Physical Geo Notes Term 2 PDF

TERM 2 Coriolis Effect : -long distance → distance that the energy from the sun travels from the atmosphere; energy passes through much more atmosphere at the poles than the equator - more energy is lost or reflected by the atmosphere -only for wind travelling north-south south-north -caused by the...

TERM 2 Coriolis Effect : -long distance → distance that the energy from the sun travels from the atmosphere; energy passes through much more atmosphere at the poles than the equator - more energy is lost or reflected by the atmosphere -only for wind travelling north-south south-north -caused by the changing of speed in the rotation of the earth -further from the equator - experience hurricanes because the air has more time to bend -further from north pole - more rotation because greater distance from the equator (time to bend) Explaining variations in temp, pressure, winds : -latitude (most influential factor affecting temperature) - it determines how much insulation each of the area receives -angle of sun and thickness of atmosphere -land/sea distribution -oceans : 50% north, 90% south *land heats up and cools down faster because of density Why water heats more slowly : 1) Sun energy can penetrate deeper 2) Water constantly releases heat energy 3) Tides and currents allow heat to dispersed over an even great depth and area → tides = caused by the moon and the → currents = SURFACE ocean currents (Gyres); circular - caused by the influence of prevailing winds blowing across the ocean; -majority of the wind comes from one specific direction = wind blowing the same direction (prevailing winds) -Gyres interact indirectly with the atmosphere above it; very effective transporters of hot and cold and not overly fast -land masses is the other factor determining gyres → when they hit a land mass it blows them into another direction Ocean conveyor belt (bottom) - cold, salty water from polar regions sink into the depths and moves towards the equator; it will rise when it goes to warmer areas and vice versa *When it's warm, the materials rise, which is good for fishing karena the fishies naik to eat them and boom fishing season. -How it starts → glacier melts, it sinks when it mixes in the ocean – there’s always more glaciers melting and sinking so the conveyor belt just never stops. - north atlantic is warmer than the north pacific → leads to more evaporation in the north atlantic; this evaporation leaves more salt behind making water denser, which sinks -water will travel back to the north pacific, picking up more water which reduces the density - the melt water is a constant function Important points : 1) Does not exist at the surface; it can rise up and get close to the surface but rarely 2) It has sort of an engine = cold water 3) As it travels around the world, its depth can change; this water can rise up and down just like in the atmosphere because of heat; hot = rises 4) Moves slowly; one full lap takes a 1000 years -clockwise in NH, anti clockwise in SH *effect on temp depends upon temp of current -warm currents from the equator raise the temp of polar areas (with the aid of westerlies); cool current can bring cooler temperature -Distance from the sea influences temperature : water takes up heat and gives it back much more slowly than the land. * UK less snow because the ocean gyre picks up the heat and moves to UK and it’s also because UK rains a lot karena the hot air creates moisture and boom rain General Circulation Model - Meridional flow - flowing in the north - south direction - El nino - currents comes up but it doesn't have enough energy to cross the pacific but instead it stays in areas like mexico and south america; moisture is stuck up there and continuous rain happens; very rare - La nina - the opposite; dry season in south america - Jet streams - river of fast moving air; not connected to the earth in any way; ( A LEVELS ) Atmospheric moisture and the processes related to it - Dew point - the tempo at which air cools enough so that the water vapour will condense to form liquid water; we can only see it when clouds form - Latent heat transfer Evaporation  - Natures way of trying to balance the percentages of water located on either land, sea or air - 3 main factors affecting evaporation : 1) Initial humidity - if it’s humid the air is basically “full” meaning that the air can’t evaporate anymore water 2) Supply of heat - heat will not determine whether evaporation occurs or not - only increases the amount of evaporation that may occur 3) Wind strength - air doesn’t move much can get saturated much quicker than air that is constantly moving/ being replaced by new air Condensation - Depends on saturation; two different processes can occur that can make this happen : 1) So much evaporation → air fills up with water vapour and it can’t hold it anymore 2) A temp drop occurs in the air; water molecules are forced close together to the point that we can see them; warm air can hold more water Human impact - Global warming = greenhouses are good; too much not good - Climate change and global warming are both normal and natural events; the problem is whether humans are speeding up these processes and making them worse = enhanced greenhouse effect URBAN CLIMATE 29/10/24 - City climates differ due to 3 factors that makes them different 1) Increased industry 2) Vehicle, glass, concrete, pavement 3) Density of everything - Overlooked factor : surface area - Smog traps the heat that is trying to escape → increase in temperature - Urban areas generally lack high moisture levels due to : 1) Low vegetation levels - vegetation is a good storage for moisture (the roots) 2) Dense drainage density - cities are specifically designed to remove water as quickly as possible → less surface moisture to evaporate the heat way - Decreased air flows caused by buildings allow heat to build up rather than it being blown away by the wind → greater instability (allow heat increase in an  area, creates low pressure) and thus greater likelihood of things like thunderstorms - Lightning is insanely hot → the air expands cause of the temperature RAIN 30/10/24 3 main types of rainfall : 1) Convectional - most common type of rainfall because all it requires is the rising of air (low pressure) by getting the air to be warmer than the air around it - if there’s water vapour, it will condense - forms cloud - rains (why is convectional rainfall the most common rain type?) - quiz question 2) Frontal - needs warm front(different air masses) and cold front to come together - warm will be forced to go above the cold air (cold air will just continue to move in a straight way) alias it will rise because it's less dense - if there’s water vapour/moisture in the warm front it will condense, form a cloud and will rain 3) Relief/topographic - what’s happening on the surface of the earth (rising,falling..); air rises from the ocean ( water vapour), cools, condensed, forms clouds → rain - Windward -where the moisture falls - Leeward - where the area is dry - Rainshadow effect - one side of the mountain (windward) receives more rainfall than the other side (leeward) because of the wind ROCKS AND WEATHERING The structure of the planet : 1) Inner core - insanely hot; it should be liquid but the massive amount of pressure keeps it in a solid state; so much force pressing on it on the outside  2) Outer core - sort of liquid; the materials that is made up careless dense and there is slightly less pressure - allows it to stay in a molten/liquid state 3) The mantle - what makes us most of our planet; technically it’s a liquid because it can move, but magma (what most of the mantle is made up of) located on different parts of the planet can be very different from each other - The outer layer is the crust; it’s completely solid because it;s the furthest from the core - its colder jad it solidifies - Lithosphere = combination of the crust and the upper mantle Plate Tectonics - how the solid crust essentially “rides” on top of the liquified mantle below it and the “currents” in the mantle cause the crust above it to move; movements: plate tectonics - oceanic and continental plates - what’s making the plates move? → hadley cells; warm air rising then cooling and dropping down back again. It’s the same exact process but it’s not in the atmosphere but in the below us in the magma; movement of the magma below the crust that “pushes” it along Plate Boundaries 1) When two plates are moving towards each other → convergent boundary (destructive boundary), they are called this because the process of coming together will cause the destruction of at least one of the plates (oceanic plate) - Area of destruction and a volcano builder (stratovolcanoes); violent and loud ones → benioff zone (crust bin); benioff zone is located under the continental plate  - - REASONS FOR VIOLENT VOLCANOES : Material from the benioff zone rises up – this is the dangerous stuff because as it hits the crust; the material and the pressure builds up below the surface and will lead to a formation of violent volcanoes - Usually one plate is heavier than the other; the heavier/denser plate will subduct where the plates meet - The borders of both plates will be forced downward → trench - The oceanic plate will continue moving down into the mantle where it will be destroyed by the heat and pressure - Plate breaking up – cause earthquakes 2) When plates move away from each other → divergent boundary (constructive boundary) as this movement will lead to the building of a new plate 3) conservative boundary → sliding past each other Theories on plate tectonitcs 1) Convection : - Friction between the moving magma below and crust above will cause the crust to move with the mantle  - It explains both divergent and convergent boundaries - It pulls the plate in the direction of the movement of the moving magma 2) Dragging : - The cooler and the denser end of the plate will pull or drag the lighter (because it hasn't been saturated by the water yet makanya masih light) end of the plate → movement of the surface - Karena the other end berat jadinya the plate like move downwards or falls and it basically pulls the other end of the plate Hot Spots (hawaii) - Area of a surface sitting on top a plume of lava and it can get through the crust creating volcanoes - The core of the earth is insanely hot… - No plate boundaries - Basically a proof that plates actually move - The volcano/plume stays in the same spot - the crust continues to move over it - Builder of shield volcanoes - Because the plates are moving, jadi kalo ada hot spots (volcanoes) are formed, it will move away with the movement of the moving plates; simultaneously, a new hot spot (volcano) is being formed at the “starting” place - The volcanoes makin jauh makin kecil karena erosion Sea floor spreading  - Ocean ridges → underwater mountain ranges formed by seafloor spreading (two plates that move away from each other and the magma naik, solidify and boom seafloor spreading); they are called ridges because they are the highest part - Ridges will flatten out as they move away from the initial ridge area due to pressure from the water above; newly formed ridges trap air when cooling which all that get squeezed out by the huge pressure; jadi plate nya makin menipis karena the water pressure is squeezing the air out and it gets replaced by water - Due to the cold temp and pressure form the above → the magma coming to the surface is slow moving and in small amounts actually ever reach the surface - The actual movement is because magma coming up and pushing away the plates Trenches - Accretion (uppermost layer of the oceanic plate that has been scrapped off; basically the material) build up due to the scraping of the top of the subducting plate steeper slope on the continental side - Where the two plates meet, the “v” point - Fold Mountains  1) Two plates coming each that have a similar density and it collides, gak ada yang subducting and boom folded mountains → tectonic uplift 2) The plate has ran into the oceanic plate but the others are still moving forward and piling up Volcanic Arc Islands - The benioff zone leads the pressure build up, magma rises and it breaks off the plate and reaches the surface Rocks Three main types : 1) Chemical 2) Mechanical (physical) 3) Biological (physical) Weathering : - Weathering is the breaking down of larger rocks into smaller ones and can even change the chemical makeup of some types of rock - Results of weathering cannot be reversed - Allows for easier erosion of materials; weathering makes things smaller therefore, they are easier for water and wind to move them - Has the ability to create new landforms by allowing for both the removal and the deposition of materials from different locations Physical/mechanical weathering : 1) Freeze - thaw → process when liquid freezes, it expands and then it goes back to liquid; the freezing puts pressure on the rocks (type of weathering); it can occur in different speeds depending on the location; most physical weathering will occur on the surface of the rock - 2) Salt crystallisation → salt will expand under the right conditions so if salt can get into a crack somewhere in a rock and then expand then the crack will get bigger and bigger; salt is very common and can be found anywhere so this process can occur almost everywhere even if we are in a location with no salt (SUPER uncommon), water has the ability to transport salt into that area 3) Heating and cooling → when things get hot they expand, when things get cool they contract; this repeated action will eventually cause cracks at the surface; can be quick (daily) or slower (seasonality); rock is very dense so the largest change in heat is at the surface – the greatest cracking happens at the surface causing it to peel away (exfoliation) 4) Pressure release → also creates another form of exfoliation-dilatation; the result is still the same but the process is different; outermost layer experiences the most pressure → outermost layer that will expand and contract the most; pseudo bedding planes (different layers of rock); more surface area = more surface expansion and contraction; di luar nya ada less pressure causing to have more expansion  Chemical Weathering - WATER! - It’s most effective below the surface : 1) Water travelling through the soil can absorb mild acids → making the water better able to breakdown certain types of rock; it can change the ph level of the soil 2) Temperatures below the surface are more stable (less exposed to the sun); chemical reactions don’t really like large temp variations, specifically, consistent warm temperature - 3 main types of chemical weathering : 1) Carbonation - solution - When water mixes with enough dissolved carbon dioxide it forms a weak acid (carbonic acid), sedimentary rocks or those containing calcium carbonate like limestone can be broken down by acid, WEAK acid → doesn’t really affect all rocks but it does effect certain rocks more than others especially limestone 2) Hydrolysis : - Molecules in the water are used to break apart the chemical structures of different materials; usually only affecting sedimentary rocks - When water is used to break stuff down - It removes certain parts of the rocks, leaving behind a chemically different rock mass 3) Hydration : - Minerals in rock will absorb water and expand → creating a change in the rock structure Factors that control the type and rate of weathering climate : - Impossible to calculate the exact measure of amount and type of weathering because there is too many different possible combinations but it’s easy to make general observation :  1) Physical weather increases when temperature variations increases; the speed within which these variations “cycle” is a huge influence 2) Increase in heat and water → increase chemical weathering Rock type - Chemical composition → all chemicals are different and react differently to outside influences like heat and moisture - Cements in sedimentary rock are different depending on rock type; some cements are clay, silica, calcite, they all have different strengths - Joints and bedding planes depend on two things only → how many and how big; jointing is just the combinations of vertical and horizontal bends JOINTS - - Rock structure → include factors such as joints/bedding planes; grain size (smaller grains will fit together better making them harder to break apart); it all comes down to the specific materials making up the rock mass some particles are simply stronger than others Vegetation - Roots - physical - Acidity - chemical - Soil can influence weathering; healthy soil will increase the vegetation and therefore increases the processes - Infertile soil will NOT attract vegetation - protecting the rocks found within from the same processes Relief (Slopes) - Weathering can slow down if the already weathered material isn’t removed → semisalnya if we think of flat surfaces they tend to weather  more slowly karena lebih susah to remove the previously weathered material; flat surfaces don’t weather very quickly - If the slope is too steep, water could pass over the material too quickly without absorbing into the materials to weather it - That’s why slopes that aren’t too steep or shallow often weather faster - Aspect (possibly in the sem exam) - direction that a slope is facing - Valley’s have two sides, facing each other so valleys have two sides that are facing in opposite directions. Jadi on the day time the south facing slope will experience more sunlight causing to experience more PHYSICAL WEATHERING karena there is more change in temperature (it rises) ; kalo north it receives less sunlight jadi there’s not much changes in temp alias temperature nya lebih stable so it will be experience more CHEMICAL WEATHERING → THIS IS FOR NORTHERN HEMISPHERE Slope Processes - Basically just an unflat surface - Can be underwater or on dry land - Can be created by the buildup of eroded materials or created by removing material from an existing surface - Climate - a huge part in the formation and processes found within a slope - water availability – misalnya if we add a little water on to a slope, the dirt will stay and won’t fly away because of the wind just like how if there is no water on the slope, the dirt can fly away due to the wind (IT’S IN THE SEM EXAM) - Geological structures : fault lines, volcanic activity, rock type - Soil is a HUGE variable in slope processes; different soils act very differently. Soil is brown because RUSTING (the iron gets oxidised). Larger particles are harder to be eroded in wind and rain. SOIL AGGREGATES - lump of soil; water will hold soil together - if too much then it will flow away - Aspects - Vegetation