Oceanography and Ocean Waves

Oceanography

• Oceanography studies the oceans, which cover most of Earth.
• Oceans are complex and dynamic environments interacting with the surrounding world.
• About 80% of Earth's living organisms are found in oceans.
• Oceans provide food, shelter, and transportation to terrestrial life.
• Oceanography involves many specialized sub-fields (chemistry, biology, physics, etc.)

Ocean Waves

• Ocean waves are movements of energy through water, mostly caused by wind.
• Wave energy makes water molecules move up and down, forming crests (high points) and troughs (low points).
• Waves travel in groups called wave trains.
• Waves break differently depending on the shoreline slope:
  • Spilling breakers on gently sloping shores.
  • Plunging breakers on steeply sloping shores.
• Types of waves include:
  • Tsunamis (caused by earthquakes or volcanic eruptions; highly destructive)
  • Wind waves (common, caused by wind friction, size depends on wind strength)
  • Ocean swells (large, mature waves from storms)
  • Tidal waves (large waves caused by tides, predictable)

Wave Properties

• Waves are propagating, oscillating deformations of a medium.
• Waves are described by wavelength, frequency, amplitude, period, crests, and troughs.
• Frequency is the number of wave cycles per second.
• Wavelength is the distance of one wave cycle.
• Wave speed equals wavelength times frequency.
• Longer wavelength means lower frequency.
• Period is the time for one wave cycle.
• Amplitude is the distance between wave midline and crest/trough.

Tsunamis

• Tsunamis are ocean waves from rapid seafloor displacement (earthquakes, landslides, volcanic explosions).
• They travel at high velocity, are wide, but only a few feet high out at sea.
• Tsunami height increases as they approach shore, causing powerful surges.
• Warning networks exist for the Pacific and Indian Oceans.

Ocean Currents

• Ocean currents are large-scale water movements globally.
• Two main types: surface and deep currents.
• Surface currents are primarily wind-driven, influenced by Earth's rotation (Coriolis effect).
  • Coriolis effect causes clockwise rotation in the Northern Hemisphere and counter-clockwise in the Southern.
• Deep currents are caused by density differences (temperature and salinity).
• Thermohaline circulation (global conveyor belt) involves temperature and salinity differences driving global water movement.
  • Transports nutrients and energy.

Upwelling

• Upwelling is the movement of deep ocean water to the surface.
• Wind drives water away from the shoreline, pulling deeper water upward.
• Coriolis effect further directs water movement (clockwise in N, counter-clockwise in S).
• Upwelling brings nutrients to the surface, aiding plankton growth.
• Upwelling zones are vital for ocean biodiversity and fisheries.
• Upwelling can relocate organisms from nesting grounds, affecting their survival, although resulting in rich fishing grounds.

Gyres

• Gyres are circular ocean currents created by surface currents and wind.
• The North Pacific Subtropical Gyre is the world's largest gyre, affecting weather patterns and having a garbage patch.
• Other current types: surface and deep (density-driven).
• Global weather patterns (Hadley Cells) include trade winds, westerlies, and easterlies.
• Upwelling happens near coastlines drawing nutrient-rich water.
• El Niño Southern Oscillation is a climate pattern with warmer water in the Pacific.
• Thermohaline circulation (global conveyor belt) cycles water globally.
• Ocean circulation regulates climate by distributing warm and cool water.

Earth's Atmosphere

• The atmosphere is a thin layer of gases surrounding Earth.
• Five layers: troposphere (weather), stratosphere (ozone), mesosphere (meteor burning), thermosphere (ISS), exosphere (atmosphere-space merge).
• Main gases: nitrogen (78%), oxygen (21%), and others (1%).
• Ozone in the stratosphere protects from UV radiation.
• Greenhouse gases (methane, carbon dioxide) trap heat, regulating Earth's temperature.

Ozone

• Ozone is a gas (O3) vital to protecting Earth from harmful UV rays.
• Ozone is present in the stratosphere (good) but also in the troposphere (bad, smog).
• CFCs (chlorofluorocarbons) damage the ozone layer.
• Montreal Protocol reduced CFC use and ozone layer is recovering.
• Ozone layer protects against sunburn, skin cancer, cataracts, and damages plant growth.

Thermal Energy and Expansion

• Thermal energy is energy from particle movement.
• Higher temperatures mean faster particle movement.
• Heat transfer methods: conduction (direct contact), convection (fluid movement), radiation (electromagnetic waves).
• Thermal expansion is a change in size or shape due to temperature.
• Solids, liquids, and gases all expand differently in response to changing temperatures based on mass, particle bonds, etc.
• The temperature change affects different types of matters in different ways.

Heat Capacity and Specific Heat

• Heat capacity is the heat absorbed to change temperature.
• Specific heat relates to heat capacity per gram of substance.
• Molar heat relates to heat capacity per mole.
• Water has a high specific heat, regulating Earth's temperature.
• Metals are good heat conductors.

Heat Transfer

• Heat is the transfer of kinetic energy and is measured by temperature.
• Heat always moves from warmer to cooler regions.
• Methods of heat transfer: conduction (contact), convection (fluid movement), radiation (electromagnetic waves).
• Conductors transfer heat quickly while insulators slow down heat transfer.

Solar Radiation

• Solar radiation is electromagnetic energy from the sun.
• Types: visible light, infrared, ultraviolet.
• Incoming solar radiation (measured in W/m²).
• Visible light ranges from red to violet (lowest to highest frequency).
• Infrared light has lower frequency than visible light.
• Ultraviolet light has higher frequency than visible light.