Lecture Notes: Ocean Waves and Interference

Recap of Previous Concepts

• Wavelength
• Wave Speed
• Wave Height
• Crest and Trough
• Period
• Wave Base
• Deep Water Waves vs. Shallow Water Waves
• Dispersion and Fetch

Types of Interference

Constructive Interference

• Occurs when two waves line up perfectly (crest to crest, trough to trough).
• Results in greater wave height.
• Known as "double ups" in surfing, where waves appear bigger.

Destructive Interference

• Occurs when the crest of one wave aligns with the trough of another, canceling each other out.
• Results in no wave.

Mixed Interference

• Combination of waves of different wavelengths and heights.
• Produces a complex wave pattern.
• Example: Longer period waves mixed with shorter period waves.

Visualizing Interference

• Earth Guide Diagrams (UCSD tool):
  • Shows combination of waves.
  • Red and green lines represent individual waves.
  • White line represents resulting wave from interference.
  • Users can manipulate wave speed, amplitude, and wavelength.

Rogue Waves

• Occur when ocean currents oppose wave directions, e.g., Agulhas Current vs. Antarctic storm waves.
• Can cause large waves dangerous to ships.
• Example: Perfect Storm movie portrayal.

Real-life Observations

• Outgoing tides at lagoons (e.g., San Elijo Lagoon, Batiquitos Lagoon) can enhance wave size.
• Surfers often observe larger waves in areas where outgoing currents meet incoming waves.

Final Recommendations

• Visit the UCSD website to experiment with wave interference simulations to deepen understanding.
• Observe natural examples at beaches to see wave phenomena in action.