, and an unprecedented range resolution as fine as 0.5m. This combination of radar attributes allows researchers to sample a volume of cloud about the size of a small bus (roughly 14 m3) when operating at a range of 2 km. With such small pulse volumes, it becomes possible to measure the properties of individual raindrops greater than 0.5mm in diameter due to the low concentration of such drops in naturally occurring cloud systems and the overwhelming dominance such drops have on the measured radar reflectivity when present in a field comprised of smaller particles. "

Remember, the albedo of water increases dramatically at high angles of incidence and this holds true for various wavelengths, okay, certain ones outside of the visible spectrum.

RE: Seeing shadows
By JKflipflop98 on 6/29/2012 11:22:44 AM , Rating: 2
Radio waves move just fine underwater. It just depends on your frequency.

RE: Seeing shadows
By Natch on 6/29/2012 1:54:44 PM , Rating: 3
Yep. US Navy subs can receive radio signals through the ULF (ultra low frequency) radio system. This prevents them from having to surface every so often, in order to check for radio traffic.

There's even a sub to sub "phone" system, that allows one boat to call another one, though the range is short (and I don't profess to understand how it works, so not 100% sure it's electromagnetic waves).

So far as GPS goes, the subs get a fix before they submerge, then use dead reckoning to calculate where they are, while under water. Upon surfacing, prior to launching air delivered weapons (i.e. - Tomahawk cruise missiles or, Heaven forbid, ICBM's), they'll do a quick GPS fix, and feed the updated information into their fire control systems, in order to confirm their location.

RE: Seeing shadows
By Smilin on 6/29/2012 2:41:57 PM , Rating: 2
While I'm sure they are conducting dead reckoning as a backup the primary navigation underwater is INS. Unlike with aircraft they can use a pretty heavy and accurate INS.

RE: Seeing shadows
By MrTeal on 6/29/2012 5:37:53 PM , Rating: 2
Umm... An INS is dead reckoning. You have your starting position and you use your INS to chart your path with no external fixed reference.

RE: Seeing shadows
By Icebain on 6/30/2012 10:46:10 AM , Rating: 3
UWT system uses a sonar based system, not radio. (Underwater Telephone = UWT)

Source : Submariner (me)

Also, with GPS, we don't need a fix prior to firing, but I'm not allowed to get into that.

RE: Seeing shadows
By lexluthermiester on 7/1/2012 10:41:34 PM , Rating: 2
Also, with GPS, we don't need a fix prior to firing, but I'm not allowed to get into that.

However, the system does require an occasional recalibration/calibration verify, which requires a surface operation. Of course this may no long be the case as advances in technology progress...

RE: Seeing shadows
By Amiga500 on 7/2/2012 8:09:01 AM , Rating: 2
Also, with GPS, we don't need a fix prior to firing, but I'm not allowed to get into that.

Well, its quite rudimentary and not exactly top secret. Once the missiles are in the air, they can fix themselves, after all, they do have the GPS equipment anyway for navigation.

RE: Seeing shadows
By Icebain on 7/2/2012 1:57:28 PM , Rating: 2
It is classified and doesn't use GPS at all. All it takes is one atmospheric nuclear blast to knock out all GPS systems.

RE: Seeing shadows
By DennisB on 7/2/2012 6:18:37 PM , Rating: 2
Ballistic ones use astro navigation in addition to GPS. Achaic systems are quite popular when modern things don't work. ;)

Now-a-day we got gravity maps aside from the magnetic maps as well as new sonar stations. That's fairly good enough for a sub.

Such secrets are known by experts anyway, so what's the point to keep low level information?

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