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GEO110 Lecture 1 Notes
Atmospheric Temperature Criterion (Chapter 3) Thermosphere (80 to 480 Km) ➢ Temperatures rise sharply in the thermosphere to 1200°C and higher due to greater degree of ionization and intense solar radiation which excites individual molecules to a high level of vibration leading to high temperatures (kinetic energy). Despite such high temperatures the thermosphere is not hot. This is because there is little to no gases/air to absorb the kinetic energy into heat (capacity to contain energy) leading to a cold thermosphere. ➢ Temperature inversion with increasing altitude. Mesosphere (50 to 80 Km) ➢ Mesosphere is made of ice crystals and contains very thin air. ➢ The Mesosphere’s outer boundary, the menopause is the coldest portion of the atmosphere, averaging -90°C. Stratosphere (18 to 50 Km) ➢ Temperature inversion with increasing altitude from -57°C at Tropopause to 0°C at Stratopause. ➢ Contains Ozone layer. There has been a relationship between the increase of chlorofluorocarbons (CFC) and decrease of ozone (O 3 ) concentrations. Troposphere (0 to 18 Km) ➢ The troposphere is the final layer encountered by incoming solar radiation and is the home of the biosphere (atmospheric layer that supports life, and region if principle weather activity. ➢ Approximately 90% of the total mass of the atmosphere and the bulk of all water vapour, clouds, and air pollution occurs within the troposphere. ➢ Temperature decreases rapidly with increasing altitude at an average of 6.4°C or 0.04% per 1000 meters, a rate known as the normal lapse. ➢ Tropopause is where thermal conditions stabilizes Earth’s four “Spheres” (Chapter 1) Atmosphere ➢ The atmosphere is a thin gaseous veil surrounding Earth, held in place above the planet by the force of gravity. ➢ Formed by gases arising from within Earth’s crust interior and the exhalation of all life over time.
➢ It is a combination of nitrogen (78%), oxygen (21%), carbon dioxide (0.039%) and trace gases such as argon, water vapour, methane, helium and sulfur dioxide. Hydrosphere ➢ Hydrosphere contains of: any water sources such as water that exist in the atmosphere, on the surface and in the crust near the surface, riverine, lacustrine (combination of lakes, ponds and wetlands), palustrine, lagoon (part of ocean enclosed by land), oceans etc. ➢ The portion of the hydrosphere that is frozen is the cryosphere, which is slowly diminishing. Geosphere ➢ The geosphere is the solid Earth, which consists of the core, mantle and crust. ➢ The core is between 6000-7000°C, consists of iron and nickel and is a solid due to increased pressure. ➢ The outer mantle is colder more solid while the inner mantle is plastic more fluid. The mantle consists of about 80% of the Earth. The asthenosphere is a weak fluid which is made of molten rock and can easily drift. ➢ The crust is the thinnest layer of the Earth. There are two types of crust: Continental and oceanic Biosphere ➢ The biosphere is the area in which physical and chemical factors (nutrient cycles) form the context of life. The biosphere include both flora and fauna and is very diverse such as the Amazon and Congo. Earth’s Systems Concept (chapter 1) Systems concepts ➢ There are two types of systems: closed and opened. ➢ A closed system is a system that is self-sustained and contained, no interactions with excessive elements. ➢ An open system is a system that has inflow and outflow of both energy and matter. This system also has complex and dynamic interactions with external environments. ➢ Examples: gases in air interact with biosphere, nitrogen fixation and denitrification, Geosphere interacts with atmosphere through volcanoes, volcanic eruptions cause blanket of ash in the atmosphere which reflect sunlight leading to less sun, geosphere interacts with biosphere when ash from volcanic eruptions interfere with plant photosynthesis. System Feedback ➢ Positive feedback: Change in system increases or worsens original effect.
Methods of heat transfer ➢ Conduction is the molecule-to-molecule transfer of heat energy as it diffuses through a substance. Incoming solar radiation is interrupted by objects which are heated up and begin to vibrate, the molecules or atoms in the atmosphere are excited, which generate heat by contact of nearby molecules. ➢ Convection is the transfer of heat by mixing or circulation. The physical movement of electrons from one location to another. ➢ Radiation is the transfer of heat in electromagnetic waves. Waves of radiation do not need to travel through a medium in order to transfer heat. Principle Temperature Controls (chapter 5) Factors that influence temperature ➢ Latitude: Further you go from the equator the cooler it gets. ➢ Altitude: Temperature decreases with increasing altitude within the troposphere. ➢ Distance from sea: With increasing distance from the sea-coast, there is a corresponding increase in the seasonal variation of temperatures. ➢ Prevailing winds: Temperature is dependant of the direction that the wind blows from. GEO110 Lecture 2 Notes Wind Essentials (chapter 6) Air pressure Measurements ➢ Wind is air in motion which is caused by differences in pressure systems. Low pressure is the outer movement of air while high pressure is the inflow of air. Pressure can be measured using an instrument called a barometer (baros meaning weight). There are two types of barometers: mercury or aneroid ➢ The barometer was discovered in 1643 by Evangelista Torricelli. The mercury barometer works with a long tube of mercury while the aneroid barometer does not require a meter long tube of mercury (aneroid means using no liquid). Wind measurements (chapter 6) Anemometer ➢ An anemometer measures wind speed Wind vane ➢ A wind vane determines wind direction; the standard measurement is taken 10 meters above the ground to reduce the effect of local topography.
➢ Meridians move from north to south and are measured in degree, min and sec. Every
15 degrees is equivalent to 1 hour (west subtract east add) ➢ GIS (geographic information system) -system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data.
Driving forces within the atmosphere (chapter 6) Pressure gradient force ➢ This force drives air from areas of higher pressure (dense air) to areas of lower pressure (less-dense air). Strongly subsiding and diverging air is associated with high pressure, and strongly converging and rising air is associated with low pressure. ➢ An isobar is an isoline (a line along which here is a constant value) plotted on a weather map to connect points of equal pressure. ➢ A steep gradient cause faster air movement from a high-pressure are to a low-pressure area. Isobars spaced wider apart from one another mark a more gradual pressure gradient, one that creates a slower airflow. ➢ Along a horizontal surface, a pressure gradient force that is acting alone produces movement at right angles to the isobars, so wind blows across the isobars from high to low pressure. Coriolis force ➢ This force is a deflective force that makes wind travelling in a straight path appear to be deflected in relation to Earth’s rotating surface. ➢ Since Earth rotates eastward, such objects appear to curve to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. ➢ The strength of this deflection varies, being weakest at the equator and strongest at the poles. Frictional Force ➢ The friction force drags on wind as it moves across Earth’s surfaces, but decreases with height above the surface. Geostrophic Winds ➢ These winds move parallel to isobars due to the difference between Coriolis and pressure gradient force High and low pressure systems ➢ In the Northern Hemisphere, surface winds spiral out from a high pressure area (very dense closely packed isobars, high winds, steep gradient and cold) in a clockwise direction, forming an anticyclone, and spiral into a low pressure system (wide isobars, warmer and lighter) in a counter clockwise direction, forming a cyclone. ➢ In the Southern Hemisphere, these circulation patterns are reversed, with winds flowing counter clockwise out of an anticyclonic high pressure cells (warmer, lighter and non- steep gradient gradual) and clockwise into cyclonic low pressure cells (very dense closely packed isobars, high winds and cold). Atmospheric Patterns of Motion (chapter 6) Occluded front ➢ When two air masses with different temperatures
showers Mistreal ➢ 85 miles per hour winds Santa Ana ➢ Blows dry and hot air from deserts to regions around the coast Chinook ➢ Strong warm and dry winds that blow from south or west in rocky mountain region Papero ➢ Blows from Andes mountains in South America Sirocco ➢ String scorching winds, iron stained sand produces red rain Monsoon ➢ Vary according to seasons, changes direction of wind movement. In summer cooler while in winter cooler air blows from land to sea creating drier weather conditions. Jet streams ➢ Jet streams are irregular concentrated bands of wind occurring at several different locations that influence surface weather systems. ➢ Appear 6 miles above the surface of the earth, approximately 2 km thick and between 160 to 480 km wide Land and sea breezes ➢ Land gains heat energy and warms faster than the waters offshore during the day. Because warm air is less dense, it rises, creating a lower pressure area that triggers an onshore flow of cooler marine air to replace the rising warm air – the flow is usually strongest in the afternoon, forming a sea breeze. ➢ At night, land cools, by radiating heat energy, faster than offshore waters do. As a result, the cooler air over the land subsides (sinks) and flows offshore towards the lower pressure area over the warmer water, where the air is lifted. Cloud Types and Identification Clouds ➢ An English biologist and amateur meteorologist Luke Howard wrote an article titled "On the modification of clouds" and established a classification system for clouds in
➢ Cloud formation is transient and do not have rigid forms. Altitude and shape are key to cloud classification. Stratus and Nimbostratus (low clouds)
➢ Low clouds made of water vapour, height is up to about 2000 m (6,500 feet). Stratus (Latin for “layer”). Stratus clouds appear dull, gray, and featureless. ➢ When they yield precipitation, they become nimbostratus (nimbo –denotes “stormy” or “rainy”) and their showers typically fall as drizzling rain. Stratocumulus (low clouds) ➢ Low clouds made of water vapour, height is up to about 2000 m (6,500 feet). Cumulus (Latin for “Heap”). Stratocumulus clouds are soft gray, globular masses in lines, groups or waves. They have heavy rolls and irregular overcast patterns. Altocumulus (middle clouds) ➢ The prefix alto –meaning high denotes middle-level clouds. These clouds are made of water droplets, height of about 2000 to 6000 m (6,500 to 20,000 feet). Altocumulus clouds appear like patches of cotton balls arranged in groups, rippling waves and associated with mountains. Altostratus (middle clouds) ➢ The prefix alto –meaning high denotes middle-level clouds. These clouds are made of water droplets, height of about 2000 to 6000 m (6500 to 20,000 feet). Altostratus clouds are thin to thick layered clouds with visible grey color and have no halos. Suns outline just visible through clouds on a gray day. Cirrus (High clouds) ➢ High clouds made of ice, height of about 6000 to 13,000 m (20,000 to 43,000 feet). Cirrus (Latin for “curl of hair”). These clouds appear like mares tails, wispy, feathery, with delicate fibers, streaks or plums. Cirrostratus (high clouds) ➢ High clouds made of ice, height of about 6000 to 13,000 m (20,000 to 43,000 feet). Cirrus (Latin for “curl of hair”). These clouds look like veils formed from fused sheets of ice crystals, having a milky look, with sun and moon halos. Cirrocumulus (high clouds) ➢ High clouds made of ice, height of about 6000 to 13,000 m (20,000 to 43,000 feet). Cirrus (Latin for “curl of hair”). These clouds look are dappled in small white flakes or turfs. They occur in lines or groups, sometimes in ripples, forming a “mackerel sky” Cumulus (vertically developed clouds)
downward movement and deposition of finer particles and minerals from the upper horizon of the soil, occurs in B horizon) occur. Therefore soil becomes laterite (rich in gravels and highly porous) ➢ Examples: Amazon, Congo and Brazil Tropical Monsoon ➢ This climate features a dry season that lasts 1 or more months. Rainfall brought by the ITCZ falls in these areas from 6 to 12 months of the year. The dry season occurs when ITCZ has moved away so that the convergence effect are not present. ➢ These climates experience a variation in temperature and precipitation ➢ An example of this kind of climate is Yangon, Burma of Myanmar (high annual temp) and the bay of Bengal which is affected significantly by rainfall approx. 515 cm Tropical Savana ➢ This climate exists pole ward of the tropical rain forest. The ITCZ reaches these climate regions for about 6 months or less of the year as it migrates with the summer sun. ➢ Summers are wetter than winters because convectional rain accompanies the shifting ITCZ when it is overhead. ➢ Temperature vary more in this climate than in tropical climate. This climate experiences two temperature maximums during the year because the suns direct rays are overhead twice, before and after the summer solstice ➢ This climate contains a mixture of trees and grasslands and supports lots of wild life (flora and fauna) ➢ Examples: Serengeti plain, Arusha Tanzania, Ambrosial National park and Masai Mara National park Humid Subtropical ➢ These climates either are moist all year or have a pronounced winter-dry period. Warm moist, unstable air produces convectional showers over land (some may be heavy). In fall, winter, and spring, maritime tropical and continental polar air masses interact, generating frontal activity (cyclones). ➢ Examples: Eastern and Southern Asia, Nagasaki Japan –humid and hot summer, Colombia and South Carolina Marine West Coast ➢ This climate features mild winters and cool summers, characteristic of Europe and other middle –to high latitude west coasts (USA). This climate has cool, moist unstable air masses. Weather systems forming along the polar front and maritime polar air masses move into these regions throughout the year, making weather unpredictable. ➢ Coastal fog, annually totalling 30 to 60 days. Heavy rain on coast side/wind ward and no rain on leeward/rain shadow side. Another word for a mountain is Cordillera ➢ Examples: Chilli, Australia, B.C, Aleutians, Alaska Mediterranean Dry-summer
➢ At least 70% of annual precipitation occurs during the winter months. Bands (coulombs of air) of cells of subtropical high pressure that blocks moisture carrying wind. This
Introduction ➢ Endogenic System: Consists of processes operating in Earth’s interior, driven by heat and radioactive decay, results in initial landforms. ➢ Exogenic System: Consists of processes operating at Earth’s surface, driven by solar energy and the movement of air, water and ice, results in sequential landforms ➢ Another word for mountain building is Orogeny Earth’s Crust ➢ Continental crust: made of 50 – 75% Silicon and Aluminium (SIAL), High viscosity, Lighter in weight and less dense, feldspar decomposes into clay ➢ Oceanic crust: made up of 50% or less silicon and MAFIC, low viscosity due to water saturation, heavier in weight and denser, Gabbro basalt ➢ Asthenosphere: Region of the upper mantle just below the lithosphere; the least rigid portion of Earth’s interior and known as the plastic layer, flowing very slowly under extreme heat and pressure. Plate Tectonics Continental drift ➢ Alfred Wegener a German scientist proposed the idea of Pangea (Greek for “all lands) ➢ Laurasia was the northernmost of two supercontinents that formed part of the Pangaea supercontinent around 300 to 200 million years ago ➢ In paleogeography, Gondwanaland, is the name given to the more southerly of two supercontinents that were part of the Pangaea supercontinent that existed from approximately 510 to 180 million years ago Plate Boundaries ➢ A fault is a crack in the Earth’s crust resulting from the movement of two plates or a boundary in which two separate plates meet. In a fault the footwall is the more stable side. Uptrust is when hanging wall is above the footwall. ➢ Plate boundaries fall into three categories: Convergent, Divergent and transform. ➢ Divergent boundaries are plates which are moving away from each other. They can either be oceanic plates or continental plates. At a divergent boundary, volcanic activity is common because mantle easily moves to the surface through the thin fractured rock as it separates. When a divergent boundary is on the ocean floor, a mid ocean ridge is formed. If a continent happens to be a place where a divergent boundary occurs, then the continent will begin to be torn apart as the sides of the plate separate creating a rift valley. The African rift valley in East Africa is an example of this occurrence. During this boundary volcanos and mild earthquakes occur. ➢ A convergent boundary is a boundary where two separate plates are pushing into each other. There are three types of convergent boundaries: continent-continent plate collision, continent-oceanic plate collision and ocean-ocean plate collision. In a continent-continent plate collision both sides of the convergent boundary have the same properties, which means that neither side of the boundary want to sink into the mantle and as a result both plates will crumple up as they collide forming a high mountain range much like the Himalayas. In a continent-oceanic plate collision,
continental crust pushes up against oceanic crust, since the oceanic crust is heavier/denser than the continental crust it sinks below the continental crust into the mantle. This creates a trench. This area of sinking where the two plates meet is called a subduction zone. When one plate is forced under the other one it begins to melt and a line of volcanos form in a parallel line to the trench. The line of volcanos will then become volcanic mountains like the Andes Mountain in South America or the Cascade Range in the Western US or Sydney. The last type of convergent boundary is ocean- ocean plate collision. In this case both plates have the same properties, which means they both want to sink. When the oceanic plate converge one runs over top the other causing it to sink into the mantle and form a subduction zone. Once again when one plate is forced under the other one it begins to melt and a line of volcanos form in a parallel line to the trench. The line of volcanos will then become islands like the Philippines or Hawaii or the Japanese Islands. All types of converging will form volcanos and strong earthquakes. ➢ A transform boundary is a boundary where two plates slide past each other. The most famous example of transform boundary is the San Andreas Fault in California. At this type of boundary the only effects are Earthquakes since the sliding process is not smooth, there is no mountains or volcanos forming at this type of boundary. Evidence about continental movement ➢ AS OF NOW UNKNOWN Earthquakes ➢ Earthquakes are a result of continuous stress accumulation and strain release along faults. ➢ Seismic waves are waves of energy that travel through the Earth's layers, and are a result of an earthquake. There are two types: P and S. The faster of these body waves is called the primary or P, as it spreads out it pushes (compresses) pulls (dilates) he rock. These P waves are able to travel through either solid rock, such as Granite Mountains or liquid material, such as volcanic magma or the water of the oceans. This wave causes less damage because they are vertical. The slower through the body of rock is called the secondary or S wave. As an S wave propagates, it shears the rock sideways at right angles to the direction of travel. This creates more damage because it moves horizontally. ➢ Seismography is an instrument used to detect and record the ground motion that occurs during an earthquake. This instrument determines the direction of wavelength (size of earthquake) ➢ Modified Mercalli scale is a Roman-numeral scale from 1 to 10 that ranges from earthquakes that are barely felt (lower numbers) to those that cause catastrophic total destruction (higher numbers). This scale measures index of damage. ➢ The Richter scale measures the magnitude of the earthquake (amount of energy released by wave motion) on a scale from 1 to 10, biggest is the Fukushima Daiichi.
