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US Navy's High-Resolution Radar Can See Individual Raindrops In a Storm 161

Posted by samzenpus
from the needle-in-a-haystack dept.
coondoggie writes "The U.S. Naval Research Laboratory (NRL) researchers said recently that a Navy very high-resolution Doppler radar can actually spot individual raindrops in a cloudburst, possibly paving the way for new weather monitoring applications that could better track or monitor weather and severe storms. According to an NRL release, the very high-resolution 'Mid-Course Radar' was used to retrieve information on the internal cloud flow and precipitation structure. The radar was previously used to track small debris shed from the NASA space shuttle missions during launch. '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."
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US Navy's High-Resolution Radar Can See Individual Raindrops In a Storm

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  • by bmo (77928) on Friday June 29, 2012 @02:40AM (#40491159)

    >Doppler radar can actually spot individual raindrops in a cloudburst,

    A raindrop, you say? Like what, a big one? Ok, that's 5mm across for the largest type. From here: http://hypertextbook.com/facts/2001/IgorVolynets.shtml [hypertextbook.com]

    It's only a matter of time that other countries develop "weather radar" as pinpoint as this.

    The F22 and F35 radar cross sections have been compared to a metal marble and a metal golf ball, respectively. Their "stealth technology" has just been rendered obsolete.

    --
    BMO

  • by Chrisq (894406) on Friday June 29, 2012 @03:40AM (#40491393)

    Detecting a stealth aircraft and being able to identify what you've detected as a stealth aircraft are two completely different animals.

    I think that any "marble sized" object travelling near mach-1 would be suspicious

  • Re:useful.... (Score:5, Insightful)

    by rtb61 (674572) on Friday June 29, 2012 @08:34AM (#40493021) Homepage

    What it means is stealth is now meaningless technology, paying megabucks for a stealth fighter is simply throwing the tax payers money away. Once you can accurately track moisture in the atmosphere, then tracking ex-stealth aircraft is simply a matter of searching for and pinpointing areas of the sky not behaving like other areas of the sky. Specifically those areas of the sky which show a disturbance of where the aircraft has been, contrails http://en.wikipedia.org/wiki/Contrail [wikipedia.org] and where the aircraft actually is shock and compression waves http://en.wikipedia.org/wiki/Shock_wave [wikipedia.org], even subsonic compression of the atmosphere by the passage of an aircraft substantially alters the amount of moisture in close proximity to the aircraft.

    The US Navy might as well announce to the world, don't waste your money on the F35 or F22, what you want is a high durability aircraft. Stealth is utterly meaningless especially when the shape impacts durability and performance. Basically the only real defence is flying really low, as fast as possible and being the smallest target possible (cruise missile). Once you get above ground clutter, you'll announce your position, even if you stop and hover, your past passage will show up as well as your thrust plumes, jet or propeller.

    No such thing as 'atmospheric' stealth no matter how advanced your technology unless of course you can jam or shut down the detection technology with even more 'advanced' technology (you can guess who I mean), the microchip being such an desirable target for at range energy fluctuations.

  • Re:useful.... (Score:4, Insightful)

    by tnk1 (899206) on Friday June 29, 2012 @09:09AM (#40493447)

    This may not yet be useful for real-time air defense purposes. The actual equipment my not be field mobile. Not to mention that getting data and analyzing over time it is one thing. Doing that while an aircraft comes at you at Mach 1.2 is a little different. Especially when it has a bomb or an anti-radiation missile with your name on it.

  • by cpotoso (606303) on Friday June 29, 2012 @09:50AM (#40493987) Journal
    Unless you have a radar wavelength smaller than the size of a raindrop (\lambda 0.5 mm seems far-fetched), then you CANNOT SPOT INDIVIDUAL RAINDROPS. Furthermore, to achieve the kind of ANGULAR RESOLUTION required, would necessitate a HUGE-sized dish given that roughly speaking the diffracion limit is \Delta \theta ~ \frac{\lambda}{D}, where D = diameter of the dish. What the article says is that you can understand the size and distribution of MANY small raindrops in a cloud, which presumably before you could not. I am amazed how little basic physics /.-tters seem to know.
  • Re:useful.... (Score:4, Insightful)

    by Baloroth (2370816) on Friday June 29, 2012 @10:47AM (#40494757)

    Scientists could detect the individual particles because of a combination of the radar's3MW 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.

    In other words, if you know where the stealth aircraft is to within the region of a small bus, this thing can find it!...so long as it isn't more than 2km away.

    This radar is completely worthless in finding a stealth aircraft, or any aircraft at all for that matter. As presented, it doesn't even have any uses for that at all. Maybe you could extend it to that, but the narrow bandwidth and high power means it will be pretty well worthless for stealth detection.

Somebody ought to cross ball point pens with coat hangers so that the pens will multiply instead of disappear.

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