Meteorology Study Notes

Key Meteorological Concepts

  • Terms:

    • Advection: Horizontal movement of air.

    • Convergence: Air parcels moving closer to each other.

    • Divergence: Air parcels moving away from each other.

    • Convection: Upward motion associated with low pressure.

    • Subsidence: Downward motion associated with high pressure.

Global Circulation

  • Formation: Insolation causes unequal heating, creating three circulation cells:

    • Tropical cell (Hadley Cell) around the equator.

    • Mid Latitude (Ferrell) cell between tropics and poles.

    • Polar cell at the poles.

  • Pressure Patterns:

    • Equatorial Trough (low pressure), Subtropical Ridge (high pressure), Polar Highs and Subpolar Lows.

Jet Streams

  • Fast-flowing air currents at the Tropopause, generally easterly.

  • Types: Polar Jet (between polar and mid-latitude cells), Subtropical Jet (between mid-latitude and tropical cells).

Turbulence Types

  • Convective Turbulence: Caused by thermal currents.

  • Mechanical Turbulence: Due to physical obstructions.

  • Clear Air Turbulence: Associated with jet streams and high altitudes.

Icing Conditions

  • Types of Icing:

    • Rime Ice: Formed by small supercooled droplets freezing on contact.

    • Clear Ice: Formed by large supercooled droplets spreading upon contact.

    • Conditions: Icing can occur at varied temperatures and in visible moisture.

Coriolis Force

  • Caused by Earth's rotation, deflecting moving air: right in the northern hemisphere, left in the southern hemisphere.

  • Affects wind patterns and creates circular movements in the atmosphere.

Stability and Instability

  • Stable Air: Cooler than surroundings, tends to sink.

  • Unstable Air: Warmer than surroundings, tends to rise.

  • Conditional Instability: Depends on moisture and temperature structure.

Cloud Types and Weather Effects

  • Cumulonimbus (Cb): Associated with thunderstorms, heavy precipitation, and turbulence.

  • Stratus/Nimbostratus (Ns): Causes continuous rain, low visibility.

  • Cumulus (Cu): Generally fair weather, can indicate turbulence.

Precipitation Processes

  • Forms: Rain, snow, sleet, freezing rain.

  • Growth Processes: Coalescence and Bergeron processes in warmer and colder clouds, respectively.

Atmospheric Composition

  • Major Gases: 78% Nitrogen, 21% Oxygen, trace amounts of Argon and greenhouse gases like CO2.

  • Impacts: Greenhouse gases affect heat retention and climate.

Temperature Measurement and Variation

  • Instruments: Thermometers (Liquid in glass, thermocouples).

  • Conversion: Celsius to Fahrenheit and vice versa.

Heat Transfer Mechanisms

  • Conduction: Transfer through direct contact.

  • Convection: Movement of air carrying heat energy.

  • Radiation: Transfer through electromagnetic waves (solar radiation).