• ES Picture of the Day 28 2021

    From Black Panther@21:1/186 to All on Thu Jan 28 11:00:44 2021
    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.


    Angle of Repose for Graupel

    January 28, 2021

    Image

    Graupel4a

    Photographer: Roger Hopkins
    Summary Author: Roger Hopkins

    The Nor’easter that visited the northeast U.S. on December 16-17,
    2020, brought 13 inches (33 cm) of fine-grained graupel to Lansing,
    New York, and an amazing 40 plus inches (100 cm) of snow and
    graupel to Binghamton, about 40-miles (64 km) to the southeast. The
    above photos show the angle of repose of these small uniform
    graupel pellets as they accumulated on horizontal surfaces. Graupel
    pellets bounce on impact and roll like tiny BBs off the edges of the
    pile. After a few hours, the pellets within the pile can weld together
    and as the height of the pile increases, fewer will land on the top,
    creating a pointed witches hat shape. My measurements show an angle
    of approximately 65 degrees. Note that the Avalanche Handbook and
    other sources show values that range from 35 degrees to as high as 80
    degrees.

    The top photo (at left, courtesy of Scott Geiger of Binghamton) shows
    his car with piled-up graupel that was still growing when the storm
    abated, while the fence posts (at top right in Lansing) could only
    sustain 3 inches (8 cm) high caps. The bottom photo illustrates the
    interesting effect on a round rotating surface; two soda bottles
    forming my squirrel barrier that will henceforth be called my snow
    accumulation rotisserie.
    * Lansing, New York Coordinates: 42.4842, -76.4799

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    Cryosphere Links

    * Guide to Frost
    * What is the Cryosphere?
    * Bentley Snow Crystals
    * Glaciers of the World
    * Ice, Snow, and Glaciers: The Water Cycle
    * The National Snow and Ice Data Center Google Earth Images
    * Snow and Ice Crystals

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

    https://epod.usra.edu

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  • From Black Panther@21:1/186 to All on Wed Apr 28 11:00:36 2021
    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.


    Sunrise and Cloud Mirages Observed from Monte Tomba, Italy

    April 28, 2021

    2021_01_30 - Sunrise

    Venturin - Sunrise 2

    Photographer: Giacomo Venturin
    Summary Authors: Giacomo Venturin; Jim Foster

    Mock mirages at sunrise or sunset are quite common (top photo),
    but one morning several weeks ago, while observing from Monte
    Tomba, Cavaso del Tomba, Italy, I also saw cloud mirages (bottom
    photo). This was a first for me. Initially, I didn't understand why the
    clouds near the horizon looked so strange -- I thought my eyes were
    focusing properly. Then I realized that the clouds were miraged as
    well. When mirages are seen, temperature variations near the
    surface must be sufficiently strong to enable light rays to bounce up
    and down before reaching the observer’s eyes. Photos taken on February
    16, 2021.
    Photo Details: Canon 70/200 + 2x camera; Canon 60D lens; 400 mm; f/11;
    100 ISO, 1/30 second exposure.
    * Cavaso del Tomba, Italy Coordinates: 45.8700, 11.9032

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    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

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  • From Black Panther@21:1/186 to All on Fri May 28 11:00:26 2021
    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.


    Purple Anemone

    May 28, 2021


    Menashe_anemone_Picture3

    Photographer: Menashe Davidson
    Summary Author: Menashe Davidson

    The main characteristic of the purple anemone flower is its
    showiness. This is one flower you’ll always notice in the garden,
    regardless of whatever is in bloom nearby. It belongs to the genus
    anemone, comprised of over 200 species. The word “ anemone” is
    derived from the Greek term "anemos" meaning winds. Thus, the purple
    anemone is sometimes referred to as the windflower.

    Flowers of the purple anemone tend to retire once the Sun goes down, a
    phenomenon known as nyctinasty. On the montage pictured above, 4
    stages are demonstrated in the anemone’s diurnal cycle. All photos
    were taken in my home garden, in Rishon LeZion, Israel, on March 7,
    2021. When the flowers are open, in addition to their delicate petals,
    they expose their reproductive organs, illustrating a range of
    shapes, colors and curves (bottom left).


    Rishon LeZion, Israel Coordinates: 31.9730, 34,7925


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    Plant Links

    * Discover Life
    * Tree Encyclopedia
    * What are Phytoplankton?
    * Encyclopedia of Life - What is a Plant?
    * USDA Plants Database
    * University of Texas Native Plant Database
    * Plants in Motion
    * What Tree is It?

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

    https://epod.usra.edu

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  • From Black Panther@21:1/186 to All on Mon Jun 28 11:00:34 2021
    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.


    Lake Tahoe: Blue Gem of the Sierras

    June 28, 2021

    6a0105371bb32c970b026bded8df1a200c

    Tahoe120c_7june21

    Photographer: Ray Boren

    Summary Author: Ray Boren

    Straddling a state line shared by Nevada and California in the western
    United States, beautiful Lake Tahoe is set like a gargantuan blue
    gem in a high basin between the Sierra Nevada crest on the west
    and the Sierras’ Carson Range spur on the east. In the first
    photograph here, taken on June 7, 2021, the panoramic perspective to
    the south and southwest is from a high viewpoint above the north
    shore’s Incline Village, along Nevada’s Mount Rose Highway (State
    Route 431). A second photo, taken the same day, presents a shoreline
    view from Lake Tahoe’s north-shore resort town of Kings Beach,
    California.

    Tahoe’s name is an anglicization of a Native American Washoe tribal
    term describing “The Lake,” “Big Water,” or “Water in a High Place” —
    all quite apt. Tahoe is the largest fresh-water alpine lake in
    North America, covering 122,616 acres (49,621 hectares). With a depth
    of 1,645 feet (501 m), it is also the second-deepest in the United
    States (behind Oregon’s lovely Crater Lake). It is 22 miles (35 km)
    long, north to south, and 12 miles (19 km) at its widest, with 72 miles
    (116 km) of shoreline.

    Basin-and-range faulting is credited with forming a series of
    west-tilted blocks and east-dipping faults that produced the
    north/south trending basin about 2 million years ago. Elevations at
    Tahoe range from 6,225 feet (1897 m) at lake level to 10,891 feet (3320
    m) atop Freel Peak. The spectacular and pleasing natural beauty of
    today’s Lake Tahoe basin is the result of manifold geological processes
    over millions of years, the Geologic Survey notes, including marine
    deposition, granitic intrusion, tectonic uplift, volcanic eruptions,
    and ice-age glacial scouring and other forms of erosion.
    * Lake Tahoe Coordinates: 39.092, -120.033

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    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

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  • From Black Panther@21:1/186 to All on Wed Jul 28 11:00:38 2021
    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.


    Contrail Shadow Over Braunfels, Germany

    July 28, 2021

    2021-04-24 15.47.412

    Photographer: Oliver Stiehler

    Summary Author: Oliver Stiehler & Cadan Cummings

    2021-04-24 15.47.43 Sometimes being in the right place at the right
    time produces an unusual photo that reveals unique atmospheric
    phenomena. This photo shows an airplane contrail casting a shadow
    on wispy cirrus clouds in Braunfels, Germany. Contrails are
    formed when water from the airplane exhaust and the atmosphere
    condenses due to extremely cold temperatures and low
    atmospheric pressure. The result is line shaped clouds are produced
    which depending on wind speed and humidity can last for anywhere
    between seconds to several minutes.

    From this unique perspective, the contrail overhead is casting a shadow
    on a lower altitude cloud layer. Note that the shadow appears to be
    also ahead of the jet itself, which is explained by the Sun angle
    being directly overhead in addition to the condensation and ice
    crystals in the contrail scattering the incoming light making the
    shadow’s projection appear larger.

    Photo data: Huawei Mate 20 Pro with all automatic adjustment at 3x zoom
    factor
    * Braunfels, Germany Coordinates: 50.5169, 8.3909

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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

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  • From Black Panther@21:1/186 to All on Sat Aug 28 11:00:24 2021
    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 - Erta Ale, Ethiopia

    August 28, 2021

    6a0105371bb32c970b01b7c768d93c970b
    Every weekend we present a notable item from our archives.
    This EPOD was originally published April 7, 2015.

    Photographer: Joel Santos
    Summary Author: Joel Santos April 2015 Viewer's Choice

    Erta Ale is a continuously active, basaltic shield
    volcano in the Afar Region of northeastern Ethiopia. Its
    caldera is notable for holding one of world's longest-existing
    lava lakes -- first reported in 1906. Volcanoes with lava lakes are
    quite rare. Only six are known worldwide. The nearly full Moon, on
    the rise this early January night, illuminates the low clouds, acting
    to balance the light of the sky with the strong orange light of the
    bursting lava. Photo taken on January 10, 2015.

    Photo details: Fisheye lens; 8-15 mm; 85 sec exposure; f/4; ISO 400.
    * Erta Ale, Ethiopia Coordinates: 13.599722, 40.659722

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    Geology Links

    * Earthquakes
    * Geologic Time
    * Geomagnetism
    * General Dictionary of Geology
    * Mineral and Locality Database
    * Mohs Scale of Mineral Hardness
    * This Dynamic Earth
    * USGS
    * USGS Ask a Geologist
    * USGS/NPS Geologic Glossary
    * USGS Volcano Hazards Program

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

    https://epod.usra.edu

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  • From Black Panther@21:1/186 to All on Sun Nov 28 11:00:28 2021
    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 - Water Drops and Inverted Images

    November 27, 2021

    6a0105371bb32c970b015438b70cf2970c-750wi

    Every weekend we present a notable item from our archives.

    This EPOD was originally published December 24, 2011.

    Photographer: Bertrand Kulik
    Summary Authors: Bertrand Kulik; Jim Foster
    Within these decorative water drops is the inverted image of
    the flowers in my garden and my house in Paris, France. A liquid drop
    acts as a simple lens, like a camera lens, so the refracted
    image is upside-down when viewed through the drop. Note that these
    drops have more or less spherical shapes because surface tension
    minimizes the surface area of a drop of water or even a falling
    raindrop. Photo taken in early September 2011.

    Photo Details: Canon EOS 7D camera; 100mm macro lens with macro rings.
    * Paris, France Coordinates: 48.856667, 2.350833

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  • From Black Panther@21:1/186 to All on Tue Dec 28 11:00:26 2021
    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.


    The Cataclysmic Birth of Montana’s Earthquake Lake

    December 28, 2021
    QuakeLk261c_5sep21

    Quakelake210c_5sep21

    Photographer: Ray Boren

    Summary Author: Ray Boren

    In a time when cinematic and fantasy apocalypses abound, it is sobering
    to visit memorials to real-life tragedies, such as the U.S. Forest
    Service’s Earthquake Lake Visitor Center in southern Montana’s
    Custer Gallatin National Forest. The visitor center, shown in the
    left photo, stands amongst a tremendous swath of rocky debris. Below
    the center is the Madison River and the dead-tree-studded
    Earthquake Lake. To the east of the visitor center is U.S. Highway
    287, shown in the right photo, which rounds the 5-mile-long
    (8-kilometer) Earthquake Lake. The lake got its name after forming six
    decades ago as a result of the cataclysmic Hebgen Lake earthquake
    and the subsequent Madison Canyon landslide.

    As described by the visitor center, the powerful earthquake — 7.5
    on the Richter scale — occurred just before midnight on the moonlit
    summer evening of August 17, 1959. About 250 people had gone to bed in
    the canyon in tents, campers and cars at formal and informal campsites,
    as well as others nearby in cabins and lodges. “In the morning,”
    survivor Joann Gartland is quoted as saying, “we looked across from
    where we were, and the mountain had just fallen down.” After a night of
    confusion, terror and resilience, that sunrise revealed the desolation
    and carnage.

    QuakeLk247c_5sep21 The simultaneous tremors from the Red Canyon
    and Hebgen faults sent cascades roaring down the Madison River. Soon
    after, a section of the southern heights dislodged causing the canyon
    and river to be choked with 80 million tons of boulders, rubble and
    shattered trees. Debris formed a natural dam that created
    Earthquake Lake. Unsuspecting people were sadly crushed, trapped or
    lost in the dark, amid churning water, fallen rubble and wrecked cars
    and campers. Many survivors found and helped others with their injuries
    as well as guided them in the night to higher ground to await rescue,
    including to a spot now called Refuge Point.

    Inside the visitor center, poignant displays tell the stories of many
    survivors, of which some were young children at the time. A side road
    and various trails lead to viewpoints, waysides and markers. One such
    path leads to the huge block called Memorial Boulder, shown to the
    right. Far from its original location high on the other side of the
    canyon, it bears a plaque with the names of 28 people killed by the
    Hebgen Lake earthquake and the Madison slide — 19 of whom were
    entombed.
    * Earthquake Lake, Montana Coordinates: 44.831178, -111.422882

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    Geology Links

    * Earthquakes
    * Geologic Time
    * Geomagnetism
    * General Dictionary of Geology
    * Mineral and Locality Database
    * Mohs Scale of Mineral Hardness
    * This Dynamic Earth
    * USGS
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    * USGS Volcano Hazards Program

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

    https://epod.usra.edu

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