Introduction to Meteorology

Meteorology

• Meteorology is the scientific study of the atmosphere, focusing on weather processes and forecasting.
• It originates from the Greek word "meteoros," meaning "high in the air."
• Meteorologists study atmospheric phenomena, weather patterns, and their impacts.

Importance of Meteorology

• Weather Forecasting: Helps prepare for and mitigate severe weather (storms, droughts).
• Agriculture: Crucial for planting and harvesting crops.
• Public Safety: Monitors conditions to prevent disasters and save lives.
• Climate Studies: Provides insight into climate change and its impacts.

Historical Perspectives

• Ancient civilizations studied weather to predict seasonal changes.
• Instruments like barometers (17th century) advanced observation.
• Organizations like NWS and WMO improved global monitoring and data sharing.

Key Terms

• Weather: The state of the atmosphere at a specific time and place (temperature, humidity, precipitation, cloudiness, wind).
• Climate: Average weather conditions over a long period (typically 30 years).
• Atmosphere: Layer of gases surrounding Earth (mostly nitrogen and oxygen).

Atmosphere Composition

• Nitrogen (N2): ~78%
• Oxygen (O2): ~21%
• Argon (Ar): ~0.93%
• Carbon Dioxide (CO2): ~0.04%
• Trace Gases: Neon, helium, methane, krypton, hydrogen.

Atmosphere Structure

• Troposphere: Lowest layer (Earth's surface to ~8-15km). Contains most mass, water vapor, and weather. Temperature decreases with altitude.
• Stratosphere: Above troposphere (~15-50km). Contains ozone layer, absorbs UV radiation. Temperature increases with altitude.
• Mesosphere: Above stratosphere (~50-85km). Meteors burn up. Temperature decreases with altitude.
• Thermosphere: Above mesosphere (~85-600km). Ionized gases, auroras. Temperature increases significantly with altitude.
• Exosphere: Outermost layer (~600-10,000km). Atmospheric particles sparse, escape into space. Temperature varies significantly and is influenced by solar radiation.

Pressure and Temperature

• Pressure decreases with altitude in all atmospheric layers.
• Temperature generally decreases with altitude in the troposphere and mesosphere but increases in the stratosphere and thermosphere. Ozone absorption heats the stratosphere.

Definitions and Differences

• Weather: Short-term atmospheric conditions (minutes to weeks).
• Climate: Long-term average weather over a significant period (decades to centuries).

Solar Energy

• Solar radiation: Energy from the sun (visible, UV, infrared).
• Distribution: Uneven based on Earth's curvature and tilt (equator warmer than poles).
• Importance: Drives weather patterns, influences climate, and supports life.

Convection, Conduction, and Radiation

• Convection: Heat transfer by fluid movement (warm air rises, cool air sinks). Responsible for many weather phenomena.
• Conduction: Heat transfer through direct contact.
• Radiation: Heat transfer through electromagnetic waves. The greenhouse effect is a form of radiation.

Ocean Currents

• Winds drive surface currents.
• Earth's rotation (Coriolis effect) deflects currents.
• Gyres are large-scale circular current systems.

Cyclones & Anticyclones

• Cyclones: Large-scale air masses rotating around a low-pressure center. Associated with clouds, rain, and wind.
• Anticyclones: Large-scale air masses rotating around a high-pressure center. Associated with calm, clear weather.

Weather Systems (Cyclones & Anticyclones)

• Real-world examples include Typhoons Haiyan (2013) and Katrina (2005), plus examples that are less frequent like the Siberian High.
• Discussion questions are provided for student-directed follow up learning.

Thunderstorms

• Thunderstorms: Storms featuring lightning and thunder, often accompanied by gusty winds.
• Classification: Air-mass and severe thunderstorms.
• Formation: Uneven heating, lifting (fronts, mountains).

Lightning and Thunder

• Rapid electrostatic discharge.
• Sound created by the rapidly expanding air around the discharge.

Tornadoes

• Highly destructive local storms with violent winds.
• Form rotating columns of air extending to the ground.
• Associated with severe thunderstorms (supercells).
• Formation: Mesocyclones, vertical wind shear.
• Intensity Scale: Enhanced Fujita Intensity Scale (EF-scale).

Hurricanes

• Intense low-pressure centers over tropical/subtropical oceans.
• Strong cyclonic circulation. Wind speeds >119 km/h.
• Structure: Eye, eye wall, spiral bands.
• Formation: Warm, moist air, latent heat release.
• Decay: Moving over cool water, land, or unfavorable conditions.
• Destruction: Storm surge, winds, heavy rain, inland flooding.
• Impact on the Philippines: Discusses various relevant typhoons.

Precipitation

• Rain: Liquid water, forms through collision-coalescence, in warm clouds.
• Snow: Ice crystals, forms through ice crystal process, in cold clouds.
• Sleet: Ice pellets, forms through partial melting and refreezing.
• Hail: Balls of ice, forms through repeated lifting and freezing in strong thunderstorms.

Important tools for measuring precipitation

• Rain gauges: Standard, tipping bucket, weighing, float recording, optical.
• Radar: Locates, calculates motion, and determines precipitation type.
• Satellites: Detect and monitor storms. Data useful prior to development of clouds and cyclonic flows.
• Aircraft: Provides detailed measurements near the storm.
• Data buoys: Continuous surface conditions over oceans.

Prediction challenges

• Timely warnings are essential to save lives and protect property.
• Balancing the need to warn with avoiding excessive or false warnings.
• Tracking small, short-lived storms is difficult.
• Storms can rapidly change their intensity, track, and even their occurrence.