GEOG 102 Midterm 1 Review

Mid-Term Structure

• Examination consists of 10 multiple-choice questions and 7 short answer questions.
• Students must answer 5 short answer questions, each worth 4 marks.
• Responses should be written in full sentences; diagrams are encouraged for clarity.

Study Strategy

• Identify core concepts from each lecture.
• Utilize overview and summary slides to grasp broad topics.
• Review lecture slides and assigned textbook readings for additional context.
• Understand and compare concepts, such as metastable vs. dynamic equilibrium.

Earth System Science

• Focus on topics like human impact, open/closed systems, feedback loops, and equilibrium.

The Human Footprint

• Emphasizes sustainability across agriculture, energy, resources, and development.
• Examples include the impact of Belgian wind farms and deforestation in Rio de Janeiro.

Open vs. Closed Systems

• Open systems interact with their environment, having both inputs and outputs of energy and matter.
• Closed systems, like Earth regarding water and air, have limited resources and are relatively self-contained.

Feedback Loops

• Positive feedback amplifies changes, leading to greater deviations from the starting state, creating instability.
• Negative feedback moderates change, promoting stability and self-regulation within the system.

Equilibrium States

• Systems can reach equilibrium, maintaining balance over time.
• Types of equilibrium include:
  • Steady-state: Fluctuations around an average value.
  • Dynamic equilibrium: Changes in average values over time.
  • Metastable equilibrium: Resulting from abrupt transitions between states.

Earth's Axial Tilt

• The Earth's axis tilts at approximately 23.5° relative to the plane of the ecliptic, influencing seasonal changes.
• Earth's shape affects sunlight distribution, with sunlight spread over larger areas at the poles.

Milankovitch Cycles

• Variations in Earth's orbit and axial tilt affect climate and seasonal patterns over thousands of years.

Greenhouse Effect

• Longwave radiation from Earth is absorbed by greenhouse gases like CO2, H2O, and CH4, leading to increased atmospheric temperatures.
• Low, thick clouds generally cool the Earth by reflecting sunlight, while high, thin clouds trap heat.

Greenhouse Gases Sources

• Major sources of methane include rice cultivation, livestock waste, and fossil fuel usage.
• Nitrous oxide emissions are linked to motor vehicles and nitrogen fertilizers, with a long atmospheric lifetime of 121 years.

Residence Time of Gases

• CO2 has a prolonged residence time in the atmosphere, influenced by uptake rates from oceans, plants, and rock weathering.

Human Impact on Climate

• Current CO2 levels are historically similar to the Pliocene era (3-5 million years ago), when Arctic temperatures were significantly higher, and sea levels were notably elevated.

Heat Transfer Mechanisms

• Heat transfer occurs from hot to cold regions through:
  • Conduction: Direct transfer between molecules.
  • Radiation: Energy spread as electromagnetic waves.
  • Convection: Vertical energy movement in fluids.
  • Advection: Horizontal energy movement similar to convection.

Sensible vs. Latent Heat

• Sensible heat is the energy felt as temperature changes.
• Latent heat is the energy consumed or released during phase changes, such as when water freezes, releasing heat.

Principal Temperature Controls

• Key factors affecting temperature include:
  • Latitude: Distance from the equator.
  • Altitude/Elevation: Height above sea level.
  • Cloud Cover: Impacting solar radiation.
  • Proximity to Water Bodies: Water's specific heat moderates temperatures.