oceanography (copy)
Coriolis Effect on Air Currents, Ocean Currents, and Hurricanes:
The Coriolis Effect is a result of the Earth's rotation. It causes moving air and water to curve to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. In the context of air currents, this deflection influences the direction of prevailing winds, such as the trade winds and westerlies. In ocean currents, it affects the direction of major oceanic gyres. In the case of hurricanes, the Coriolis Effect is responsible for the rotation of these storms, with counterclockwise rotation in the Northern Hemisphere and clockwise rotation in the Southern Hemisphere.
Charles' Law vs. Boyle's Law:
Charles' Law describes the relationship between the volume of a gas and its temperature, assuming constant pressure. It states that when the temperature of a gas increases, its volume also increases, and vice versa, as long as pressure remains constant.
Boyle's Law, on the other hand, describes the relationship between the pressure of a gas and its volume when the temperature is kept constant. It states that if the volume of a gas decreases, its pressure increases, and if the volume increases, its pressure decreases, provided that the temperature remains constant.
El Niño vs. La Niña:
El Niño is a climate phenomenon characterized by the periodic warming of sea surface temperatures in the central and eastern Pacific Ocean. It can lead to various global weather impacts, including increased rainfall and flooding in some regions and droughts in others.
La Niña is the opposite phenomenon, marked by cooler-than-average sea surface temperatures in the same region. It tends to result in contrasting weather patterns, such as increased hurricane activity in the Atlantic and drier conditions in some parts of the world.
ITCZ (Intertropical Convergence Zone):
The ITCZ is a region near the equator where the northeast and southeast trade winds converge. It is characterized by rising warm, moist air, which often leads to the development of thunderstorms and heavy rainfall. This convergence zone can shift slightly north and south with the changing seasons, influencing the wet and dry seasons in tropical and subtropical regions.
Low-Pressure vs. High-Pressure Systems:
Low-pressure systems are areas where the atmospheric pressure is lower than the surrounding areas. They are associated with rising air, which leads to cloud formation and often precipitation. Low-pressure systems typically bring unstable weather conditions.
High-pressure systems are areas where the atmospheric pressure is higher than the surrounding regions. They result in descending air, which inhibits cloud formation and tends to lead to fair weather with clear skies. High-pressure systems are associated with stable atmospheric conditions.
Northern vs. Southern Hemisphere Hurricanes:
Hurricanes in the Northern Hemisphere (e.g., the Atlantic and North Pacific) rotate counterclockwise. This means the winds circulate counterclockwise around the eye of the hurricane.
In the Southern Hemisphere (e.g., the South Pacific and South Indian Ocean), hurricanes, which are also known as cyclones or typhoons, rotate clockwise. The winds circulate clockwise around the eye of the storm.
Orographic Lifting and Precipitation:
Orographic lifting occurs when moist air is forced to rise over elevated terrain, such as mountains. As the air rises, it cools and condenses, leading to cloud formation and precipitation on the windward side of the mountain. This is why mountains are often associated with increased rainfall on one side (windward) and a rain shadow (dry) on the other side.
Biological Pump: The biological pump is a crucial process in the Earth's oceans that plays a vital role in the global carbon cycle. It describes the transfer of carbon from the surface ocean to the deep ocean through the actions of marine organisms. This process is primarily driven by phytoplankton, tiny marine plants, which use photosynthesis to convert carbon dioxide into organic matter. When these phytoplankton die or are consumed by other organisms, the organic matter sinks into deeper ocean layers, effectively transporting carbon from the surface to the deep ocean. This carbon sequestration helps regulate atmospheric carbon dioxide levels, making the biological pump a critical component of the planet's climate system.
Color of Productive Ocean Water: The color of productive ocean water typically appears greenish-blue or blue-green, and this hue is a visual indicator of the presence of phytoplankton, which are microscopic, plant-like organisms that thrive in nutrient-rich surface waters. The greenish tint arises from the chlorophyll pigments in phytoplankton, which they use for photosynthesis. The more chlorophyll-containing phytoplankton present, the more vibrant the greenish color of the water. Thus, the color of productive ocean water is an essential marker for the health and fertility of marine ecosystems, as it signifies areas where primary production and the marine food web are thriving.
Ocean Fertilization: Ocean fertilization refers to the intentional introduction of nutrients, typically iron or nitrogen, into specific oceanic regions to stimulate the growth of phytoplankton. This practice is undertaken with the goal of enhancing carbon capture from the atmosphere, as phytoplankton absorb carbon dioxide during photosynthesis. The idea behind ocean fertilization is to promote the growth of phytoplankton, which can then transfer carbon to the deep ocean through the biological pump. However, it is a controversial and highly regulated technique, as its environmental impacts are not fully understood, and improper fertilization can lead to unpredictable ecological consequences.
Carbon Sequestration: Carbon sequestration is the process of capturing and storing carbon dioxide from the atmosphere, thus preventing it from contributing to global warming and climate change. In the context of the ocean, carbon sequestration can be achieved through various methods, such as the biological pump, in which marine organisms transport carbon from the surface to the deep ocean. Other ocean-based carbon sequestration methods involve creating artificial reefs, restoring coastal wetlands, and conserving and protecting natural marine habitats. These approaches aim to reduce the amount of carbon dioxide in the atmosphere by storing it within ocean ecosystems, helping mitigate the impacts of climate change.
Ocean Acidification: Ocean acidification is a significant consequence of increased carbon dioxide levels in the atmosphere. When carbon dioxide is absorbed by seawater, it reacts with water to form carbonic acid. This process lowers the pH of the ocean, making it more acidic. Ocean acidification has detrimental effects on marine life, particularly organisms with calcium carbonate shells or skeletons, such as corals, mollusks, and some types of plankton. The more acidic conditions hinder their ability to build and maintain their protective structures. This phenomenon poses a substantial threat to marine ecosystems, as it disrupts food chains and has far-reaching ecological and economic implications.
Ekman Spiral: The Ekman spiral is a theoretical model describing the distribution of water velocities in the ocean as a function of depth and distance from the wind's surface. It's named after the Swedish physicist Vagn Walfrid Ekman. In the Northern Hemisphere, it describes how water moves to the right of the wind direction at the surface and gradually spirals clockwise with depth. In the Southern Hemisphere, it's mirrored, with counterclockwise spiraling. The Ekman spiral characterizes the transition from surface flow driven by wind to deeper currents influenced by Coriolis and friction.
Ekman Transport: Ekman transport is the net movement of water perpendicular to the wind direction, due to the frictional interaction between wind and the ocean surface. In the Northern Hemisphere, the Ekman transport is to the right of the wind, and in the Southern Hemisphere, it's to the left. The net effect of Ekman transport is to create a convergence of water towards the center of subtropical gyres and divergence at high latitudes, contributing to the formation of geostrophic currents.
Coastal Upwelling and Downwelling:
Coastal Upwelling: Coastal upwelling is a phenomenon in which deep, nutrient-rich waters rise to the surface along coastlines. It occurs when surface winds blow parallel to the coast, pushing surface waters offshore. This, in turn, leads to the upwelling of cold, nutrient-rich water from the deeper ocean layers. Coastal upwelling regions are often biologically productive as the nutrient-rich water supports thriving marine ecosystems.
Coastal Downwelling: Coastal downwelling is the opposite of upwelling. It occurs when surface winds blow onshore, causing surface water to converge and sink. Downwelling typically leads to warmer surface waters and is often associated with lower biological productivity in the coastal zone.
Langmuir Circulation:
Langmuir circulation refers to a pattern of wind-driven, counter-rotating, parallel rows of circulatory cells on the ocean's surface. These cells are elongated, tube-like structures and are a result of the interaction between the wind and the ocean surface. Langmuir circulation is a common phenomenon in the open ocean and is responsible for the formation of distinctive surface patterns or streaks.
Formation of Eddies:
Eddies are circular, rotating water masses within the ocean that can vary in size and intensity. They are often generated by the interaction of complex ocean currents, such as the Gulf Stream, and are important for redistributing heat, nutrients, and properties within the ocean. Eddies can be formed through a variety of mechanisms, including instability in ocean currents, interactions with topography, or wind-driven processes.
Gyres and Geostrophic Current Formation:
Gyres are large, rotating oceanic circulation systems that are driven by a combination of factors, including the Coriolis effect and wind patterns. They can be found in each major ocean basin and are responsible for the movement of surface waters in a circular manner. Geostrophic currents are the result of a balance between the Coriolis effect and pressure gradients, resulting in horizontal currents that flow parallel to lines of constant pressure.
Importance of Gulf Stream, North Atlantic Deep Water, and Antarctic Bottom Water:
The Gulf Stream is a powerful warm ocean current in the North Atlantic Ocean. It plays a critical role in redistributing heat, influencing climate, and impacting weather patterns along the East Coast of North America and Western Europe.
North Atlantic Deep Water (NADW) is a deep, cold, and dense water mass formed in the North Atlantic. It is a crucial component of the global thermohaline circulation and contributes to the transportation of heat and nutrients around the world's oceans.
Antarctic Bottom Water is a dense, cold water mass that forms near Antarctica and fills the deep ocean basins. It plays a vital role in the global ocean circulation, helping to maintain the distribution of ocean temperatures and influencing the Earth's climate system.
Antarctic Circumpolar Current:
The Antarctic Circumpolar Current is the world's strongest ocean current, flowing eastward around Antarctica. It acts as a barrier separating the cold Antarctic waters from warmer subtropical waters and is a key driver of global ocean circulation. It also plays a crucial role in regulating the exchange of heat and carbon dioxide between the ocean and the atmosphere.
Western vs. Eastern Boundary Currents:
Western boundary currents, such as the Gulf Stream in the North Atlantic, are warm, fast-flowing currents located on the western side of ocean basins. They transport warm water poleward and have a significant impact on regional climates and weather patterns.
Eastern boundary currents, like the California Current in the North Pacific, are cooler, slower-moving currents located on the eastern side of ocean basins. They transport cold, nutrient-rich water equatorward and support productive marine ecosystems.
Thermohaline Circulation:
Thermohaline circulation, also known as the "Great Ocean Conveyor Belt," is a global system of ocean currents driven by differences in temperature (thermo) and salinity (haline). It plays a crucial role in redistributing heat, nutrients, and dissolved gases throughout the world's oceans. The sinking and upwelling of water masses in this circulation system help regulate Earth's climate and the movement of heat around the planet. The formation of North Atlantic Deep Water and Antarctic Bottom Water are key components of thermohaline circulation.
Anatomy of a Wave:
Waves in the ocean can be broken down into several key components:
Crest: The highest point of the wave.
Trough: The lowest point of the wave.
Wave Height: The vertical distance between the crest and the trough.
Wavelength: The horizontal distance between two successive crests (or troughs).
Wave Amplitude: Half of the wave height, which is the distance from the wave's resting position (the still water level) to either the crest or the trough.
Wave Period: The time it takes for one complete wave (from crest to crest or trough to trough) to pass a fixed point.
Wave Frequency: The number of waves passing a point in one second. It is the reciprocal of the wave period.
Wave Refraction, Diffraction, and Interference:
Wave Refraction: Wave refraction is the bending of waves as they approach the shore or encounter variations in water depth. It occurs because one part of a wave may enter shallower water before another part, causing the wave to change direction. Refraction can lead to the concentration of wave energy on headlands and the divergence of energy in bays.
Wave Diffraction: Wave diffraction is the bending of waves around obstacles or through openings, such as when waves bend around a breakwater or a harbor entrance. It is characterized by the spreading of wave energy into areas where it might not have reached otherwise.
Wave Interference: Wave interference occurs when two or more wave trains meet and interact. Constructive interference results in larger waves, while destructive interference results in smaller or canceled-out waves.
Depths of Shallow vs. Deep Waves:
Shallow Waves: Shallow waves are characterized by a water depth (d) that is less than half of their wavelength (L). In shallow water, the wave speed is primarily determined by the depth, and the waves may "feel" the bottom. Wave speed is given by the square root of (gd), where g is the acceleration due to gravity.
Deep Waves: Deep waves have a water depth (d) greater than half of their wavelength (L). In deep water, wave speed is not influenced by the bottom, and the wave speed is determined by the wavelength and the period.
Capillary Wave, Seiche, Storm Surge, Rogue Wave, and Tsunami:
Capillary Wave: Capillary waves are very small ripples on the water's surface caused by surface tension. They are usually less than 1.73 cm in wavelength.
Seiche: A seiche is a standing wave in an enclosed or semi-enclosed body of water (like a lake or harbor) caused by a variety of factors, including wind, atmospheric pressure changes, or geological events.
Storm Surge: A storm surge is a temporary rise in sea level along the coast caused by strong onshore winds and low atmospheric pressure, typically associated with hurricanes or cyclones.
Rogue Wave: Rogue waves, or freak waves, are unexpectedly large and steep waves that can occur at sea. They are often much larger than the surrounding waves and can be very dangerous to ships.
Tsunami: Tsunamis are long-period ocean waves usually generated by underwater earthquakes, volcanic eruptions, or landslides. They can travel across entire ocean basins and, upon reaching shallower waters near the coast, can grow in height to become destructive.
Order of Sizes of Waves:
The order of sizes of waves, from smallest to largest, is typically as follows: capillary waves, wind-generated waves (including most ocean waves), seiches, storm surges, rogue waves, and tsunami waves (largest and most destructive).
Tsunami Warning Systems:
Tsunami warning systems include seismometers to detect undersea earthquakes, buoy networks to monitor sea level changes, and a communication system to disseminate warnings to coastal communities. Organizations like the Pacific Tsunami Warning Center and the National Tsunami Warning Center play a critical role in monitoring and issuing tsunami alerts.
Tidal Energy Systems:
Tidal energy systems harness the kinetic and potential energy of tides to generate electricity. They typically use underwater turbines or tidal stream generators placed in areas with strong tidal currents. These systems can help produce clean and predictable energy by converting the movement of water into electrical power.
Gravity Equation: The gravity equation, which describes the force of gravity between two objects, is given by Isaac Newton's law of universal gravitation. The equation is as follows:
�=�⋅�1⋅�2�2F=r2G⋅m1⋅m2
Where:
�F is the force of gravity between two objects.
�G is the universal gravitational constant.
�1m1 and �2m2 are the masses of the two objects.
�r is the distance between the centers of the two objects.
This equation explains how every object with mass in the universe attracts every other object with mass, and the force of this attraction is proportional to the product of their masses and inversely proportional to the square of the distance between them.
Aphelion, Perihelion, Apogee, Perigee:
Aphelion: Aphelion refers to the point in an object's orbit (typically a planet or comet) when it is farthest from the Sun. In Earth's orbit, the aphelion occurs in early July, making it the point in our planet's orbit farthest from the Sun.
Perihelion: Perihelion is the point in an object's orbit when it is closest to the Sun. For Earth, the perihelion occurs in early January, marking the closest approach to the Sun in our orbit.
Apogee: Apogee is the point in the orbit of a celestial body, like the Moon or a satellite, when it is farthest from the Earth. The Moon's apogee, for example, is the farthest point in its orbit from Earth.
Perigee: Perigee is the point in the orbit when a celestial body is closest to the Earth. For the Moon, the perigee marks the closest point in its orbit around our planet.
Force that Causes the Rotation of the Moon and Earth: The force that causes the rotation of the Moon and Earth is primarily their initial angular momentum. When the solar system formed, matter began to collapse and rotate under the influence of gravity. As this material condensed, the conservation of angular momentum led to the spinning of celestial bodies. For Earth, this initial spin is responsible for its daily rotation, and for the Moon, it is responsible for its synchronous rotation, where one side constantly faces the Earth while it orbits.
Tide-Generating Force: The tide-generating force is the differential gravitational attraction of the Moon and the Sun on different parts of the Earth. It causes the ocean's water to bulge, creating the tides. This force is the primary driver of tidal patterns. When the Sun, Moon, and Earth align (during full moons and new moons), their combined gravitational pull creates higher high tides, known as "spring tides." When they are at right angles (during the first and third quarter moons), they create lower high tides, known as "neap tides."
Spring Tide vs. Neap Tide:
Spring Tide: Spring tides occur when the Sun, Moon, and Earth are aligned during a full moon or a new moon. During spring tides, the gravitational forces of both the Sun and the Moon reinforce each other, resulting in higher high tides and lower low tides. This creates more significant tidal variations.
Neap Tide: Neap tides occur when the Sun, Moon, and Earth form a right angle during the first and third quarter moons. The gravitational forces of the Sun and the Moon partially cancel each other out, leading to lower high tides and higher low tides. Neap tides result in smaller tidal variations.
Diurnal, Semidiurnal, and Mixed Tide:
Diurnal Tide: Diurnal tides consist of one high tide and one low tide each day. They have a period of approximately 24 hours and 50 minutes, which is the time it takes for the Earth to complete one full rotation relative to the Moon.
Semidiurnal Tide: Semidiurnal tides have two high tides and two low tides each day. They occur in roughly 12-hour intervals, which corresponds to half of a lunar day. These tides are commonly observed in many coastal regions.
Mixed Tide: Mixed tides have characteristics of both diurnal and semidiurnal tides. They exhibit unequal high tides and low tides, with some days having one high and one low tide and others having two high and two low tides.
Top layer “surface mixed layer”: is often warm and without many nutrients
• Stratification: is the separation of surface waters and deep into layers by
distinct differences in temperature and salinity occurs when
• Salinity - driving mechanism for circulation in the deep ocean.
• Density: is a function of temperature and salinity.
• Thermohaline circulation: is driven by density and salinity.Ocean layers:
Surface
Central (from 0 to 1 km)
Intermediate
Deep water (> 2 km) , e.g. North Atlantic Deep Water (NADW), Pacific
Deep Water (PCD)*
Bottom water Atlantic Bottom Water