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Overview of Physical Geography Concepts

May 5, 2025

Physical Geography Lecture Notes

Exam Coverage

  • Test One:
    • Chapter 1: Introduction to Geography and Earth Systems Science
    • Chapter 2: Portraying Earth
    • Chapter 3: Earth Sun Relations

Fundamental Concepts in Geography

  • Geography: Study of spatial patterns of "Things"; involves holistic thinking.

    • Overlaps with various sciences.
  • Cartography: Art and science of making maps.

Five Themes of Geography

  1. Location:
    • Absolute (e.g., coordinates, addresses)
    • Relative (in relation to other locations)
  2. Place: What occurs at a location.
  3. Human Environment Interaction: Example: LA Basin and smog.
  4. Movement: Like migration, relocation, and changes due to movement.
  5. Region: Unique spatial patterns and scientific inquiries.

Physical Geography

  • Branch dealing with Earth's natural features and processes.
  • Referred to as Earth Science; encompasses:
    • Biosphere
    • Hydrosphere
    • Lithosphere
    • Atmosphere

Measuring the Earth

  • Latitude and Longitude: Used for absolute location.
    • Equator, prime meridian, hemispheres.
  • Earth's Shape: Oblate spheroid—equatorial diameter slightly larger.

Geographic Grid

  • Latitude (Y-axis):
    • Divides Earth into Northern and Southern Hemispheres.
    • Key lines include North Pole, Arctic Circle, Equator, Tropics, and Antarctic Circle.
  • Longitude (X-axis): Divides Earth into Eastern and Western Hemispheres.
    • Uses degrees, minutes, and seconds for precision.

Maps and Cartography

  • Maps convey specific information.
  • Types of Maps:
    • Topographic
    • Thematic
  • Projection Issues: Distortion in size, shape, area, distance, and direction (SSADD).
  • Map Scales: Ratio/fraction, graphical, and verbal scales.

Geographic Information Systems (GIS)

  • Integration of geography with computer science and remote sensing.

Earth and Sun Relationships

  • Sun: Center of the solar system; energy source for Earth.
    • Shortwave energy; distance to Earth ~93 million miles.
  • Earth's Orbit: Elliptical; concepts of perihelion and aphelion.
  • Seasons: Caused by Earth's axial tilt.
    • Key concept: Insolation and its distribution.
  • Factors Influencing Insolation:
    1. Sun's temperature
    2. Earth's distance from the sun
    3. Absorption and scattering
    4. Latitude

Earth's Rotation

  • West to East; 24-hour rotation, affecting day length and climate.
  • Coriolis Effect: Influences movement of winds and ocean currents.

Atmosphere

  • Essential for life, composed mainly of nitrogen and oxygen.
  • Chemical Layers:
    • Heterosphere: Above 80-85 km
    • Homosphere: Below 80 km
  • Temperature Layers:
    • Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere
  • Air Pressure: Decreases with altitude; measured by barometer.

Weather and Climate

  • Weather: Short-term atmospheric conditions.
  • Climate: Long-term averages of weather over time and space.
  • Climate Controls:
    1. Latitude
    2. Land and water distribution
    3. Atmospheric and oceanic circulation
    4. Topography
    5. Altitude
    6. Earth's rotation
    7. Storms
  • Energy and Heat: Concepts of insulation, conduction, convection, radiation.

Greenhouse Effect

  • Vital for life; enhances by human activity.
  • Greenhouse Gases: CO2, water vapor, methane.
  • Heat Transfer Laws:
    • Conservation of energy; transfer from high to low concentrations.

Atmospheric Dynamics

  • Cyclones (Low Pressure) and Anticyclones (High Pressure): Influence weather patterns.
  • Wind Patterns: Affected by pressure gradients, Coriolis effect, and friction.

Atmospheric Moisture

  • Humidity: Energy from condensation; states of water transformation.
  • Cloud Formation: Saturation, dew point, and relative humidity.

Precipitation

  • 5 C's of Rain:
    1. Evaporation
    2. Cooling
    3. Condensation
    4. Coalescence
    5. Falling

Storms and Weather Systems

  • Air Masses: Large volumes of air with uniform temperature and moisture.
  • Fronts: Zones of transition between air masses.
  • Tropical Cyclones: Develop in homogenous air masses, driven by water vapor and heat.

Climate Zones and Types

  • Koppen Classification: Widely used system based on temperature and precipitation averages.
  • Main Climate Types:
    1. Tropical Humid
    2. Dry
    3. Mid-Latitude
    4. Severe Mid-Latitudes
    5. Polar
    6. Highland

Climate Change

  • Long-term changes influenced by natural cycles and human activity.
  • Reconstruction Techniques: Historical records, dendrochronology, ice cores, etc.
  • Milankovitch Cycles: Affect Earth's insolation and climate patterns.

Soils and Agriculture

  • Arable Land: Decreasing; concerns for agriculture sustainability.
  • Soil Composition: Minerals, air, water, organic materials.
  • Soil Layers (Horizons): Different layers provide specific functions.

Biosphere and Biogeography

  • Biogeography: Distribution of life on Earth.
  • Nutrient Cycles: Carbon, nitrogen, oxygen, and water cycles essential for life.