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.


Novaya Zemlya Mirage Observed from Sicily, Italy

August 18, 2021


Composita novayla zimlya L

Photographer: Marcella Pace

Summary Author: Marcella Pace

Compared to the time given in almanacs, actual sunrises occur slightly
earlier and sunsets a bit later. This is because almanacs don't
account for atmospheric refraction. The light from the Sun and the
Moon, and indeed all celestial objects, passes through multiple layers
of our atmosphere before reaching our eyes. Layers of different
density, pressure and temperature can alter sunrises/sunsets by more
than two minutes. The altitude and latitude of the observer also affect
sunrise and sunset times.

The above image sequence, taken from Sicily, Italy on May 7, 2021,
results from strong atmospheric refraction. This is the Novaya
Zemlya mirage, which takes its name from an archipelago in the Arctic
Ocean. In 1597, the crew of Willem Barents' Dutch ship
witnessed this phenomenon when their ship was entangled in the ice. It
was necessary to spend the winter months in place and wait for the
return of the Sun, predicted for February 8. In reality, however,
because of a pronounced thermal inversion they were able to see the Sun
on January 24, 15-days earlier than expected. Note that as shown above,
the Sun as photographed in the last image had already set by about 3
minutes but was still visible. Click here to see a video of the
complete sequence.

Photo and other details: Nikon D7100 camera; Sigma 600 mm lens.
Altitude of 178 m above sea level; temperature of 18.5 C °; humidity of
84%; pressure of 1.014 mb.
* Gatto Corvino, Marina di Ragusa, Sicily, Italy Coordinates:
36.81311,14.57088

Related EPODs

Novaya Zemlya Mirage Observed from Sicily, Italy Cumulonimbus
Cloud, Rainbow and Central Bohemian Uplands Smoke from Wildfires
and the Planet Mars Archive - Ridge Line Induced Crepuscular Rays
Circumhorizon Arc over Viterbo, Italy Noctilucent Clouds Above
Paris on a Summer’s Eve
More...

Atmospheric Effects Links

* Atmospheric Optics
* 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 14 weeks, 5 days, 12 hours, 15 minutes
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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.


Archive - Earth's Shadow in Red Light

September 18, 2021

6a0105371bb32c970b019b00f50755970b

Every weekend we present a notable item from our archives.

This EPOD was originally published November 30, 2013.

Photographer: Luis Argerich
Summary Authors: Luis Argerich; Jim Foster

6a01116860210d970c019b00fbd174970c-320wi The photo above shows a
view near Tornquist, Argentina, using a filter sensitive to the 720
nm region (red light) of the electromagnetic spectrum. This is
the far-end of the visible spectrum -- wavelengths are longer here
than in the green or blue portions of the spectrum. The camera is
looking toward the eastern horizon just after sunset. Note the
blue-fringed strip of sky between the two hill slopes at center. This
is known as the Belt of Venus. Our eyes, which utilize the entire
visible spectrum (from about 375-750 nm), sees this band in pinkish
hues. The dark wedge below the Belt of Venus is the edge of night --
the rising Earth's shadow. Healthy vegetation appears white here
since chlorophyll is reflective in red light. The photo at left
shows that, even in winter, the Argentinian plains are always green. It
was taken on July 5, 2013, the same day and at the same location as the
above photo.

Photo details - Inset: Camera Model: Canon EOS 6D; Aperture: f/0.0;
Exposure Time: 0.017 s (1/60); ISO equiv: 1600.
* Tornquist, Argentina Coordinates: -38.071660,-62.008162

Related EPODs

Archive - Earth's Shadow in Red Light Wildfire Smoke Plume Over
Eastern Idaho The Rio Grande Estuary Spirit Lake in the Shadow
of Mount St. Helens Journey to the Center of the World Archive
- Washington, D.C. from Space
More...

Geography Links

* Atlapedia Online
* CountryReports
* GPS Visualizer
* Holt Rinehart Winston World Atlas
* Mapping Our World
* Perry-Castañeda Library Map Collection
* Types of Land
* World Mapper

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

https://epod.usra.edu

--- up 2 weeks, 1 day, 21 hours, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)

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.


Lower Yellowstone Falls

October 18, 2021

Yellowstone Falls

Photographer: Stephanie Becker

Summary Author: Stephanie Becker

The picture above features a breathtaking waterfall within an area of
Yellowstone National Park named the Grand Canyon of
Yellowstone. This was the first time I visited Yellowstone National
Park and I was in awe of its beauty. The 308 ft (93 m) tall Lower
Falls shown above are a part of the Yellowstone River. I inquired
as to why there was a patch of green at the top of the falls and
learned that there is a “crack” in the edge of the rock where the water
falls over the edge. The green coloring is where the water is deeper
than the rest of the falls so it takes longer for it to aerate and turn
white like the surrounding water.
* Lower Yellowstone Falls, Wyoming Coordinates: 44.717956,
-110.496022

Related EPODs

Lower Yellowstone Falls Archive - Pamukkale, Turkey Storm,
Stars and Mt Etna Thunderstorm at Sunrise in Canyonlands National
Park Archive - Earth's Shadow in Red Light Wildfire Smoke Plume
Over Eastern Idaho
More...

Geography Links

* Atlapedia Online
* CountryReports
* GPS Visualizer
* Holt Rinehart Winston World Atlas
* Mapping Our World
* Perry-Castañeda Library Map Collection
* Types of Land
* World Mapper

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

https://epod.usra.edu

--- up 6 weeks, 3 days, 21 hours, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)

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.


Knik Arm Tides of Alaska

November 18, 2021

High-low-tide_epod

Photographer: Gabrielle Tepp

Summary Author: Gabrielle Tepp

Oceans are well known to have twice daily tides, but not all
tides are equal. Among many factors, the shape of bays,
topology of the sea floor, and phase of the moon all affect the
size of tides. Cook Inlet, particularly Turnagain Arm, has the
third largest tidal range in North America and the largest in the
United States. These photos show the difference in tides in the
Knik Arm of Cook Inlet, along the coast of Anchorage, Alaska, where
the average tidal range is about 26 ft (8 m). The top photo was taken
on August 21, 2021 near the peak time of a 30 ft (9.2 m) high tide. In
contrast, the bottom photo was taken three days later near a low tide
of -1.5 ft (-0.5 m). The difference is quite dramatic! While hard to
tell from the photos, the gully is deep enough for a person to fit
in. Fish Creek is located to the right of the imaged area and typically
flows into the gully with a small waterfall. The highest tides,
however, fill the gully to the same level as the creek. When the tide
is low, mudflats made of glacial silt are revealed. Shorebirds
like to feed in the small pools of water that form on the mud. Be
careful if you decide to wander out though – it’s easy to get stuck in
the mud and you don’t want to be stranded out there when the tide comes
in!
* Anchorage, Alaska Coordinates: 61.437, -149.770

Related EPODs

Knik Arm Tides of Alaska The Law of the (Colorado) River
Utah’s Great Salt Lake Archive - Orange Mound Spring Soap
Lake, Washington Archive - Iguazu Falls
More...

Hydrology Links

* Current Sea Surface Temperature
* NOAA Ocean Explorer Gallery
* Ocean Color
* What is hydrology?
* Tides and Currents
* Water Resources of the United States
* World Waterfall Database
* The USGS Water Science School
* World Water Database
* The World’s Water
* USGS Surface Water Information Pages

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

https://epod.usra.edu

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