• ES Picture of the Day 30 2022

    From Black Panther@21:1/186 to All on Wed Mar 30 12:00:54 2022
    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.


    Skypools on Surface Waves

    March 30, 2022

    IMG_8493

    Photographer: Patti Weeks

    Summary Author: Patti Weeks

    Shown above is an abstract image containing distorted sunlit
    reflections of the sky, clouds, and a fishing dock on a pond
    stirred up by the wind. The optical result is a mixture of wavy lines,
    swirls and a complex phenomenon called skypools. However, viewing
    the picture from a different perspective, it could be said the abstract
    photo looks like a landscape consisting of meandering rivers, oxbow
    lakes, ponds, sandbars, and cliffs.

    Skypools are seen as distorted swirls and pools on the surface of
    gently moving bodies of water. The wind creates vibrational
    surface waves that move the water up and down. From this motion,
    crests and troughs are formed in the constantly changing curvature of
    the water surface. We do not see straight line images, as normally seen
    in the spectral reflection of a mirror, but instead diffuse
    reflections are visible on the waves at various degrees of convex
    and concave angles in addition to overlapping lines of sight from
    point-to-point. The distorted images change from moment to moment,
    meaning if another viewer at a different vantage point took a photo at
    the exact same time as this photo, the image would be completely
    different. Watch this video to see the motion of the ever-changing
    skypools and distorted reflections. Skypools are generally seen when
    the angle of the viewer’s sight is greater than 15 degrees, which
    coincides with when most of the surface of the wave is visible. Only
    when the wind stops can the water return to a relative state of
    equilibrium. Photo taken on February 10, 2022.

    Photo details: Apple iPhone 11 Pro; 6 mm, f/2, 1/122 second exposure,
    ISO-32
    * River Park North, Greenville, North Carolina Coordinates: 35.627,
    -77.360

    Related EPODs

    Skypools on Surface Waves Great Salt Lake’s Mirabilite Mounds
    La Cascata di Fondo and Orion The Hunter Waterfall in the
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    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

    --- up 4 weeks, 2 days, 21 minutes
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)
  • From Black Panther@21:1/186 to All on Mon May 30 12:00:28 2022
    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.


    Ice Crystal Formation on Frozen Soap Bubble

    May 30, 2022


    PatriciaR_IMG_0475a dusted cr 40 percent (003)

    Photographer: Patricia Rasmussen

    Summary Authors: Patricia Rasmussen; Jim Foster

    There are several things of interest visible in this image of a frozen
    soap bubble, which is approximately 1 in (2.5 cm) in diameter. The
    soap bubble film is a sandwich made up of two soap layers with a water
    layer in between. Colors near the central portion of the bubble are
    likely due to diffraction processes -- light is interacting with the
    thin soap film. Light waves are diffracted or scattered by the
    varying thickness of the film in such a way that the waves interfere
    with each other, creating regions of enhanced color (constructive
    interference).

    Frost crystals form in the water layer part of the bubble film; the
    bubble itself is a hollow sphere. When photographing the crystals, the
    depth of field is very shallow. So, the photographer chooses the place
    where crystal growth is most active and the crystal pattern most
    beautiful. Thus, the focus is either on the front or back wall of the
    bubble. In this case, the back wall is prominent, while the growing
    crystals on the front wall give a cloudy/hazy illusion to the image.
    Note that as the bubble ages, the film becomes thinner, and the color
    fades just before the bubble pops.

    This photo was taken from my unheated garage on February 24, 2022. The
    bubble is blown using a straw onto a base of snow, artificially
    backlit, with some purple-tinted cracked ice for interest. "Bubblers"
    say this is a highly addictive photographic subject because of the
    seemingly infinite variables that cause the coloration and crystal
    growth. It is! Click here to see a video of the crystals forming
    between the inner and outer surfaces of the bubble. Notice in this
    video that initially the crystals are rapidly swirling around the
    bubble, likely from my breath as I blow through the straw.

    Photo details: Canon 90D camera; F11; 1/250; 100 mm focal length; ISO
    800. Post processing was general—levels, contrast, and a small crop.
    * Eagle River, Wisconsin Coordinates: 45.9172, -89.2443

    Related EPODs

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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

    --- up 13 weeks, 20 minutes
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)
  • From Black Panther@21:1/186 to All on Thu Jun 30 12:00:58 2022
    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.


    Roll and Lenticular Clouds Above Taiwan

    June 30, 2022

    DSC_7148(1)

    Photographer: Wei-Chun Lin

    Summary Authors: Wei-Chun Lin; Cadan Cummings

    The photo above shows both a roll cloud (at far left) and lenticular
    cloud (center of photo) as seen from a hilltop near Taipei, Taiwan. As
    soon as I spotted satellite images showing the possibility of these
    cloud structures, I rode my motorcycle to Yangmingshan National
    Park near Taipei.

    Roll clouds are a type of arcus cloud that form on the leading
    edge of a storm. Unlike other shelf clouds, roll clouds are
    separate from the thunderstorm base. This specific roll cloud was
    still far away from the coast at the time of the photo. Their name
    comes from their horizontal “rolling” motion.

    Conversely, lenticular clouds are not related with storms. Instead,
    these uniquely shaped clouds form when moist air cools and then
    condensates as it passes over mountains. When the stable is forced
    over the ridge, atmospheric waves are created that produce the
    cloud’s characteristic lens-shape appearance. Click here for a
    time-lapse video of the clouds.

    Photo details: Nikon D850, f/11, 1/500 second exposure, 24mm
    * Taipei, Taiwan Coordinates: 25.033, 121.565

    Related EPODs

    Roll and Lenticular Clouds Above Taiwan Moonlit Monte Viso
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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 17 weeks, 3 days, 21 minutes
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (21:1/186)
  • From Black Panther@21:1/186 to All on Sat Jul 30 12:01:20 2022
    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.


    Mature Snapdragon Flowers Remain Closed

    July 29, 2022

    Menashe_snapdragon1a

    Menashe_snapdragon2

    Photographer: Menashe Davidson

    Summary Author: M enashe Davidson

    The time of flower opening marks the onset of a period in which
    pollinators are attracted by the flower sweetness, leading a pollen
    removal and pollination. In many species the flowers are open
    permanently, whereby the opening period is terminated by a closure
    movement, or by petal withering or abscission. But there are few
    species, such as snapdragons, where mature flowers stay closed.

    Snapdragons (Antirrhinum majus, family Plantaginaceae) have a wide
    range of flower colors, and they’re easily grown in gardens. The
    snapdragon flowers are closed flowers (top photo) with two modified
    petals, described as lips, that essentially prevent honeybees from
    penetrating them. Note, however, that the flowers can be opened when
    they're pressed on their sides (bottom photo). Here we can see the
    inside of the flower, where there are four stamens with white
    filaments surrounding a pistil (green stalk). Bumblebees, which
    are much bigger than honeybees, are the main pollinators for
    snapdragons because they’re larger size permits them to open the closed
    flowers. Photos taken in March 2022, from my home garden in Rishon
    LeZion, Israel.


    Rishon LeZion, Israel Coordinates 31.9730, 34.7925


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    Earth Science Picture of the Day is a service of the Universities
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  • From Black Panther@21:1/186 to All on Tue Aug 30 12:00:52 2022
    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.


    Hollow Stems in Amaryllis belladonna

    August 30, 2022

    Menashe_Stems

    Menashe_Stems2

    Photographer: Menashe Davidson menashe.davidson@gmail.com

    Summary Author: Menashe Davidson menashe.davidson@gmail.com

    While in my home-garden (in Rishon LeZion, Israel), I observed the
    erect hollow leafless stems of Amaryllis belladonna plant, also
    known as the Amaryllis lily and the August lily. Carrying
    inflorescences they bear showy funnel-shaped flowers (1st photo). I
    questioned the purpose of why there are hollow stems in some plants.
    Stems of course provide a transport system, mechanical support, and
    a primary growth point for plant. They also improve the presentation of
    the plant’s sexual organs, thereby increasing the plant's chance of
    reproduction.

    The common misconception was to believe that the hollow stem is solely
    for nutrient or water transport. But when I cut the stem in various
    heights, I learned that the hollow stem holds water only in the bottom
    4 or 5 inches (12 cm) -- most of the stem contains air (2nd photo).

    Scientists In University of Guelph (Ontario) studied differences in
    plant stem type, and how effectively they regulate their temperature.
    They found that the stem lumen (hollow portion of the stem) allows the
    plant to maintain a distinct internal microclimate and in the present
    of sunlight, the temperature in the lumen was slightly above that of
    the ambient air. Increases in temperature encourages growth of sexual
    organs in plants, which in turn helps the flower to develop quickly,
    becoming more prominent to pollinators. And this effect is exactly what
    I observed in Amaryllis flowers. (Below)

    Menashe_Stems3


    Rishon LeZion, Israel Coordinates: 31.9730, 34.7925


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    Earth Science Picture of the Day is a service of the Universities
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