Comprehensive Study Guide With Review PDF

Lecture 1: Universe and Star Formation: The Big Bang occurred 14 billion years ago; only hydrogen and helium existed initially. Gravity pulls hydrogen into dense clouds, igniting nuclear fusion, forming stars and heavier elements. Large stars explode, creating nebulae that form new...

Lecture 1: Universe and Star Formation: The Big Bang occurred 14 billion years ago; only hydrogen and helium existed initially. Gravity pulls hydrogen into dense clouds, igniting nuclear fusion, forming stars and heavier elements. Large stars explode, creating nebulae that form new stars and planets. Every atom in your body was once in a star. Formation of Solar System: 4.6 billion years ago, rocky materials condensed to form planetesimals, eventually forming Earth. Inner planets (Mercury, Venus, Earth, Mars) formed from rocky materials; gas giants formed from volatile gasses. Our sun is about 4.5 billion years old and will expand and vaporize Earth in about 4 billion years. Formation of the Moon: Earth was struck by a Mars-sized object, leading to the formation of the Moon about 100 million years after Earth's formation. Atmosphere and Oceans: Early atmosphere mainly contained hydrogen and helium, most of which was lost to space. Water on Earth may have originated from asteroids or outgassed from Earth's interior. Early Earth likely had much more water, with oceans possibly submerging today's continents. Evolution of Life: First life appeared in oceans soon after Earth cooled and oceans filled. Oxygen atmosphere formed 3 billion years ago due to bacterial photosynthesis. Lecture 2 & 3: Seafloor Morphology: Major features: continental shelf, abyssal plains, mid-ocean ridges, seamounts. Oceanic crust is thinner and denser than continental crust, creating low areas for ocean basins. Plate Tectonic Theory: Developed from evidence of seafloor spreading and subduction. Continental drift theory, proposed by Alfred Wegener in 1915, was initially rejected due to lack of a valid mechanism (tidal action was incorrect). Discovery of mid-ocean ridges and magnetic anomalies provided strong evidence for plate tectonics. Plate Boundaries: Divergent Boundaries: Plates move apart (e.g., mid-ocean ridges, East African Rift Zone). Convergent Boundaries: Plates collide; oceanic crust subducts under continental crust, forming trenches and volcanoes (e.g., Andes). Transform Boundaries: Plates slide laterally (e.g., San Andreas Fault). Marine Sediments: Sediments accumulate slowly (centimeters per thousand years), providing a record of ocean productivity, temperature, and past extinction events. Sediment Types: River-borne, continental dust, biological material; red clays in open oceans, calcareous/siliceous sediments in high productivity areas. Mass Extinction Events: Five past extinction events; current human activity may be causing the sixth mass extinction. Lecture 4, 5 & 6: Ocean Waves 1. Fundamental Wave Principles: ○ Wavelength: Distance between crests. ○ Wave Speed: Distance traveled per unit time. ○ Wave Period: Time for one wavelength to pass. ○ Wave Frequency: Number of crests passing per unit time. 2. Wave Addition: ○ Constructive Interference: Waves add to create larger amplitude. ○ Destructive Interference: Waves cancel each other out. 3. Wave Propagation: Waves transmit energy, not mass. 4. Wave Speed: ○ Deep-Water Waves: Speed depends on wavelength.  ○ Shallow-Water Waves: Speed depends on water depth. ○ Intermediate Waves: Complicated by both wavelength and depth. 5. Wave Refraction: ○ Occurs when wave fronts bend as they slow down in shallower water, focusing energy on headlands and defocusing it in bays. Longshore Transport and Breaking Waves 1. Longshore Sediment Transport: Waves hitting the beach at an angle move sand along the shore. 2. Breaking Waves: As waves approach shallow water, they slow down, steepen, and eventually break. 3. Seasonal Beach Changes: ○ Summer: Gentle waves create wide sandy beaches. ○ Winter: Storm waves erode beaches, forming rocky shorelines. 4. Rip Currents: Fast-moving water channels that can pull swimmers offshore; escape by swimming parallel to the shore. Wave Height and Special Waves 1. Factors Determining Wave Height: ○ Wind Speed: Sets maximum wave height. ○ Wind Duration: Longer wind events increase wave height. ○ Fetch: Distance over which wind blows without obstruction. 2. Tsunamis: ○ Generated by seafloor movement (e.g., tectonic activity). ○ Can travel at speeds up to 500 mph. Ocean Tides 1. Equilibrium Theory of Tides: ○ Daily tidal patterns: Diurnal: One high and one low tide per day. Semidiurnal: Two equal high and low tides per day. Mixed Semidiurnal: Two unequal high and low tides per day. ○ Monthly tidal patterns: Spring Tides: Sun and moon align (new/full moon), causing higher tides. Neap Tides: Sun and moon are at right angles (quarter moon), causing lower tides. 2. Dynamic Theory of Tides: ○ Tides are influenced by the Coriolis force and ocean basin geometry. ○ Tidal bulges lag behind the moon due to friction with the seafloor. ○ Rotary tides are caused by the Coriolis force, leading to circular tidal patterns in ocean basins. Lecture 7, 8, & 9: Overview of Observed Patterns 1. Surface Wind Patterns: ○ Three main wind belts in each hemisphere: 0º-30º, 30º-60º, and 60º-90º. ○ Wind belts alternate directions. 2. Surface Ocean Temperature: ○ Warmest water along the equator, particularly in the western ocean basins. ○ Coldest water near the poles. 3. Surface Ocean Salinity: ○ Highest salinity in subtropical regions. ○ The Atlantic Ocean is saltier than other oceans. ○ North Pacific is one of the freshest regions. 4. Surface Ocean Currents: ○ Large subtropical gyres rotate clockwise in the northern hemisphere, counterclockwise in the southern hemisphere. ○ Antarctic Circumpolar Current moves eastward around Antarctica. 5. Deep Ocean Circulation: ○ Cold surface water sinks at high latitudes, moves to lower latitudes at depth, and returns to the surface through vertical mixing. Coriolis Force 1. Effect: ○ In the northern hemisphere, the Coriolis force deflects motion to the right. ○ In the southern hemisphere, it deflects motion to the left. ○ It is a result of the Earth’s rotation and the conservation of angular momentum. Atmospheric Circulation 1. Heating: ○ The Earth's surface absorbs sunlight, warms up, and emits infrared radiation, heating the atmosphere from below. ○ Warm air rises, cools as it ascends, and condenses, driving convection. 2. Hadley Circulation: ○ Warm air rises at the equator, cools and sinks at about 30º latitude, creating areas of high and low pressure that drive wind patterns. ○ This circulation influences global climate and sea-level pressure patterns. Vertical Ocean Structure 1. Thermocline: ○ The thermocline separates the warm surface layer from the cold deep layer.  ○ Permanent thermocline exists around 500 meters deep, while a seasonal thermocline forms in summer and disappears in winter. 2. Surface Salinity and Temperature: ○ Surface salinity is influenced by the exchange of freshwater between the ocean and atmosphere through evaporation and precipitation. ○ Surface temperature is a result of the exchange of heat across the air-sea boundary, with sunlight adding heat and evaporative cooling often driving heat loss. Wind-Driven Surface Circulation 1. Ekman Transport: ○ The movement of water in the Ekman Layer (about 50-100 meters thick) is 90 degrees to the right of the wind direction in the northern hemisphere and 90 degrees to the left in the southern hemisphere. 2. Geostrophic Currents: ○ Created when the Coriolis force balances the pressure gradient, causing water to flow along lines of constant pressure in a circular pattern around mounds of water, forming subtropical gyres. 3. Western Boundary Currents: ○ Strong, fast currents on the western side of subtropical gyres (e.g., the Gulf Stream), transporting warm water from the tropics to high latitudes. ○ Eastern boundary currents are slower and bring cold water from high latitudes toward the tropics. Equatorial and Coastal Upwelling 1. Equatorial Upwelling: ○ Trade winds drive surface water away from the equator, causing deep, nutrient-rich water to rise to the surface. 2. Coastal Upwelling: ○ Winds blowing parallel to the coast push surface water offshore, allowing deeper water to rise and replace it. Deep Ocean Circulation and the Global Conveyor Belt 1. Deep Water Formation: ○ Cold, dense water sinks in the North Atlantic and around Antarctica to form deep abyssal water. 2. Global Conveyor Belt: ○ Deep water flows from the North Atlantic, merges with Antarctic water, and circulates through the global ocean, returning to the surface to transport heat and regulate global climate. ○ Western boundary currents play a key role in transporting heat to higher latitudes. Lecture 10: El Niño Southern Oscillation (ENSO): 1. El Niño: ○ Originally described by Peruvian sailors in the 18th-19th centuries, referring to a warm southward current appearing near Christmas off the Peruvian coast. ○ Occurs roughly every 3-7 years, involving prolonged (8 months) warming of coastal waters off Peru and Ecuador. 2. Southern Oscillation: ○ Discovered by Sir Gilbert Walker in the 1920s; it describes a periodic reversal in atmospheric pressure patterns between Darwin, Australia, and Tahiti. ○ This east-west atmospheric circulation is called the Walker Circulation. 3. ENSO: ○ The coupling of El Niño (oceanic warming) and the Southern Oscillation (atmospheric pressure changes) leads to the phenomenon known as ENSO. ○ ENSO impacts wind direction, precipitation patterns, and atmospheric pressure across the Pacific region. ENSO Phases: 1. Normal Conditions: ○ Trade winds transport warm water westward, forming a warm pool in the western Pacific. ○ Thermocline is shallow in the eastern Pacific, deeper in the western Pacific. 2. El Niño: ○ Trade winds weaken or reverse, reducing equatorial upwelling. ○ Warm water spreads eastward, causing significant warming in the eastern Pacific. ○ Impacts include drought in Indonesia/Australia and increased rainfall in South America. 3. La Niña: ○ Opposite of El Niño; characterized by stronger trade winds, enhanced upwelling, and cooling in the eastern Pacific. Impacts of ENSO: 1. Direct Impacts: ○ Precipitation and Storms: El Niño causes drought in Australia and Indonesia, but increases rainfall in the central and eastern Pacific. ○ Hurricanes: El Niño increases hurricanes in the eastern Pacific but decreases hurricanes in the Atlantic due to increased wind shear. La Niña has the opposite effect: fewer hurricanes in the eastern Pacific,  more hurricanes in the Atlantic. ○ Ocean Productivity: El Niño reduces ocean productivity off the coast of Peru and Ecuador due to the reduced upwelling of nutrient-rich waters. 2. Global Climate Impacts: ○ Changes in the jet stream's position during ENSO affect weather patterns worldwide. ○ El Niño causes global temperatures to rise as warm water spreads across the equatorial Pacific. Other Natural Climate Oscillations: 1. North Atlantic Oscillation (NAO): ○ Affects the strength of westerly winds and pressure differences between Iceland and the Azores. ○ Positive Phase: Strong westerly winds, located northward. ○ Negative Phase: Weaker westerly winds, located southward. 2. Atlantic Multi-Decadal Oscillation (AMO): ○ A pattern of temperature variability in the North Atlantic, with warm and cool phases lasting several decades. 3. Pacific Decadal Oscillation (PDO): ○ Long-term climate pattern affecting the North Pacific and equatorial Pacific. ○ Positive Phase: Cooler North Pacific, warmer equatorial Pacific. ○ Negative Phase: Warmer North Pacific, cooler equatorial Pacific. 4. Arctic Oscillation (AO): ○ A climate pattern that influences weather in the Arctic region and across the Northern Hemisphere. Human-Caused Global Warming: Natural climate oscillations like ENSO, NAO, AMO, and PDO are superimposed on a long-term warming trend driven by human-caused global warming.