Posts Tagged ‘Clouds’

Weather Word Wednesday : Glory

January 19th, 2011 1 comment

Have you ever been out hiking and looked down on a waterfall, surprised to see a round, rainbow colored halo? Or perhaps you’ve looked off towards a bank of clouds, with the sun at your back, and seen the same colored halo? If so, you’ve seen what meteorologists call a Glory.

Essentially, a Glory is “one or more sequences of faintly colored rings of light that can be seen by an observer around his own shadow cast on a water cloud (a cloud consisting mainly of small, uniform sized water droplets). It can also be seen on fog and exceptionally on dew.”  The glory can only be seen when the observer is directly between the sun and cloud of refracting water droplets.

Solar Glory

Solar glory at hot springs

Glories are not completely understood. The colored rings of the glory are caused by two-ray interference between “short” and “long” path surface waves – which are generated by light rays entering the droplets at diametrically opposite points (both rays suffer one internal reflection). Glories are often seen in association with a Brocken spectre, the apparently enormously magnified shadow of an observer, cast (when the Sun is low) upon the upper surfaces of clouds that are below the mountain upon which he or she stands. The name derives from the Brocken, the tallest peak of the Harz mountain range in Germany. Because the peak is above the cloud level, and the area is frequently misty, the condition of a shadow cast onto a cloud layer is relatively favored. The appearance of giant shadows that seemed to move by themselves due to the movement of the cloud layer (this movement is another part of the definition of the Brocken Spectre), and which were surrounded by optical glory halos, may have contributed to the reputation the Harz mountains hold as a refuge for witches and evil spirits.

The next time you have your back to the sun and clouds at your front, or are up high with clouds below, try and find a Glory on your shadow. If you have a camera with you, and see a Glory, send us a snapshot!

Source : Wikipedia

View From The Top

July 30th, 2010 2 comments

I was flying to Seattle earlier this week, and snapped this picture from the plane. I love how clouds look from the top! Notice the vertical development punching it’s way through the deck!

View From The Top

View From The Top

Categories: Clouds, Weather Tags: ,

Picture Of The Week

April 19th, 2010 No comments

So, not the best picture in the world, but I was able to catch some growing mamatus clouds this morning on my way to work. I had to use my iPhone camera to take the pic. I love how these clouds look!

Mamatus Clouds in Tucson, AZ

Mamatus Clouds in Tucson, AZ

Cirrus Clouds

March 5th, 2010 No comments

A couple days ago, as a storm was moving out of the area, we got some classic cirrus clouds in the upper atmosphere. These types of clouds are very high in the atmosphere, are traditionally thin with wispy strands, and can often herald the arrival of a storm (in this case they were remnants of a previous storm). Cirrus clouds like to live at levels above 26,000 feet (8000 meters), and are formed when water vapor freezes into ice crystals. The lack of moisture at such high altitudes is one of the reasons these clouds tend to present so thin and wispy.

Cirrus Clouds in Tucson, AZ

Cirrus Clouds in Tucson, AZ

A lot of times in Tucson we see hair like filaments of ice crystals precipitating out of the clouds in the form of what’s called virga. These streaks often indicate the difference in the motion of air between the upper part of the cirrus cloud and the lower air below it. It appears as though rain is coming from the cloud, but it’s actually ice crystals, most of which evaporates before it hits the ground (especially in Arizona). On some days, cirrus cloud development is so extensive that they become virtually indistinguishable from one another, forming what’s called cirrostratus clouds.

Another type of cirrus cloud that you’re already very familiar with is the condensation trails, or contrails,  seen in the sky coming from planes. These trails are basically artificial clouds formed by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets. If the air is cold enough, this trail will comprise tiny ice crystals. On some days, with a high level of air traffic, you can see contrails crisscrossing the sky, and these contrails often hang around for some time. It’s pretty neat!

Clouds are very cool, and an obviously integral part of weather. I intend to eventually go through all the various cloud types, hopefully using images I’ve shot with my camera. If you understand why a particular cloud type is in the area, you have a good idea of what sort of weather might be on the way.