These are called "Polar Stratospheric Clouds" (PSCs). They form in the lower stratosphere when temperatures drop to around minus 85º C. This explains why they are rare; even at the poles, such low temperatures are hard to achieve. High-altitude sunlight shining through tiny (~10µm) ice particles in PSCs produce bright iridescent colors by diffraction and interference. Once thought to be mere curiosities, some PSCs are now known to be associated with the destruction of ozone. www.spaceweather.com
The stratosphere is a relatively clear layer of Earth's atmosphere, almost always cloud-free. Almost always. On Monday, researchers at Argentina's San Martín Base spotted a bank of fantastically colored clouds floating in the stratosphere above the Antarctic Peninsula: "There were the biggest stratospheric clouds we've seen so far this year," says photographer "Marcelo," who is working at the Base this winter. "It was a colorful spectacle to begin the day."
These are called "Polar Stratospheric Clouds" (PSCs). They form in the lower stratosphere when temperatures drop to around minus 85º C. This explains why they are rare; even at the poles, such low temperatures are hard to achieve. High-altitude sunlight shining through tiny (~10µm) ice particles in PSCs produce bright iridescent colors by diffraction and interference. Once thought to be mere curiosities, some PSCs are now known to be associated with the destruction of ozone. www.spaceweather.com
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Seaside photographers have a special fondness for the sunset. On rare occasions they can catch the elusive green flash--a split-second pulse of verdant light that signals the disappearance of the sun beneath the ocean waves. On April 7th, astronomy professor Jimmy Westlake photographed a green flash as he stood atop Hawaii's Mauna Kea volcano. The flash he saw, however, did not come from the ocean waves. It happened in the clouds: "The SKY Club from Colorado Mountain College got an emerald surprise," he says. "Several students visually witnessed the green flash while I was photographing it."
"This appears to be a cloud-top flash," says atmospheric optics expert Les Cowley. "They are not fully understood but might be produced by an inversion layer overlaying the clouds. We need more observations and associated weather data to understand them better." Basically, a temperature inversion bends the sun's rays to form a mirage that vertically magnifies the tiny color separation which is always present at the edge of the setting sun. Indeed,in Westlake's flash, we see not only green, but also yellow, red, and even a wisp of blue. "The intensity of the blue-green flash caught everyone by surprise!" says Westlake. www.spaceweather.com Strange Sounds : 26 Mar 2016 © Alfonso Topete Ramos This mysterious iridescent cloud fell from the sky just after the Stations of the Cross parade in Yago, Nayarit, Mexico.
CBS SF Bay : 18 Feb 2016 An annual pilgrimage by amateur and professional photographers to Yosemite National Park to capture a unique solar lighting effect has been revived with the recent wet weather.
For a couple of weeks in February, Yosemite's Horsetail Fall gets bathed in the light of the setting sun, creating what is known as a "firefall," with the waterfall and wet rockface creating an orange glow from the reflection. In recent years, a lack of water or cloudy weather has meant the spectacular effect does not appear during the brief window when the sun is aligned perfectly on the fall. This year, images of the firefall at Horsetail Fall has blanketed social media. The history of the Yosemite Firefall began with a manmade firefall in the last 19th century, when a campfire at the top of Glacier Point was pushed over the edge of the cliff, treating spectators below to a fiery spectacle. It became an annual event that increased in size and popularity, until it was finally discontinued in 1968. In 1973, close to the 100-year anniversary of the first Yosemite Firefall, a photographer captured the first known photo of the natural firefall at Horsetail Fall. Carlos E. Castañeda is Senior Editor, News & Social Media for CBS San Francisco and a San Francisco native Patrick Knox : Daily Star (UK) : 27 Jan 2016 © MERCURY A cloud that took the form of a 'hand of God' holding a fireball dominated the skyline above the north coast of the Portuguese island of Madeira. And weather blogger Rogerio Pacheco, 32, could not believe his luck when he looked up at the clouds while commuters made their way to work in the morning rush hour.
The awe-inspiring snaps have since been shared online after Rogerio opted to post them on his blog. Amazed onlookers have compared the bright orange cloud to everything from a flaming fist of fury to the iconic comet featured in the classic video game Final Fantasy VII. Rogerio said: "As soon as I saw the sky, I was immediately intrigued and I just had to grab my camera to take a photo. For me, the cloud looks like an outstretched hand with a fireball. I was not the only one who seemed to notice it and I could see other people also looking up at the sky. A lot of people seemed pleasantly surprised when they looked up at the sky and saw the cloud." Strange Sounds : 20 Dec 2015 If you have ever been privy to the phenomenon of light pillars, then you know it is truly an amazing sight. They appear when the weather is extremely cold and form vertical columns of light beaming directly towards the sky. Here a compilation of pillars of light for December 2015. They sometimes look like multiple fireballs heading to the sky:
Geomagnetic storms are brewing, but not every colorful light in the night sky is an aurora. For instance, Yuri Beletsky sends this picture taken Dec. 17th from the Atacama desert in Chile: "These are not auroras. We just witnessed an amazing display of airglow," says Beletsky. "It was so intense that you could not see many stars close to the horizon - the sky was literally shining."
Airglow is an aurora-like phenomenon in the upper atmosphere caused by a variety of chemical reactions. It begins during the day when solar ultraviolet radiation ionizes atoms and molecules. At night, those same atoms and molecules glow as they re-capture lost electrons. The green in Beletsky's photo comes from oxygen atoms in a layer 90-100 km high; the red is probably associated with OH ions at an altitude of about 85 km. The wavy structure of the glow is due to high-altitude gravity waves, which alter the temperature and density structure of the upper atmosphere. "Airglow is much less intense than aurora," continues Beletsky. "The display I saw looked, to the naked eye, like a series of black-and-white waving bands. The full color of the display was easily captured, however, by my digital camera." www.spaceweather.com For the second day in a row, sky watchers are reporting an outbreak of polar stratospheric clouds (PSCs) around the Arctic Circle. Unlike normal grey-white clouds, which hug Earth's surface at altitudes of only 5 to 10 km, PSCs float through the stratosphere (25 km) and they are fantastically colourful. Truls Tiller photographed these over Tromsø, Norway, on Dec. 16th: "Here the sun is gone for now," says Tiller, "but this beautiful view makes the winter darkness nice to be in as well. The picture was taken at 10.30 am, in the middle of the 'day.'"
Also known as "nacreous" or "mother of pearl" clouds, the icy structures form in the lower stratosphere when temperatures drop to around minus 85ºC. High-altitude sunlight shining through tiny ice particles ~10µm across produce the characteristic bright iridescent colours by diffraction and interference. Once thought to be mere curiosities, some PSCs are now known to be associated with the destruction of ozone. "Nacreous clouds far outshine and have much more vivid colours than ordinary iridescent clouds, which are very much poor relations and seen frequently all over the world," writes atmospheric optics expert Les Cowley. "Once seen they are never forgotten." www.spaceweather.com Before Its News : 16 Sep 2015 On September 15, 2015, witnesses filmed a very strange cloud phenomenon above Costa Rica at about 3.00 pm local time. We may wonder whether this strange cloud is just a natural phenomenon or a so-called earthquake light or there's more than our eyes can see? Earthquake lights are reported to appear while an earthquake is occurring, although there are reports of lights before or after earthquakes. They are reported to have different shapes with a white to bluish hue, but occasionally they have been reported having a wider color spectrum. The luminosity is reported to be visible for several seconds, but has also been reported to last for tens of minutes.
A different explanation involves intense electric fields created piezoelectrically by tectonic movements. Another possible explanation is local disruption of the Earth's magnetic field and/or ionosphere in the region of tectonic stress, resulting in the observed glow effects from ionospheric radiative recombination at lower altitudes and greater atmospheric pressure.
Aurora Borealis 9-12-14 from Lights Over Lapland Plus
On September 11th and 12th two CMEs interacted with Earth's magnetosphere, causing a KP-7 Geomagnetic storm. The storm sparked large aurora displays that will never be forgotten by the people that were lucky enough to witness the event. This short film is for everyone else.... facebook.com/lightsoverlapland Frequent fliers who look out the window of their planes often see the shadow of the aircraft dipping in and out of clouds below. The interplay of light and shadow with water droplets in the clouds can produce colorful rings of light called "glories." On July 13th, Tony DeFreece saw a glory that was not a colorful ring, but rather a heart: "I was flying over Oregon when I looked out and saw this heart-shaped figure," he says. "It was one of those moments when the Universe aligns and takes your breath away."
DeFreece suspects, probably correctly, that the shape of the clouds bent the usual circular glory into the heart-shaped apparition. Mystery solved? Not entirely. Glories are caused by sunlight reflected backwards from water droplets in clouds. Exactly how backscattering produces the colorful rings, however, is a mystery involving surface waves and multiple reflections within individual droplets. Each sighting is a lovely puzzle, so grab the window seat and keep an eye on the clouds below. http://spaceweather.com/ ![]() Around the northern hemisphere, sky watchers are starting to report a rainbow-colored sun halo that appears almost-exclusively during summer: the circumhorizon arc. "I saw one on June 13th. It was very bright," says Michail Anastasio, who snapped this picture from the cockpit of a plane flying 20,000 feet over Singapore: Nicknamed the "fire rainbow" because of its fiery rainbow colors, this apparition in fact has nothing to do with either fire or rainbows. It is caused by sunlight refracting through plate-shaped ice crystals in cirrus clouds. The geometry of the refraction requires that the sun be high in the sky (above 58o), which explains why this is a summertime phenomenon. June and July are the best months to see circumhorizon arcs. Look for them circling the horizon sometimes in patches, sometimes not, always brightly decorated with pure and well separated prismatic colors. You'll know it when you see it. http://spaceweather.com/ "We are enjoying one of our best years ever," reports Chad Blakley, an aurora tour guide in Sweden's Abisko National Park. "So far we have seen auroras on 29 out of the 31 nights we have looked. Last night was extra special. The sky exploded in color and I was lucky to capture the phenomenon with several different cameras from multiple angles." Click to view the resulting footage: "The lights were so powerful that the images became overexposed with a shutter speed of less than one second," he continues. "I can honestly say that this was one of the greatest displays of natural beauty that I have ever seen."
The show is apt to continue tonight. NOAA forecasters estimate a 25% chance of geomagnetic storms on Feb. 3-4 when an approaching CME is expected to deliver a glancing blow to our planet's magnetic field. www.spaceweather.com Taken by hundreds of people around the world, the pictures of Comet ISON we receive every day vary widely in quality, context and camera settings. However, they all seem to have one thing in common: the comet looks green. Why? To answer this question, Italian amateur atronomers Paolo Corelli and Dario Comino used a high-dispersion spectrometer to analyze light from the comet's atmosphere. Here are their results: The spectrum of Comet ISON is dominated by a green spectral line from diatomic carbon (C2). This substance is common in the atmospheres of comets, and it glows green when illuminated by sunlight in the near-vacuum of space. The spectrum also shows a weaker but still significant blue emission line from C2. Comet ISON's mixture of green and blue light gives it the aqua hue seen in many long-exposure photographs. Finally, the spectrum reveals a contribution from atomic oxygen. This element is familiar to readers of spaceweather.com as a source of green light in auroras. www.spaceweather.com
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