EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Fallstreak Hole and Circumzenithal Arc over Hong Kong

March 22, 2022

1F276D7A-5F4E-4C55-9CA8-1A422AAF30EC

Photographer: Li Yuen Han

Summary Authors: Li Yuen Han; Cadan Cummings

The photo above features both a fallstreak hole and
circumzenithal arc observed from Jordon, Hong Kong. Fallstreak
holes, also referred to as hole punch clouds, are created when a cloud
layer composed of supercooled water droplets is unsettled and
produces ice crystals. This phenomenon is often caused in cirrocumulus
or altocumulus clouds by jet aircraft that pass through a cloud deck
producing turbulent air behind their wings and engines. As the ice
crystals nucleate, the surrounding water evaporates and ice
crystals slowly fall to the ground to form this unique circular hole in
the cloud. Looking at the center of the cloud hole, one can also see a
faint circumzenithal arc. These two phenomena are likely correlated
because as the ice crystals accumulate in the air, they act like a
prism and refract incoming light to produce what looks like an
upside-down rainbow. Photo taken December 9, 2021.
* Jordan, Hong Kong Coordinates: 22.3049, 114.1692

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Cloud Links

* Atmospheric Optics
* The Cloud Appreciation Society
* Cloud Atlas
* Color and Light in Nature

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 3 weeks, 1 day, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)

EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


Dust Devils on a Dry Lakebed

November 22, 2022


Dust-devils
Photographer: Dale Chadwick
Summary Author: Dale Chadwick
The photo above shows dust devils on a dry lakebed southwest of
Winnemucca, Nevada, as observed in the early afternoon of July 4, 2022.
I was about 2 to 3 miles (3-5 km) away from when I noticed dust and
sand swirling in the air. The largest of these devils appears to be
over 100 feet (30 m) high and perhaps 30 feet (9 m) in width. I was
surprised at how long they persisted -- visible for at least 10
minutes.

Dust devils occur when the surface becomes sufficiently heated to
form a weak updraft in the lower atmosphere, just above the ground.
Once formed, the little rotating column of air may twist
counterclockwise or clockwise and is typically barely strong enough to
lift grains of sand.

Photo details: Two views taken with a 300MM zoom lens.

Winnemucca, Nevada Coordinates:


Related EPODs

Dust Devils on a Dry Lakebed Moondog and Etna Lava Flow Two
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Atmospheric Effects Links

* Atmospheric Optics
* Optic Picture of Day: Gruppo Astrofili Galileo Galilei
* Color and Light in Nature
* The Colors of Twillight and Sunset
* Refraction Index
* Image Gallery: Atmospheric Effects
* What is a Rainbow?

-
Earth Science Picture of the Day is a service of the Universities
Space Research Association.

https://epod.usra.edu

--- up 38 weeks, 1 day, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)