"Clouds_Lecture"

Page 1: Introduction to Clouds

  • Quote: Joni Mitchell, 1967 - Explores perceptions of clouds.

  • Definition of Hydrometeor: A visible aggregate of minute water droplets and/or ice particles above earth’s surface.

  • Cloud Classification Overview (1802):

    • Height: "Étage" - Cloud Base Elevation

    • Composition:

      • Ice Crystals

      • Water Droplets

      • Supercooled Water Droplets

      • Combinations

    • Description:

      • Patches, Masses, Layers

      • Shapes, Outlines, Elements

      • Features (Turrets, Filaments, Tuffs)

  • Historical Reference:

    • Luke Howard dubbed the "Father of Meteorology" (1772-1864).

    • Babylonians, around 650 B.C., predicted short-term weather patterns based on clouds and optical phenomena (e.g. haloes).

Page 2: Classification of Clouds

  • Cloud Families:

  • Based on the height of the cloud base:

    • Cirro (3rd Étage): High Level – 8 km to 18 km

    • Alto (2nd Étage): Middle Level – 2 km to 8 km

    • Strato (1st Étage): Low Level – 0 km to 2 km

    • Cumulo (Vertical Development):

  • Carl Linnaeus's Contribution (1707-1778):

    • "Systema Naturae" framework: Family - Genus - Species - Varieties.

  • Hugo Heldebrandson (1838-1925): Published International Cloud Atlas (1896).

Page 3: Cloud Families: High Level Clouds

  • Cirro Family (8 km - 18 km):

    • Characteristics:

      • Lumps (Cumuliform)

      • Layers (Stratiform)

    • Cloud Types:

      • High clouds exhibiting various forms:

        • Cirrus (Ci)

        • Cirrocumulus (Cc)

        • Cirrostratus (Cs)

Page 4: Cloud Families: Middle Level Clouds

  • Alto Family (2 km – 8 km):

    • Forms:

      • Lumps (Alto-cumulus)

      • Layers (Alto-stratus)

  • Height Classifications:

    • Alto Family layers at middle altitudes.

Page 5: Cloud Families: Low Level Clouds

  • Strato Family (0 km – 2 km):

    • Formations:

      • Layers (Stratus)

      • Clouds of Vertical Development (Cumulo)

  • Proverb Example:

    • “If in the sky you see cliffs and towers, it won’t be long before there is a shower.”

Page 6: Cloud Genera

  • Cloud Genera:

    • Classification based on composition and description (Homogeneous/Heterogeneous).

    • Types:

      • Ice Crystals

      • Supercooled Water Droplets

      • Water Droplets

    • Descriptions:

      • General shapes: lumps (Cumuliform) or layers (Stratiform).

    • Total Genera: 10.

Page 7: High Clouds Genera

  • Cirrus (Ci):

    • Description: Thin, transparent filaments at high altitude (8 km - 18 km).

  • Cirrocumulus (Cc):

    • Known as "Mackerel sky"

    • Weather Prediction: "3 days dry."

  • Cirrostratus (Cs):

    • A fibrous veil cloud with high transparency.

Page 8: Middle Clouds Genera

  • Alto Family Genera:

  • Types:

    • Altocumulus (Ac):

      • Known as "Bellow Clouds" or "Benard Cells."

      • Formed by Supercooled Water Droplets and Water Droplets.

    • Altostratus (As):

      • Sometimes a rain cloud; known for its fibrous or striated appearance.

Page 9: More on Middle Clouds

  • Altostratus:

    • Sunset observations, fibrous sheets of heterogeneous cloud types.

  • Strato Family:

    • Stratocumulus (Sc): Rounded masses or rolls below 2 km.

  • Stratus (St):

    • Low layer with distinct base, may contain suspended raindrops.

Page 10: Continued Low Level Clouds Genera

  • Nimbostratus (Ns):

    • Thick, dark grey layer; indicative of rain.

  • Stratus Nebulosus (St neb):

    • Diffuse cloud base with no distinct features.

Page 11: Vertically Developmental Clouds

  • Cumulus (Cu):

    • Clouds with vertical growth, often associated with fair weather.

  • Cumulonimbus (Cb):

    • Thunderstorm clouds, dense and vertically extensive.

Page 12: Cloud Species

  • Cirro Family Species:

    • Cirrus fibrates (Ci fib): Filamentous textures

    • Cirrus uncinus (Ci unc): Hooked filaments; relates to weather predictions.

Page 13: Additional Cloud Species in Cirro Family

  • Cirrus spissatus (Ci spi): Thickening and developing cirrus.

  • Cirrus castellanus (Ci cas): Turreted formations of cirrus.

  • Cirrus floccus (Ci flo): Fluffy textures resembling tufts.

Page 14: Cirrocumulus Species

  • Cirrocumulus Stratiformis (Cc str):

    • Spread out cloudlets across the sky.

  • Cirrocumulus Lenticularis (Cc len):

    • Lens-shaped formations.

  • Cirrocumulus Castellanus (Cc cas):

    • Displaying turret-like features.

Page 15: Cirrostratus Variants

  • Cirrostratus fibrates (Cs fib): Filamentous variant.

  • Cirrostratus nebulosus (Cs neb):

    • Known for creating rings around celestial bodies.

Page 16: Alto Family Species

  • Altocumulus stratiformis (Ac str):

    • Extensive cloud layer spreading out.

Page 17: Continued Alto Family Variants

  • Altocumulus castellanus (Ac cas):

    • Turreted lumps of cloud.

  • Altocumulus lenticularis (Ac len):

    • Lens shapes reminiscent of lenticular clouds.

Page 18: Rare Altocumulus Specie

  • Altocumulus volutus (Ac vol):

    • Recently identified very rare, long horizontal rolling cloud.

Page 19: Strato Family Species

  • Stratocumulus Family:

  • Species Examples:

    • Stratocumulus stratiformis (Sc str): Spread across the sky.

    • Stratocumulus lenticularis (Sc len): Lens formations.

Page 20: More on Strato Family

  • Stratocumulus volutus (Sc vol):

    • Roll Clouds generally detached.

  • Stratus Fractus (St fra):

    • "Broken sky cover" with ragged appearances.

Page 21: Nimbostratus Variant

  • Nimbostratus (Ns):

    • Characterized by dark thick grey colonies, typically indicates rainfall.

Page 22: Cumulus Family Species

  • Cumulus Variants:

    • Cumulus humilis (Cu hum): Fair weather cumulus.

    • Cumulus mediocris (Cu med): Moderate extent; small protuberances.

Page 23: Cumulonimbus Types

  • Cumulonimbus calvus (Cb cal):

    • Represents vertical striae.

  • Cumulonimbus capillatus (Cb cap):

    • Known for forming cirriform anvil shapes.

Page 24: Summary of Clouds

  • Building a Cloud:

    • Collect multiple genera and species in a single observation.

    • Photo Collection Examples:

      • Various combinations of observed cloud types.

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