Unit 4: Earth Systems and Resources
Plate Tectonics: Theory explaining the movement of the Earth’s rigid lithospheric plates is the result of convection processes in the underlying partially molten mantle
Earth’s Structure
Core: Dense mass of solid nickel, iron, and radioactive elements that release heat
Mantle: liquid layer of magma surrounding the core, kept liquefied by intense heat from core
Asthenosphere: solid, flexible layer of mantle, beneath the lithosphere
Lithosphere: thin, brittle layer of rock floating on top of mantle ( broken up into tectonic plates
Crust: very outer layer of the lithosphere, Earth’s surface
Plate Boundaries
Divergent Plate Boundary: Plates move away from each other
Rising magma plume from mantle forces plates apart
Forms: mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys (on land)
Convergent Plate Boundary:Plates move towards each other
Leads to subduction (one plate being forced beneath another)
Forms: mountains, island arcs, earthquakes, and volcanoes
Transform fault Plate Boundary: plates slide past each other in opposite directions
Forms: earthquakes (occurs when the stress on lithospheric plates overcomes a locked fault, resulting in a release of energy)
Convection Cycles (Divergent): Magma heated by earth’s core rises towards lithosphere
Rising magma cools & expands, forcing oceanic plates apart
Creates, mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”
Magma cools, and solidifies into new lithosphere
Magma heated by earth’s core rises towards lithosphere
Rising magma cools & expands, forcing oceanic plates apart
Creates, mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”
Magma cools, and solidifies into new lithosphere
Convergent Boundary - Subduction Zone
Oceanic-Oceanic : one plate subducts underneath other
Forces magma up to lithosphere surface, forming mid ocean volcanoes
Island arcs
Off-shore trench
Oceanic-Continental : dense oceanic plate subducts beneath cont. Plate & melts back into magma
Forces magma up to lithosphere surface
Coastal Mountains (Andes), Volcanoes on land, trenches, tsunamis
Continental-Continental one plate subducts underneath other, forcing surface crust upward (mountains)
Ex: Himalayas
Transform Fault Boundary
Plates sliding past each other in opp. directions creates a fault (fracture in rock surface)
Earthquakes = most common activity
Occurs when rough edges of plates get stuck on each other
Pressure builds as plates keep sliding, but edges stay stuck
When stress overcomes the locked fault, plates suddenly release, slide past each other and release energy that shakes the lithosphere
Ring of Fire: pattern of volcanoes all around pacific plate
Offshore island arcs (Japan)
Transform faults: likely location of earthquakes
Hotspots: areas of esp. hot magma rising up to lithosphere
Mid-ocean Islands (iceland, Hawaii)
4.2 Soil Formation & Erosion
Weathering: Breakdown of rocks into smaller pieces
Physical (wind, rain, freezing/thawing of ice)
Biological (roots of trees crack rocks)
Chemical (acid rain, acids from moss/lichen)
Weathering of rocks = soil formation
Broken into smaller and smaller pieces
Carried away and deposited by erosion
Erosion
Transport of weathered rock fragments by wind and rain
Carried to new location and deposited (deposition)
Soil Formation:
Weathering of parent material produces smaller, and smaller fragments that make up geological/inorganic part of soil
Sand, silt, clay
Minerals
From above
Breakdown of organic matter adds humus to soil
Erosion deposits soil particles from other areas, adding to soil
Soil Horizons
O-Horizon: layer of organic matter (plant roots, dead leaves, animal waste, etc) on top of soil
Provides nutrients and limits H2O loss to evap.
A-Horizon: aka topsoil; layer of humus (decomposed organic matter) and minerals from parent material
A-Horizon has most biological activity (earthworms, soil microbes) breaking down organic matter to release nutrients
B-Horizon: aka subsoil; lighter layer below topsoil, mostly made of minerals w/little to no org. matter
Contains some nutrients
C-Horizon: least weathered soil that is closest to the parent material, sometimes called bedrock
Loss of Topsoil: tiling (turning soil for ag.) + loss of vegetation disturb soil and make it more easily eroded by wind and rain
Loss of top soil dries out soil, removes nutrients + soil organisms that recycle nutrients
Compaction: compression of soil by machines (tractors, bulldozers, etc.), grazing livestock, and humans reduces ability to hold moisture
Dry soil erodes more easily
Dry soil supports less plant growth, less root structure, leading to more erosion
Nutrient Depletion: repeatedly growing crops on the same soil removes key nutrients (N, P, K, Na, Mg) over time
Reduces ability to grow future crops
Minimizing erosion of topsoil into surface water:
maintain/plant vegetated buffers between surface waters and crop fields (creates habitats to maintain biodiversity)
Create retention ponds to capture eroded soil (recharges groundwater by slowing flow of runoff and allowing infiltration, maintains biodiversity)
Maintain cover crops on fields after harvests (provides nutrients to next crop)
Use no-till agriculture (reduces fuel requirements, reduces releases of greenhouse gases associated w mechanized agriculture>decreases global climate change)
Soil helps filter and clean water that moves through them
Soil Erosion into bodies of water can create turbidity, reduce the penetration of sunlight (reducing photosynthesis), and clog the gills of aquatic organisms
4.3 Soil Composition & Properties
Soil Particle Size, Texture, and Porosity
Geologic (rock) portion of soil is made up of 3 particles
(biggest to smallest) Sand > silt > clay
Soil Texture: is the % of sand, silt, and clay in a soil
Always adds up to 100% ex: 40-40-20
B/c sand is bigger, it has bigger pores (empty spaces between particles)
This allows air + water to enter sandy soil easily
Clay has smallest pores, so it’s harder for air + water to enter clay-heavy soils
Porosity is the amount of pore space a soil has
more sand in a soil = more porous/higher porosity (easier for water + air to enter)
more clay in a soil = less porous/less porosity (harder for water + air to enter)
Water
Needs to hold water, but not too much
Factors that increase H2O holding cap.
Aerated soil (biological activity)
Compost/humus/organic matter
Clay content
Root structure, especially natives
Factors that decrease H2O holding cap.
Compacted soil (machines, cows)
Topsoil erosion
Sand
Root loss
Nutrients
N, P, K+, Mg2+, Ca+, Na+
Factors that increase soil nutrients
Organic matter (releases nutrients)
Humus (holds and releases nutrients)
Decomposer activity (recycles nut.)
Clay (neg. charge binds pos. nutrients)
Bases (Calcium carbonate - limestone)
Factors that decrease soil nutrients
Acids leach pos. charge nutrients
Excessive rain/irr. leeches nutrients
Excessive farming depletes nut.
Topsoil erosion
Effect on Soil Fertility
Soil that is too sandy (too permeable) drains water too quickly for roots + dries out
Clay-heavy soil doesn’t let H2O drain to roots, or waterlogs (suffocating them)
Ideal soil for most plant growth is loam, which balances porosity or drainage, with H2O holding cap. (40% sand; 40% silt; 20% clay)
4.4 Atmosphere
Nitrogen 78% Mostly in the form of N2 (unuseable to plants without being fixed)
Argon ~ 0.93%: Inert, noble gas
Oxygen ~ 21%: Produced by photosynthesis in plants & needed for human/animal respiration
Water Vapor ~ 0-4%: Varies by region & conditions; acts as a temporary GHG, but less concerning than CO2
CO2 ~ 0.04%: Most important GHG; leads to global warming
Removed from atm. by photosynthesis
Exosphere: Outermost layer where atm. merges with space
Thermosphere: Therm = hottest temp;
absorbs harmful X-rays & UV radiation
charged gas molecules glow under intense solar radiation northern lights (aurora borealis)
Mesosphere: Meso = for middle; 60-80 km, even less dense
Stratosphere: “S” for second - 16-60 km; less dense due to less pressure from layers above
Thickest ozone/O3 layer is found here; absorbs UV-B & UV-C rays which can mutate DNA of animals (cancer)
Troposphere: Tropo = change (weather occurs here) - 0-16 km, most dense due to pressure of other layers above it
Most of atmosphere’s gas molecules are found here
Ozone (O3) in the troposphere is harmful to humans (respiratory irritant) & damages plant stomata, and forms smog
Layers of earth’s atm. are based on where temp. gradients change with distance from earth’s surface
Thermosphere: temp. Increases due to absorption of highly energetic solar radiation
Hottest place on earth (3,100oF)
Mesosphere: temp. decreases because density decreases, leaving fewer molecules to absorb sun
Coldest place on earth (-150oF)
Stratosphere: temp. increases because top layer of stratosphere is warmed by UV rays (like pool surface)
Troposphere: temp. decreases as air gets further from warmth of earth’s surface (temp drops with altitude)
4.5 Global Wind Patterns
4 Properties that determine how air moves
Density: less dense air rises and more dense air sinks
Warm air is LESS (more likely to rise) dense than cool air
As warm air rises from the equator, it condenses and spreads out due to rotation of the earth (A Hadley Cell) (Hadley happens where its hot)
The precipitation from the condensation falls between 0 and 30 N/S latitude creating tropical rainforest
At 30 N/S, the dryer air sinks back down to the surface= deserts
Water Vapor Capacity: how much water vapor can air hold?
Warm air can hold more water vapor
Saturation point: max amount of water vapor air can hold
Temp goes up, saturation point goes up; temp goes down, saturation point goes down
Pressure: as air rises, pressure decreases
Increase in attitude, decrease in pressure, volume increases, temp drops = adiabatic cooling
Pressure and volume inversely proportional
Altitude increases, pressure increases, volume decreases, temp increases = Adiabatic heating
Latent Heat Release: water vapor in the air condenses to form precipitation, to warm up air
Coriolis Effect:
Deflection of objects traveling through the atmosphere due to the spin of earth
Objects are deflected to the RIGHT in the northern hemisphere and to the LEFT in the southern
The spinning of cyclonic storms (counterclockwise in the northern hemisphere and clockwise in the southern)=result of the coriolis effect
Air at 30 degrees moves back to L pressure of equator
West between 0-30 degrees moves from E>W
Because Earth spinning from W>E
Wind between 30-60 movies W>E
Earth spins faster @ 30 degrees than 60
Throw ball from northern hemisphere(moving slower) > equator it moves to the right
Global Wind Patterns
Air moves out from 30 - 0 and 60 due to high pressure @ 30 and low pressure @ 0 and 60
Air rising @ equator = low pressure
Air sinking down at 30 = high pressure
0-30 winds blow E>W (EASTERN TRADE)
Drives ocean current clockwise in N hemisphere, counterclockwise in S hemisphere
30-60 winds blow W>E (WESTERLIES
Drives weather patterns of N America
4.7 Solar Radiation & Earth’s Seasons
isolation : the amount of solar radiation ( energy from sun’s rays) reaching an area
Solar Intensity & Latitude:
Depends on
Angle: how directly rays strike Earth’s surface
The amount of atmosphere sun’s rays pass through
Equator = higher isolation than higher latitudes
At high latitudes, sunlight must pass through more atmosphere & loses more of its energy
A given amount of solar energy is spread over a larger surface areas than at the equator
Solar Intensity & Season
Orbit of earth around sun + tilt on axis changes angle of sun’s rays
Causes varying insolation, varying length of days, and seasons
Tilt of earth’s axis stays fixed during orbit
June/December solstices: N or S hemisphere is maximally tilted toward sun ( summer/winter(
March/Sept equinox: N and S hemispheres equally facing sun
Albedo
The proportion of light that is reflected by a surface
Surfaces with higher albedo reflect more light, and absorb less ( ice/snow)
Absorb less heat
Surfaces with low albedo reflect less light, and absorb more (water)
Absorb more heat
Positive feedback loop>>>
Albedo & Surface Temperature
When sunlight is absorbed by a surface, it gives off infrared radiation (heat)
Areas with lower albedo, absorb more sunlight light/hear
Urban Heat Island: urban areas are hotter than surrounding rural areas due to low albedo blacktop
Polar regions are colder due to high albedo
4.8 Earth’s Geography & Climate
Climate & Geography
Climate is determined by insolation ( latitude>angle of insolation & atmosphere
Higher latitudes receive less insolation ( cooler, less precipitation)
Equator receives most intense insolation ( higher temp, air rises, high precip)
Thermal inversion: cooler air at the surface becomes “trapped” by a later of warmer air above it
Increases intensity of surface air pollution
mountains : disrupt wind, and produce rain shadow effect
Oceans: moderate temp & add moisture to the air
Rain Shadow
A drier area of land next to a higher elevation, higher elevation (such as mtn.) blocks the precipitation from reaching the area
Warm, moist air from ocean hits “windward” side of mts, rises, cools> lush, green vegetation
dry air descends down “leeward” side of mtn, warming as it sinks
Leads to arid dry desert conditions
4.9 El Niño & La Nina
El Nino (southern oscillation- ENSO) is a periodic, non-anthropogenic phenomenon that occurs in the southern pacficic ocean
Changes to patterns of rainfall, wind, ocean circulation occur that can cause climatic/environmental/economic disruptions
Effects: Suppressed upwelling and less productive fisheries in SA; warmer winter in much of N America; decreased hurricane activity in atlantic ocean, increased precip/flooding in americas ( w coast esp)
Effects of LA NINA: stronger upwelling and better fisheries in SA than normal; worse tornado activity in US & hurricane activity in atlantic; rainier/warmer/increased monsoons in SE Asia
Global Ocean Surface Currents
Gyers: large ocean circ. Patterns due to global warming
Clockwise in N hemisphere, counterclockwise in S hemisphere
E>W trade winds between 0-30 push eq. Current E >W
Westerlies between 30-60 degrees and pushes mid lat. currents W>E
Upwelling zones: areas of ocean where winds blow warm surface water away from a land mass, drawing colder/deeper water to replace it
Brings O2 + nutrients to surface = productive fishing
Thermohaline Circulation
Connects all of world’s oceans, mixing salt, nutrients, and temp throughout
War, water from Gulf of MX moves toward North Pole
Cools & Evaporates as it moves towards poles
saltier/colder @ poles , is more dense making it sink
Spreads along ocean floor
Rises back up into shallow warm ocean current @ upwelling zones
Plate Tectonics: Theory explaining the movement of the Earth’s rigid lithospheric plates is the result of convection processes in the underlying partially molten mantle
Earth’s Structure
Core: Dense mass of solid nickel, iron, and radioactive elements that release heat
Mantle: liquid layer of magma surrounding the core, kept liquefied by intense heat from core
Asthenosphere: solid, flexible layer of mantle, beneath the lithosphere
Lithosphere: thin, brittle layer of rock floating on top of mantle ( broken up into tectonic plates
Crust: very outer layer of the lithosphere, Earth’s surface
Plate Boundaries
Divergent Plate Boundary: Plates move away from each other
Rising magma plume from mantle forces plates apart
Forms: mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys (on land)
Convergent Plate Boundary:Plates move towards each other
Leads to subduction (one plate being forced beneath another)
Forms: mountains, island arcs, earthquakes, and volcanoes
Transform fault Plate Boundary: plates slide past each other in opposite directions
Forms: earthquakes (occurs when the stress on lithospheric plates overcomes a locked fault, resulting in a release of energy)
Convection Cycles (Divergent): Magma heated by earth’s core rises towards lithosphere
Rising magma cools & expands, forcing oceanic plates apart
Creates, mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”
Magma cools, and solidifies into new lithosphere
Magma heated by earth’s core rises towards lithosphere
Rising magma cools & expands, forcing oceanic plates apart
Creates, mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”
Magma cools, and solidifies into new lithosphere
Convergent Boundary - Subduction Zone
Oceanic-Oceanic : one plate subducts underneath other
Forces magma up to lithosphere surface, forming mid ocean volcanoes
Island arcs
Off-shore trench
Oceanic-Continental : dense oceanic plate subducts beneath cont. Plate & melts back into magma
Forces magma up to lithosphere surface
Coastal Mountains (Andes), Volcanoes on land, trenches, tsunamis
Continental-Continental one plate subducts underneath other, forcing surface crust upward (mountains)
Ex: Himalayas
Transform Fault Boundary
Plates sliding past each other in opp. directions creates a fault (fracture in rock surface)
Earthquakes = most common activity
Occurs when rough edges of plates get stuck on each other
Pressure builds as plates keep sliding, but edges stay stuck
When stress overcomes the locked fault, plates suddenly release, slide past each other and release energy that shakes the lithosphere
Ring of Fire: pattern of volcanoes all around pacific plate
Offshore island arcs (Japan)
Transform faults: likely location of earthquakes
Hotspots: areas of esp. hot magma rising up to lithosphere
Mid-ocean Islands (iceland, Hawaii)
4.2 Soil Formation & Erosion
Weathering: Breakdown of rocks into smaller pieces
Physical (wind, rain, freezing/thawing of ice)
Biological (roots of trees crack rocks)
Chemical (acid rain, acids from moss/lichen)
Weathering of rocks = soil formation
Broken into smaller and smaller pieces
Carried away and deposited by erosion
Erosion
Transport of weathered rock fragments by wind and rain
Carried to new location and deposited (deposition)
Soil Formation:
Weathering of parent material produces smaller, and smaller fragments that make up geological/inorganic part of soil
Sand, silt, clay
Minerals
From above
Breakdown of organic matter adds humus to soil
Erosion deposits soil particles from other areas, adding to soil
Soil Horizons
O-Horizon: layer of organic matter (plant roots, dead leaves, animal waste, etc) on top of soil
Provides nutrients and limits H2O loss to evap.
A-Horizon: aka topsoil; layer of humus (decomposed organic matter) and minerals from parent material
A-Horizon has most biological activity (earthworms, soil microbes) breaking down organic matter to release nutrients
B-Horizon: aka subsoil; lighter layer below topsoil, mostly made of minerals w/little to no org. matter
Contains some nutrients
C-Horizon: least weathered soil that is closest to the parent material, sometimes called bedrock
Loss of Topsoil: tiling (turning soil for ag.) + loss of vegetation disturb soil and make it more easily eroded by wind and rain
Loss of top soil dries out soil, removes nutrients + soil organisms that recycle nutrients
Compaction: compression of soil by machines (tractors, bulldozers, etc.), grazing livestock, and humans reduces ability to hold moisture
Dry soil erodes more easily
Dry soil supports less plant growth, less root structure, leading to more erosion
Nutrient Depletion: repeatedly growing crops on the same soil removes key nutrients (N, P, K, Na, Mg) over time
Reduces ability to grow future crops
Minimizing erosion of topsoil into surface water:
maintain/plant vegetated buffers between surface waters and crop fields (creates habitats to maintain biodiversity)
Create retention ponds to capture eroded soil (recharges groundwater by slowing flow of runoff and allowing infiltration, maintains biodiversity)
Maintain cover crops on fields after harvests (provides nutrients to next crop)
Use no-till agriculture (reduces fuel requirements, reduces releases of greenhouse gases associated w mechanized agriculture>decreases global climate change)
Soil helps filter and clean water that moves through them
Soil Erosion into bodies of water can create turbidity, reduce the penetration of sunlight (reducing photosynthesis), and clog the gills of aquatic organisms
4.3 Soil Composition & Properties
Soil Particle Size, Texture, and Porosity
Geologic (rock) portion of soil is made up of 3 particles
(biggest to smallest) Sand > silt > clay
Soil Texture: is the % of sand, silt, and clay in a soil
Always adds up to 100% ex: 40-40-20
B/c sand is bigger, it has bigger pores (empty spaces between particles)
This allows air + water to enter sandy soil easily
Clay has smallest pores, so it’s harder for air + water to enter clay-heavy soils
Porosity is the amount of pore space a soil has
more sand in a soil = more porous/higher porosity (easier for water + air to enter)
more clay in a soil = less porous/less porosity (harder for water + air to enter)
Water
Needs to hold water, but not too much
Factors that increase H2O holding cap.
Aerated soil (biological activity)
Compost/humus/organic matter
Clay content
Root structure, especially natives
Factors that decrease H2O holding cap.
Compacted soil (machines, cows)
Topsoil erosion
Sand
Root loss
Nutrients
N, P, K+, Mg2+, Ca+, Na+
Factors that increase soil nutrients
Organic matter (releases nutrients)
Humus (holds and releases nutrients)
Decomposer activity (recycles nut.)
Clay (neg. charge binds pos. nutrients)
Bases (Calcium carbonate - limestone)
Factors that decrease soil nutrients
Acids leach pos. charge nutrients
Excessive rain/irr. leeches nutrients
Excessive farming depletes nut.
Topsoil erosion
Effect on Soil Fertility
Soil that is too sandy (too permeable) drains water too quickly for roots + dries out
Clay-heavy soil doesn’t let H2O drain to roots, or waterlogs (suffocating them)
Ideal soil for most plant growth is loam, which balances porosity or drainage, with H2O holding cap. (40% sand; 40% silt; 20% clay)
4.4 Atmosphere
Nitrogen 78% Mostly in the form of N2 (unuseable to plants without being fixed)
Argon ~ 0.93%: Inert, noble gas
Oxygen ~ 21%: Produced by photosynthesis in plants & needed for human/animal respiration
Water Vapor ~ 0-4%: Varies by region & conditions; acts as a temporary GHG, but less concerning than CO2
CO2 ~ 0.04%: Most important GHG; leads to global warming
Removed from atm. by photosynthesis
Exosphere: Outermost layer where atm. merges with space
Thermosphere: Therm = hottest temp;
absorbs harmful X-rays & UV radiation
charged gas molecules glow under intense solar radiation northern lights (aurora borealis)
Mesosphere: Meso = for middle; 60-80 km, even less dense
Stratosphere: “S” for second - 16-60 km; less dense due to less pressure from layers above
Thickest ozone/O3 layer is found here; absorbs UV-B & UV-C rays which can mutate DNA of animals (cancer)
Troposphere: Tropo = change (weather occurs here) - 0-16 km, most dense due to pressure of other layers above it
Most of atmosphere’s gas molecules are found here
Ozone (O3) in the troposphere is harmful to humans (respiratory irritant) & damages plant stomata, and forms smog
Layers of earth’s atm. are based on where temp. gradients change with distance from earth’s surface
Thermosphere: temp. Increases due to absorption of highly energetic solar radiation
Hottest place on earth (3,100oF)
Mesosphere: temp. decreases because density decreases, leaving fewer molecules to absorb sun
Coldest place on earth (-150oF)
Stratosphere: temp. increases because top layer of stratosphere is warmed by UV rays (like pool surface)
Troposphere: temp. decreases as air gets further from warmth of earth’s surface (temp drops with altitude)
4.5 Global Wind Patterns
4 Properties that determine how air moves
Density: less dense air rises and more dense air sinks
Warm air is LESS (more likely to rise) dense than cool air
As warm air rises from the equator, it condenses and spreads out due to rotation of the earth (A Hadley Cell) (Hadley happens where its hot)
The precipitation from the condensation falls between 0 and 30 N/S latitude creating tropical rainforest
At 30 N/S, the dryer air sinks back down to the surface= deserts
Water Vapor Capacity: how much water vapor can air hold?
Warm air can hold more water vapor
Saturation point: max amount of water vapor air can hold
Temp goes up, saturation point goes up; temp goes down, saturation point goes down
Pressure: as air rises, pressure decreases
Increase in attitude, decrease in pressure, volume increases, temp drops = adiabatic cooling
Pressure and volume inversely proportional
Altitude increases, pressure increases, volume decreases, temp increases = Adiabatic heating
Latent Heat Release: water vapor in the air condenses to form precipitation, to warm up air
Coriolis Effect:
Deflection of objects traveling through the atmosphere due to the spin of earth
Objects are deflected to the RIGHT in the northern hemisphere and to the LEFT in the southern
The spinning of cyclonic storms (counterclockwise in the northern hemisphere and clockwise in the southern)=result of the coriolis effect
Air at 30 degrees moves back to L pressure of equator
West between 0-30 degrees moves from E>W
Because Earth spinning from W>E
Wind between 30-60 movies W>E
Earth spins faster @ 30 degrees than 60
Throw ball from northern hemisphere(moving slower) > equator it moves to the right
Global Wind Patterns
Air moves out from 30 - 0 and 60 due to high pressure @ 30 and low pressure @ 0 and 60
Air rising @ equator = low pressure
Air sinking down at 30 = high pressure
0-30 winds blow E>W (EASTERN TRADE)
Drives ocean current clockwise in N hemisphere, counterclockwise in S hemisphere
30-60 winds blow W>E (WESTERLIES
Drives weather patterns of N America
4.7 Solar Radiation & Earth’s Seasons
isolation : the amount of solar radiation ( energy from sun’s rays) reaching an area
Solar Intensity & Latitude:
Depends on
Angle: how directly rays strike Earth’s surface
The amount of atmosphere sun’s rays pass through
Equator = higher isolation than higher latitudes
At high latitudes, sunlight must pass through more atmosphere & loses more of its energy
A given amount of solar energy is spread over a larger surface areas than at the equator
Solar Intensity & Season
Orbit of earth around sun + tilt on axis changes angle of sun’s rays
Causes varying insolation, varying length of days, and seasons
Tilt of earth’s axis stays fixed during orbit
June/December solstices: N or S hemisphere is maximally tilted toward sun ( summer/winter(
March/Sept equinox: N and S hemispheres equally facing sun
Albedo
The proportion of light that is reflected by a surface
Surfaces with higher albedo reflect more light, and absorb less ( ice/snow)
Absorb less heat
Surfaces with low albedo reflect less light, and absorb more (water)
Absorb more heat
Positive feedback loop>>>
Albedo & Surface Temperature
When sunlight is absorbed by a surface, it gives off infrared radiation (heat)
Areas with lower albedo, absorb more sunlight light/hear
Urban Heat Island: urban areas are hotter than surrounding rural areas due to low albedo blacktop
Polar regions are colder due to high albedo
4.8 Earth’s Geography & Climate
Climate & Geography
Climate is determined by insolation ( latitude>angle of insolation & atmosphere
Higher latitudes receive less insolation ( cooler, less precipitation)
Equator receives most intense insolation ( higher temp, air rises, high precip)
Thermal inversion: cooler air at the surface becomes “trapped” by a later of warmer air above it
Increases intensity of surface air pollution
mountains : disrupt wind, and produce rain shadow effect
Oceans: moderate temp & add moisture to the air
Rain Shadow
A drier area of land next to a higher elevation, higher elevation (such as mtn.) blocks the precipitation from reaching the area
Warm, moist air from ocean hits “windward” side of mts, rises, cools> lush, green vegetation
dry air descends down “leeward” side of mtn, warming as it sinks
Leads to arid dry desert conditions
4.9 El Niño & La Nina
El Nino (southern oscillation- ENSO) is a periodic, non-anthropogenic phenomenon that occurs in the southern pacficic ocean
Changes to patterns of rainfall, wind, ocean circulation occur that can cause climatic/environmental/economic disruptions
Effects: Suppressed upwelling and less productive fisheries in SA; warmer winter in much of N America; decreased hurricane activity in atlantic ocean, increased precip/flooding in americas ( w coast esp)
Effects of LA NINA: stronger upwelling and better fisheries in SA than normal; worse tornado activity in US & hurricane activity in atlantic; rainier/warmer/increased monsoons in SE Asia
Global Ocean Surface Currents
Gyers: large ocean circ. Patterns due to global warming
Clockwise in N hemisphere, counterclockwise in S hemisphere
E>W trade winds between 0-30 push eq. Current E >W
Westerlies between 30-60 degrees and pushes mid lat. currents W>E
Upwelling zones: areas of ocean where winds blow warm surface water away from a land mass, drawing colder/deeper water to replace it
Brings O2 + nutrients to surface = productive fishing
Thermohaline Circulation
Connects all of world’s oceans, mixing salt, nutrients, and temp throughout
War, water from Gulf of MX moves toward North Pole
Cools & Evaporates as it moves towards poles
saltier/colder @ poles , is more dense making it sink
Spreads along ocean floor
Rises back up into shallow warm ocean current @ upwelling zones