Earth and Space Science 102 - Lecture 1 Notes

Course and Instructor Introduction

• Instructor: Stephanie Welch
• Department: Chemistry and Physics
• Course Prerequisites: None required, but Earth and Space Science 101 recommended

Course Structure

• Units Covered:
  1. Earth's Atmosphere and Meteorology
  2. Solar System
  3. Universe and Galaxies
• Logistics: Exam dates, syllabus, class structure on Moodle

Meteorology Overview

• Focus of Lecture: Basics of meteorology, weather, and climate
• Key Concepts: Temperature, humidity, clouds, precipitation, wind, and air pressure

Elements of Weather and Climate

Air Pressure

• Definition: Force exerted by the weight of air on the Earth's surface
• Standard Sea Level Pressure: 1013.25 millibars
• Factors Affecting Air Pressure:
  • Temperature: Controls how fast particles move
  • Humidity: Affects air's weight
• Relationship: Air moves from high to low pressure

Temperature

• Explanation: Average kinetic energy of molecules
• Effect on Air Pressure:
  • Cold air: Particles move slower and are denser, leading to higher pressure
  • Warm air: Particles move faster and are less dense, leading to lower pressure
• Heat Transfer:
  • Conduction: Poor in air
  • Convection: Important for atmospheric movement
  • Radiation: Transfer via wavelengths

Humidity

• Definition: Amount of water vapor in the air
• Impact on Air Pressure: More water vapor means lower air pressure
• Absolute vs Relative Humidity:
  • Absolute: Actual amount of water vapor
  • Relative: Percentage based on air's capacity to hold vapor

Atmospheric Layer Structure

• Layers of the Atmosphere:
  • Troposphere: Weather sphere, up to 7 miles, temperature decreases
  • Stratosphere: Contains ozone layer, temperature increases
  • Mesosphere: Coldest layer, temperature decreases
  • Thermosphere: Temperature increases, transitions to space
• Importance of Temperature Changes: Defines atmospheric layers

Closing Remarks

• Next Lecture: Global circulation of Earth's atmosphere
• Reminder: All concepts discussed are key to understanding atmospheric dynamics

Note

• Air pressure is a crucial factor in weather phenomena; high pressure leads to clear conditions, low pressure to storms.
• Understanding the structure and composition of the atmosphere is vital for meteorology.