Photographer Reyaz Limalia took photos of an optical phenomenon known as "ice rainbow" near Birdlip, UK
The optical phenomenon a “22 degrees halo” because of its circular formation of 22 degrees around the sun.
A 22° halo is a halo, a type of optical phenomenon, forming a circle 22° around the sun, or occasionally the moon. It forms as sunlight is refracted in hexagonal ice crystals suspended in the atmosphere. As the light beam passes through two sides of the prism forming a 60° angle, the angle of minimum deviation is almost 22° (namely, 21.84° on average; 21.54° for red and 22.37° for blue). This wavelength-dependent variation in refraction causes the inner edge of the circle to be reddish while the outer edge is bluish. A 22° halo may be visible on as many as 100 days per year, depending on latitude.
The light passing through these hexagonal ice prisms are deflected twice, which then produces the deviation angles ranging from 22° to 50°. Lesser deviation results in a brighter halo along the inner edge of the circle, while greater deviation contribute to the weaker outer part of the halo. As no light is refracted at smaller angles than 22° the sky is darker inside the halo. This effect is similar to Alexander’s Band, which lies between primary and secondary rainbows.
22° halos form when the sky contains millions of variously oriented (poorly correlated) ice crystals. Some of these happen to be aligned perpendicular to the sun’s light as viewed by any given observer, which produces the illuminated 22° circle, while other crystals produce the same phenomenon for other observers.
Like other ice halos, 22° halos appear when the sky is covered by thin cirrus clouds containing the ice crystals that cause the phenomenon. Small colourful coronas much nearer the sun produced by water droplets can occasionally be confused with 22° halos.
WeatherVortex.com/blog posts ©2010 McGuinnessPublishing All Rights Reserved World Wide
Also be sure to visit our other Unique World Websites:
A pileus (pronounced /ˈpaɪl.i‿əs/, Latin for cap), also called scarf cloud or cap cloud, is a small, horizontal cloud that can appear above a cumulus or cumulonimbus cloud, giving the parent cloud a characteristic “hoodlike” appearance. Pilei tend to change shape rapidly.[citation needed] They are formed by strong updrafts acting upon moist air at lower altitudes, causing the air to cool to its dew point. As such, they are usually indicators of severe weather, and a pileus found atop a cumulus cloud often foreshadows transformation into a cumulonimbus cloud, as it indicates a strong updraft within the cloud.
Pileus forming over the ash cloud from the eruption of Sarychev Peak
Clouds that are attached to pilei are often given the suffix “pileus” or “with pileus”. For example, a cumulonimbus cloud with a pileus attached to it would be called “cumulonimbus with pileus”.
Pilei can also form above ash clouds and pyrocumulus clouds from erupting volcanoes (see the image to the right).
Pilei form above some mushroom clouds of high-yield nuclear detonations; in that context they are called ice caps.
Pileus on a Cumulus cloud
WeatherVortex.com/blog posts ©2010 McGuinnessPublishing All Rights Reserved World Wide
Also be sure to visit our other Unique World Websites:
Cold Front, Warm Front - coutesy of NASA
Weather fronts are as familiar as rain. For those who live outside of Earth’s tropics, the movement of warm and cold masses of air creates the weather, and when the two clash, it often rains. Understanding what happens when cold and warm air meet (cold and warm fronts) has given meteorologists the ability to predict the weather.
But for all of their familiarity with fronts, scientists have only recently gotten a detailed view of them. These four images contrast computer models of weather fronts (lower images) with the view from NASA’s Cloudsat (top), a space-based radar. The radar instrument on the satellite provides a detailed view of the cloud structure and precipitation in the clouds, helping scientists refine their understanding of common weather patterns and improve their ability to predict the weather.
The left image pair shows a cold front moving from left to right into a warm mass of air. The cold, dense air lifts the warm air like a wedge. The rising, warm air forms distinctive anvil-shaped clouds, visible in both the satellite and model image. Along the leading edge of the front, the rising air can develop into intense thunderstorms with heavy bursts of rain if there is enough moisture in the air.
Rain droplets send a stronger radar signal back to the satellite. This means that areas of heavy rain are dark blue, while lighter rain is lighter in color. The Cloudsat image shows a single area of concentrated rain surrounded by a line of lighter rain. The less detailed model shows a broad swath of rain. Cloudsat also reveals a line of low, rain-producing clouds behind the front that the model missed.
The right image pair shows a warm front moving from left to right over a cold mass of air. In this case, the lighter, warmer air lifts gradually over the cold air. The rising air cools and condenses into a wide area of clouds and steady rain. While both the satellite and the model detect the rain (shown in dark blue), Cloudsat shows more rain over a wider area.
Cloudsat launched on April 28, 2006, and began to take measurements a little over a month later. The moment the satellite turned on, its first image showed the structure of both a cold front and a warm front in detail scientists had never seen before. In the five years since, the instrument has provided numerous observations of cloud structures, from the unusual—hurricanes—to the mundane, common fronts.
WeatherVortex.com/blog posts ©2010 McGuinnessPublishing All Rights Reserved World Wide
Also be sure to visit our other Unique World Websites:
Noctilucent Clouds
Noctilucent Clouds
After the Sun sets on a summer evening and the sky fades to black, you may be lucky enough to see thin, wavy clouds illuminating the night, such as these seen over Billund, Denmark, on July 15, 2010. Noctilucent or polar mesospheric clouds, form at very high altitudes—between 80 and 85 kilometers (50–53 miles)—which positions them to reflect light long after the Sun has dropped below the horizon. These “night-shining” clouds are rare—rare enough that Matthew DeLand, who has been studying them for 11 years, has only seen them once in person. But the chances of seeing these elusive clouds are increasing.
WeatherVortex.com/blog posts ©2010 McGuinnessPublishing All Rights Reserved World Wide
Also be sure to visit our other Unique World Websites:
Lightning Over Brazil - Image Credit: ESA/NASA
The European Space Agency’s Paolo Nespoli took this image of lightning over Brazil as seen from the International Space Station in January 2011. Nespoli, a member of the Expedition 27 crew, first visited the station in 2007 as a member of the STS-120 crew aboard space shuttle Discovery to deliver the Italian-built Harmony node.
WeatherVortex.com/blog posts ©2010 McGuinnessPublishing All Rights Reserved World Wide
Also be sure to visit our other Unique World Websites:
Ozone Hole through the years
Ozone is Earth’s natural sunscreen, shielding life from excessive amounts of ultraviolet radiation. But Earth’s ozone layer has been damaged by well-intentioned chemicals—chlorofluorocarbons, used for refrigerants and aerosol spray-cans—that have the unintended consequence of destroying ozone molecules.
In the late 1980s, governments around the world woke up to the destruction of the ozone layer and negotiated the Montreal Protocol, an international treaty to phase out ozone-depleting chemicals. The treaty included a requirement that scientists regularly assess and report on the health of the ozone layer, particularly the annual Antarctic ozone hole. In January 2011, the Ozone Secretariat of the United Nations Environment Programme released its latest report and noted that the Protocol has “protected the stratospheric ozone layer from much higher levels of depletion…[and] provided substantial co-benefits by reducing climate change.”
This series of images above shows the Antarctic ozone hole on the day of its maximum depletion in four different years; that is, the days with the thinnest ozone layer as measured in Dobson Units (DU). The measurements were made by NASA’s Total Ozone Mapping Spectrometer (TOMS) instruments from 1979–2003 and by the Royal Netherlands Meteorological Institute (KNMI) Ozone Monitoring Instrument (OMI) from 2004–present. Purple and dark blue areas are part of the ozone hole.
On September 17, 1979 (top left), the first year in which ozone was measured by satellite, the ozone level was at 194 Dobson Units. On October 7, 1989 (top right), the year that the Montreal Protocol went into force, ozone dropped to 108 DU. On October 9, 2006 (bottom left), ozone measured 82 DU. By October 1, 2010, the value was back up to 118 DU.
The lowest value (deepest hole) ever recorded was 73 Dobson Units on September 30, 1994, while the broadest hole occurred on September 29, 2000, when the ozone-depleted area stretched 29.9 million square kilometers. The record for mean size of the ozone hole—the greatest extent over a one-month window—was September 7 to October 13, 2006, when the hole reached 26.2 million square kilometers. The mean ozone hole in 2010 was 22.2 million square kilometers.
In their 2010 report, the science advisers to the Montreal Protocol found that:
- Global ozone and ozone in the Arctic and Antarctic is no longer decreasing, but is not yet increasing.
- The ozone layer outside the Polar Regions is projected to recover to its pre-1980 levels some time before the middle of this century. The recovery might be accelerated by greenhouse gas-induced cooling of the upper stratosphere.
- The ozone hole over the Antarctic is expected to recover much later.
- The impact of the Antarctic ozone hole on surface climate is becoming evident in surface temperature and wind patterns.
- At mid-latitudes, surface ultraviolet radiation has been about constant over the last decade.
WeatherVortex.com/blog posts ©2010 McGuinnessPublishing All Rights Reserved World Wide
Also be sure to visit our other Unique World Websites:
Cloud vortices off Isla Socorro, North Pacific
The cloud cover of the North Pacific Ocean was decorated with lacy swirls and bold stripes on May 11, 2011, when the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite flew over the region and captured this true-color image.
Cloud patterns are beautiful to behold, but formations within cloud cover have more in common with cryptographs than pure art. Each swirl, stripe and even the color of a cloud reveals a story for those who know how to read such patterns.
The most striking pattern in this image is the string of repetitive vortices that trail southwards from the green Isla Socorro. This formation, known as a Karman vortex street, reveals turbulent wind flow. From the direction that the pattern lies across the sky, it is clear that a strong wind blows southward. As the wind slams against abrupt rise of the 1,050-meter-tall summit of the volcanic island, it lifts up and is blown around either side of the obstruction, causing a turbulent flow. This is first revealed where the cloud cover ends in a sharp arc around the front of the island. Then the wind behind the island flows in repetitive swirls, much like eddies formed on a strong inflowing tide that runs against a dock’s piling, and the swirling pattern of the clouds reveal the swirling path of the wind.
To the northeast of Isla Socorro, the clouds form a sharp stripe across the sky. Here the strong southward-flowing wind encounters the tiny Isla San Benedicto, whose tallest peak, at 332 meters, is tall enough to obstruct the flow, but not big enough to cause the swirling turbulence formed behind the bigger mountain. Instead, the wind ripples around the island in a cloud-free V-shape, then bright white clouds reform along a southward flow directly behind the island.
Most of the cloud cover in the image appears dull white which tends, in some area, to light gray. This coloration is revealing, as well. Clouds are formed when many tiny droplets of water or ice condense around a nucleus. These tiny droplets are packed tightly together, and reflect all visible wavelengths of sunlight. Because of the wavelengths reflected, the color appears white. Because of the tiny size of the droplets, the reflectivity is high and the white appears very bright.
When tiny droplets in clouds begin to merge with others, a process called accumulation, the space between each droplet becomes larger, allowing the cloud to absorb more light. Because of the increased light absorption, the reflectivity is less, so a cloud made up of large droplets can appear dull white. As this accumulation continues, the diminished reflectivity can result in clouds that appear gray.
WeatherVortex.com/blog posts ©2010 McGuinnessPublishing All Rights Reserved World Wide
Also be sure to visit our other Unique World Websites:
Massive Saudi Arabian Sand Storm stretches more than 500 kilometers (300 miles)
A dense wall of dust barreled across the Arabian Peninsula on March 26-27, 2011. The massive storm stretches more than 500 kilometers (300 miles) across the peninsula, covering parts of Saudi Arabia, Yemen, Oman, and the United Arab Emirates.
On March 26, the storm stops short of Oman and Yemen, and the opaque mass of dust is bordered by crystal-clear skies to the south. Some plumes blow across the Persian Gulf toward Iran. The following day, the dust has moved southward, and is especially thick over Yemen.
According to local news reports, the storm started in the late afternoon on March 25 in Iraq and Kuwait. The fast-moving storm dropped visibility to near zero, cloaking Kuwait in premature darkness. The dust storm shut down the airport in Kuwait and disrupted traffic across the Arabian Peninsula.
Intense northwest winds called shamal winds drove the fast-moving storm. They blow in from the northwest with the passing of a storm with a strong cold front, which is the leading edge of a mass of cold air. In this case, the cold front was over Iraq. It brought winds greater than 50 kilometers per hour (30 miles per hour) to Kuwait and slightly weaker winds to the rest of the region.
The winds picked up dust and sand from Iraq and Kuwait and blew it across the peninsula. The storm may have also picked up material over the Empty Quarter (Rub’ al Khali). An incredibly rich sand sea, the Empty Quarter contains about half as much sand as the Sahara Desert.
WeatherVortex.com/blog posts ©2010 McGuinnessPublishing All Rights Reserved World Wide
Also be sure to visit our other Unique World Websites:
Welcome To WeatherVortex™
The WeatherVortex blog, presents you with the latest, most unusual and bizarre clouds and weather imaginable. The Earth's atmosphere is a chaotic system, where small changes to one part of the system can grow to have large effects on the system as a whole. This process can product unbelievable, and at times, dangerous results. Also, be sure you visit our main website WeatherVortex.com
WeatherVortex Posts
-
22° Halo
by Tim McGuinness, Ph.D., Publisher with No Comments
The optical phenomenon a "22 degrees halo" because of its circular formation of 22 degrees around the sun.
A 22° halo is a halo, a type of opt... -
Ice Cap Pileus
by Tim McGuinness, Ph.D., Publisher with 1 Comment
A pileus (pronounced /ˈpaɪl.i‿əs/, Latin for cap), also called scarf cloud or cap cloud, is a small, horizontal cloud that can appear above... -
Warm Front Cold Front
by Tim McGuinness, Ph.D., Publisher with No Comments
Weather fronts are as familiar as rain. For those who live outside of Earth’s tropics, the movement of warm and cold masses of air creates the w... -
Polar Mesospheric Clouds
by Tim McGuinness, Ph.D., Publisher with No Comments
Noctilucent Clouds
After the Sun sets on a summer evening and the sky fades to black, you may be lucky enough to see thin, wavy clouds illumina... -
Lightning Over Brazil
by Tim McGuinness, Ph.D., Publisher with No Comments
The European Space Agency's Paolo Nespoli took this image of lightning over Brazil as seen from the International Space Station in January 2011. N... -
Ozone Hole Then And Now
by Tim McGuinness, Ph.D., Publisher with No Comments
Ozone is Earth's natural sunscreen, shielding life from excessive amounts of ultraviolet radiation. But Earth's ozone layer has been damaged... -
Cloud vortices off Isla Socorro
by Tim McGuinness, Ph.D., Publisher with No Comments
The cloud cover of the North Pacific Ocean was decorated with lacy swirls and bold stripes on May 11, 2011, when the Moderate Resolution Imaging S... -
Scirocco
by Tim McGuinness, Ph.D., Publisher with No Comments
A dense wall of dust barreled across the Arabian Peninsula on March 26-27, 2011. The massive storm stretches more than 500 kilometers (300 miles) ... -
Sun Halo
by Tim McGuinness, Ph.D., Publisher with No Comments
-
Prismatic Cirrus
by Tim McGuinness, Ph.D., Publisher with No Comments
-
Altocumulus Stratiformis
by Tim McGuinness, Ph.D., Publisher with No Comments
-
Gravity Waves
by Tim McGuinness, Ph.D., Publisher with No Comments
-
Horseshoes Anyone?
by Tim McGuinness, Ph.D., Publisher with 1 Comment
-
Eyeball Vortex
by Tim McGuinness, Ph.D., Publisher with No Comments
-
Anvil Rays
by Tim McGuinness, Ph.D., Publisher with No Comments
