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  2. Noctilucent cloud - Wikipedia

    en.wikipedia.org/wiki/Noctilucent_cloud

    Noctilucent clouds (NLCs), or night shining clouds, [1] are tenuous cloud-like phenomena in the upper atmosphere of Earth. When viewed from space, they are called polar mesospheric clouds (PMCs) , detectable as a diffuse scattering layer of water ice crystals near the summer polar mesopause .

  3. Nimbostratus cloud - Wikipedia

    en.wikipedia.org/wiki/Nimbostratus_cloud

    A nimbostratus cloud is a multilevel, amorphous, nearly uniform, and often dark-grey cloud that usually produces continuous rain, snow, or sleet, but no lightning or thunder. [ 1 ] [ 2 ] [ 3 ] Although it is usually a low-based stratiform cloud, it actually forms most commonly in the middle level of the troposphere and then spreads vertically ...

  4. Crepuscular rays - Wikipedia

    en.wikipedia.org/wiki/Crepuscular_rays

    Crepuscular rays are noticeable when the contrast between light and dark is most obvious. Crepuscular comes from the Latin word crepusculum , meaning "twilight". [ 2 ] Crepuscular rays usually appear orange because the path through the atmosphere at dawn and dusk passes through up to 40 times as much air as rays from a high Sun at noon .

  5. Atmospheric optics - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_optics

    A cumulonimbus cloud emitting green is a sign that it is a severe thunderstorm, [21] capable of heavy rain, hail, strong winds and possible tornadoes. The exact cause of green thunderstorms is still unknown, but it could be due to the combination of reddened sunlight passing through very optically thick clouds.

  6. List of cloud types - Wikipedia

    en.wikipedia.org/wiki/List_of_cloud_types

    Clouds of the genus nimbostratus tend to bring constant precipitation and low visibility. This cloud type normally forms above 2 kilometres (6,600 ft) [10] from altostratus cloud but tends to thicken into the lower levels during the occurrence of precipitation. The top of a nimbostratus deck is usually in the middle level of the troposphere.

  7. Glossary of meteorology - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_meteorology

    Also actiniform. Describing a collection of low-lying, radially structured clouds with distinct shapes (resembling leaves or wheels in satellite imagery), and typically organized in extensive mesoscale fields over marine environments. They are closely related to and sometimes considered a variant of stratocumulus clouds. actinometer A scientific instrument used to measure the heating power of ...

  8. What is graupel? How it is different from sleet or hail? - AOL

    www.aol.com/weather/difference-between-freezing...

    Unlike hail or sleet, graupel is soft and can be crushed easily in your hand, and is sometimes called "soft hail." It is also usually smaller than hail, with a diameter of around 0.08-0.2 inches.

  9. Night sky - Wikipedia

    en.wikipedia.org/wiki/Night_sky

    Paranal Observatory nights. [3] The concept of noctcaelador tackles the aesthetic perception of the night sky. [4]Depending on local sky cloud cover, pollution, humidity, and light pollution levels, the stars visible to the unaided naked eye appear as hundreds, thousands or tens of thousands of white pinpoints of light in an otherwise near black sky together with some faint nebulae or clouds ...