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.


Different Ice Patterns Inside a Hailstone

January 19, 2023

Mario-Freitas-Nov23-2022

Photographer: Mario Freitas

Summary Author: Mario Freitas

The photo above was taken just after a violent spring storm in
Curitiba, Brazil. The collected 1-inch diameter (2.54 cm)
hailstone fragment shows a milky nucleus surrounded by alternating
rings of transparent and translucent ice.

Hail can be formed when thunderstorm drafts carry up raindrops into
higher freezing layers of the atmosphere. A hailstone grows inside
a cloud each time it collides with water drops making them freeze onto
its surface, until an upper limit is reached when the updraft can no
longer support its weight, causing it to fall and impacting the
ground. Microphysical processes determine density, structure, and
sizes of hailstones. At very high altitudes, temperature can be so
low that few liquid water drops remain, so hailstones don’t reach
significative sizes.

The structure of a cloudy ice layer scatters light in all
directions because specific temperature conditions cause
supercooled liquid water to freeze instantaneously on hailstone
surfaces, resulting in cracked ice with trapped air bubbles ( dry
growth). Light is otherwise refracted leading to the hailstones'
transparency if the water freezes slowly enough, permitting penetration
into the gaps before freezing and thus allowing air bubbles to escape
( wet growth). Photo taken on November 23, 2022.


Curitiba, Brazil Coordinates: -25.4372, -49.2700


Related EPODs

Different Ice Patterns Inside a Hailstone Summer Storm on the
Mediterranean Lightning and the Eiffel Tower Rainshaft Spotted
in New York Waterspout Over Lake Los Molinos Dust Cloud Near
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More...

Severe Weather Links

* World Severe Weather Information Center
* Enhanced Fujita Scale
* A Lightning Primer
* More About Thunderstorms
* Staying Safe Outdoors in Severe Weather
* NOAA Storm Prediction Center
* Patterns of Lightning Activity
* US National Weather Service

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

https://epod.usra.edu

--- up 46 weeks, 3 days, 20 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.


Brocken Spectre and Glory Observed from Viterbo Airport, Italy

February 17, 2023

Gloria-e-Spettro

Fogbow-Gloria-Spettro

Photographer: Marco Meniero

Summary Author: Marco Meniero

Suppose we're standing on a hill and the Sun is shining behind us, our
shadow is projected onto the fog below and is apparently transformed
into a pyramid-shaped silhouette with its apex at the antisolar
point, right where the shadow of our head appears. This shadow is
called the Brocken Spectre (top photo) and was coined years ago
during observations held on the Hartz Mountains in Germany. If the apex
of the shadow is surrounded by a luminous halo then this is referred to
as a Glory (bottom photo), which can often be seen from the window
seat on a commercial jet. The Glory, like the Brocken Specter is an
antisolar phenomenon, and both result from the diffraction of
sunlight.

According to atmospheric physicist Robert Greenler, the halos drawn on
the heads of the saints in art history seem to be an
interpretation/reproduction of the Glory. Based on a theory formulated
by Van De Hulst H. C, the rings of the Glory are formed by water
droplets or minute ice crystals found in stratus-type clouds. The
radius of the concentric rings can vary from a minimum of 1.2° to a
maximum of 8.3°. Photos taken on December 28, 2022.

Photo details: Nikon Z9 camera; ISO 32; optic Nikon S14-12/2.8 lens;
f/4.5).


Viterbo Airport, Italy Coordinates: 42.436111, 12.061667


Related EPODs

Brocken Spectre and Glory Observed from Viterbo Airport, Italy
Anti-twilight Colors and Belt of Venus Splendid Sundog over
Montreal, Canada The Fisherman and the Full Omega Moon Inferior
Mirage off the Coast of Sicily Crepuscular Rays Observed from
Italian Alps
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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 50 weeks, 6 days, 21 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)