|Apr29-12, 03:48 AM||#1|
Bizarre Oscillating Circles Above US
Greetings to all! I bring you all very strange and very peculiar tidings! I'll jump right into it:
Over the course of the last two days, a small group of friends have been examining what appears to be a collection of magnetic disturbances over the south-eastern region of the United States. These anomalies have been present for just over 48 hours, and appear over major cities (as well as several different satellites). Naturally I assumed they were the product of disturbances caused by doppler radars in the area, however, some circles have formed over areas where these radar towers are not present. This piqued my curiosity... even more so was the overall lack of information pertaining to this strange phenomenon.
Check out the picture and let me know what you guys think! Or if you've seen anything like it.
EDIT: Dates of pictures are between 4/27/12 and 4/28/12 (times will not be provided).
(The image above was a screenshot I took at: http://weather.cod.edu/satrad/index.php)
(The above close-up of one of the circles was taken at: http://www.accuweather.com/ Obviously I can't animate the images, but the circles appear to be rotating in opposite of each other, but at the same speeds. Upon closer zoom you can really see the intricacies. The 'calm' in the center of the circles is roughly 80 ± 5km (avg) in diameter. These stay put over the cities, and appear to oscillate or pulse synchronously with a matching frequency, which moves from the outer edges, inward (counter-intuitively). This also led to my theory that these were not produced by a wave-like objects originating at an epicenter. I have family living in Kansas City, where these disturbances have began to occur, and they say there is nothing but clear skies and gusts of wind that come from no discernible direction.)
(The above image was taken a day later at above the south-eastern region of the US: radar.weather.gov )
(continued: further west)
(With animation of the above image, you would see that the northern fronts break on the spheres like water on rock, and are mitigated away from the rest of the cells, also you can clearly see a pulsing quality they have. Also: http://weather.cod.edu/satrad/index.php )
My assumption is this could be either:
A) Is the result of some kind of disturbance on the radar.
B) A combined effort brought on somewhere in between the linking effects of heightened solar activity, the movement of the earths core, and it's direct effect on the magnetosphere. (which could be very bad for the new madrid fault line, located at the center of this activity)
Follow the above links if you wish to see this in action NOW! Pay close attention to the behavior of northerly bodies as they approach this southerly array of objects. I can't tell if the objects are being contained in the south by the coming wind, or if the northern lows are being pushed away by it, regardless, the objects are starting to form as far north as Illinois. If anyone has any idea what these might be, please let me know.
[EDIT: one more]
|Apr29-12, 04:32 AM||#2|
I don't see anything bizarre. Weather often comes in circles. That's due to the coriolis effect
Notice that the circular patterns in the radar maps are generally on the same place. That's the location of the weather radars. What you see is the radar range and I can imagine in heavy weather that the radar returns from longer range are more attenuated due to the strong reflections in closer range, giving the impression of circular weather.
|Apr29-12, 04:36 AM||#3|
Then how do we explain the rings that do not have radar towers in their proximity? Don't get me wrong, I'm not doubting. Also how would one explain the fact that there is visual confirmation that there are no clouds in the areas?
|Apr29-12, 06:49 AM||#4|
Bizarre Oscillating Circles Above US
That question is best asked to the providers of these maps.
|Apr29-12, 05:17 PM||#5|
As andre said around and in close to the radar reflections are very strong. You dont need visible clouds, just hi levels of water vapour aka hi humidity.
that and trees and other objects can cause all sorts of artifacts on weather radars
there are times you can even see swarms of insects or huge flocks of birds
|May1-12, 12:23 AM||#6|
I have been researching into this as well over the past few months. I typically check the radar daily in the summertime since we can get some wild thunderstorms out of the blue here in Oklahoma.
Each day as the sun sets, the dopplar radar stations light up with what appears to be ground clutter and sometimes the circling, concentric rings with the radar station at the center. I figure this is caused the humid surface air cooling down and the calibration of the stations picking up additional signatures.
So far I have found many theories on the cause of these radar anomalies.
This site has the best logical explanation:
This site goes a little off the spectrum (no pun intended):
|May1-12, 01:46 AM||#7|
So if it's a diurnal effect, the daily cycle in the ionosphere comes to mind.
|May1-12, 02:26 AM||#8|
I really have to point out that this is common with weather radars world wide
its NOT limited to the USA
|May11-12, 08:22 PM||#9|
The radar signal gets weaker as it travels out from the source as 1/r^2. The return from a radar pulse gets weaker vs distance as (1/r^2)(1/r^2), or 1/r^4 . So there is a strong correlation between the patterns on that map and the presence of a radar station - and that correlation is shaped like circles.
There are environmental variables like humidity which have time-of-day patterns. Nothing bizarre here.
|Jun15-12, 08:14 AM||#10|
Those circles are artifacts of the composite reflectivity radar product.
In addition, the cloudy objects you show in later images are the result of the WSR-88D running in something called "clear air mode".
I realize I'm late to the party on this one. I apologize if restate parts of what people have already said. I know this is a bit of a long post, so I've bolded the key points.
Part 1 -
Think of a NEXRAD doppler radar (WSR-88D)'s function in two ways. One, it spins around in a circle. Next, it can tilt up or down. A certain tilt is selected, and then the radar performs one circular spin to retrieve the data. The radar can then be tilted further up, and another spin can take place, etc... A radar operator knows how many "slices" of the atmosphere (tilt-levels of the radar) should be taken, depending on the weather conditions. Each of these modes is called a VCP, or a Volume Coverage Pattern. ( http://www.srh.noaa.gov/jetstream/doppler/vcp_max.htm ) ( http://okfirst.mesonet.org/train/nids/BREFguide.html )
In "clear air mode" the radar spins more slowly then in a mode where precipitation is expected, and therefore picks up on more detailed objects, particularly close to the radar. jdplant3d's link explains a lot of the common anomalies, like birds and dust, or nearby buildings and mountains. "Clear air mode" is useful in that it can also pick up dry lines, temperature inversions, smoke, and other information that is useful for providing a forecast.
If there's precipitation ocurring, it's important to know how fast it's moving, and just how much of it there is. You need updates quickly, so the radar is put into "precipitation mode". In this mode, the radar spins more quickly, but the data is not a detailed. Due to this, most of the anomalies visible in clear air mode are not present.
This is why when the National Weather Service data from each site is aggregated onto a large map, it looks like you have parts of the country with "normal" precipitation, and then all these wierd circles and blotches in the areas where it's not raining. If you watch an animation, it might even look like the rain is eating up or absorbing the blotches as it passes through! What's actually happening is that for each radar where it's not raining, they are running on clear air mode. When it starts raining, they switch to precipitation mode.
Above each radar site is a "cone of silence". This is an area that cannot be covered by the radar, since the radar can't tilt exactly upwards. This can also lead to strange appearances (and disappearances) on the radar graphics.
Another thing to know is that the atmosphere can also refract the radar beam depending on things like temperature and humidity, meaning that the beam is bent, and the percieved location of a radar feature can be incorrect. This can make for all sorts of strange things on a radar, like fast moving spikes and rain ghosts where it's not raining.
Part 2 -
There are two radar products that the NWS puts out: Base reflectivity, and composite reflectivity. Keep in mind that these are products - compilations and visual interpretations of the data collected by the radar.
Base reflectivity is just the lowest "slice" of the radar data. Composite reflectivity takes all of the slices, and for a given vertical column, and takes the highest value in that column.
This is why composite mode can sometimes show odd things like cocentric rings. The image in the inner ring is actually the exact same physical object or meteorological phemonenon as what's in the outer ring. An object is reflecting back for multiple radar sweeps, and the composite adds them together to show multiple features.
As far as your statement that some of the rings are in locations where there is no radar, I've looked at your maps, and they coincide with the locations of the NWS's NEXRAD installations. ( http://www.roc.noaa.gov/WSR88D/Maps.aspx ) In your top image, the circles are exactly centered around the KFDR (Frederick, OK) radar.
If you ever see a suspicious radar graphic, the best thing to do is to view it from another nearby radar.
If you were looking at the KFDR radar ( http://radar.weather.gov/radar.php?r...101111&loop=no ) and saw strange rings around Frederick, OK, and then switched to the KTLX radar ( http://radar.weather.gov/radar.php?r...101111&loop=no ) more than likely you wouldn't see the same rings around Frederick, OK.
If you'd like more information, a great free online course can be found here:
|Jun15-12, 12:45 PM||#11|
Case in point, the current situation around two radar sites in Oklahoma.
The FDR radar site shows the a cloud of "precipitation" around it, but nothing in Oklahoma city.
The TLX radar site shows a cloud of "precipitation" around it, but nothing back towards Altus.
Since we look at both radars, it's easy to intelligently decide which information is real and which data is anomalous.
There is a common feature between the two radars, the small thunderstorm south of Ardmore. There is also a small indicator of precipitation directly over Oklahoma City that's visible on the FDR radar but not TLX. It might be an anomoly, or (more likely based on size, shape, and persistence) it could be in the cone of silence for TLX.
Weather data aggregators around the web (Accuweather, etc) tend to take the individual radar data and patch them together into a quilt of graphics. Unfortunately, due to the fact that the radar anomalies aren't removed, it's possible to misinterpret them.
If we simply added the FDR and TLX sites together with some image editing software, it'd look like there was some really suspicious circular urban rain going on.
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