"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• Historical Reference: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.