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APES REVIEW:EARTH SYSTEMS
AND GLOBAL CHANGES
Miss Hayungs
PROPERTIES THAT DRIVE GLOBAL PROCESSES Remember some key scientific
concepts:
The relationship between Temperature, Pressure, and Density (relates to convection)
Convection, Conduction, and Radiation (transfer of heat or heat energy)
These are all factors in remembering movement in the atmosphere, oceans, mantle, etc.
T P D As temperature increases, pressure
increases As temperature decreases, pressure
decreases As pressure increases, density decreases As pressure decreases, density increases
T P DT P D
The key is to remember how the molecules move in relation to the temperature and what that means for density
CONVECTION Energy is moved by energy-containing
particles from one place to another (primary in the atmosphere, oceans, and within Earth)
This is the circulation of material that occurs when the density of material is decreased due to warming or increased due to cooling. The movement of matter here forms a convection current due to the rising of less dense matter and sinking of the cooler matter.
CONVECTION Convection in the mantle is the mechanism
for plate movements. Convection in the atmosphere is responsible
for global winds (think back to Hadley, Ferrel and
Polar cells), formation of some clouds, high and low pressure systems, and ultimately for various climates and biomes.
Convection in the oceans helps to move cold and warm water currents around the globe and adds to pressure differences. (thermohaline
circulation involves differences in temp and salinity)Convection moves heat that comes from the
sun and distributes it around the globe.
CONDUCTION Energy transferred from one particle to
another through a collision between the two particles.
When this happens some heat is produced.
Example: The molecules in the pot of water heat up because the pot is touching the burner.
RADIATION Energy carried by a photon from one
place to another Radiation is energy that comes from a
source and travels through some material or through space. Light, heat and sound are types of radiation.
Ionizing radiation can produce ions in matter.
(Ex…the more damaging end of the EM spectrum)
PROPERTIES OF WATER Weather is affected by convection,
conduction and radiation, but also properties of water such as:
Specific heat (moderation of temperature fluctuations along coastal areas or near large bodies of water)
Energy of vaporization (evaporative cooling) (latent heat) (Ex. Evaporation of water – holds or stores a lot of energy for use in hurricane)
LITHOSPHERE – PLATE TECTONICS Theory of Continental Drift
Alfred Wegener proposed that all of the continents were once joined together (matching coastlines, fossil correlations)
This was rejected by the scientific community because he had no explanation for how/why the continents moved.
Seafloor SpreadingHarry Hess compiled data from several
scientists to explain his theory of seafloor spreading. (sonar used to map the topography, magnetic readings of rock, sediment data, isochron maps of seafloor)
PLATE TECTONICS Using all of the data compiled over the
decades from several scientists, the Theory of Plate Tectonics was developed.
Types of crust Continental and Oceanic
Plate Boundaries - Divergent boundariesConvergent boundariesTransform boundaries
BOUNDARIES Divergent
Plates move away from each other Oceanic-Oceanic divergence= new crust
formed at oceanic ridge Continental-Continental= new crust formed at
rift valleys Ex- Mid-Atlantic Ridge and African Rift
Convergent Plates move toward each other; oceanic plate
will subduct Continental-Continental convergence= no
subduction; plates will buckle – forms tall, folded mountains Ex. Himalayas
Divergent boundary of oceanic crust
Convergent boundary of oceanic
and continental crust
Oceanic-Oceanic=one plate subducts, forming a trench; the subducted plate will be melted/recycled; volcanic islands are formed Ex. Mariana trench and Japan
Oceanic-Continental=oceanic plate subducts, forming a trench at the subduction zone; volcanic mountain range forms on continent Peru-Chile trench and Andes Mountains
TransformPlates slide past each other.No new crust formed, no recycling of crust
Ex. San Andreas fault
Transform boundary
EARTHQUAKES Plate boundaries are seismically active
and prone to earthquakes. When the plates move, there is friction
between the plates, eventually the plates will “give”, and there is a release of kinetic energy.
Where the rocks “give” is the focus. Directly above the focus at the surface
is the epicenter. Seismic waves radiate outward from the
focus – three types…
SEISMIC WAVES Primary waves (P-waves)
CompressionMove through any material and arrive at
seism,ic station first Secondary waves (S-waves)
Lateral motionSlower than p-waves and only move
through solids Surface waves (L-waves)
Only sensed at surface
EARTHQUAKES Three seismic stations are needed to
triangulate where the focus occurred
The Richter ScaleLogarithmic scale that measures the
intensity of the earthquake. For every increase in whole number on the
Richter scale, there is a ten-fold increase in ground displacement and 30-fold increase in energy released. (Ex. 1960 Chile earthquake measured a 9.5!)
ROCK CYCLE The cycling of rock between three types of
material: Igneous rock – formed from cooling of magma
Intrusive/extrusive classification based on where it forms
Felsic/intermediate/mafic/ultramafic classification based on mineral composition of rock
Sedimentary rock – formed from weathering, erosion, deposition, burial, lithification Clastic/organic/chemical classification based on how it
forms Clastic sedimentary rock is further classified by grain
size Metamorphic rock – formed by exposure to heat
and pressure Foliated/non-foliated classification based on presence
of lines or lack of lines seen in rock (texture)
IGNEOUS ROCK
SOIL Soil forms from the weathering of rock.
It can take hundreds to thousands of years to create a deep soil.
Soil composition depends on the minerals in the parent rock. Nutrients come from these minerals and the organic material that will decompose and become part of the nutrient load.
Soil profiles (cross-section of horizons)Will vary by biome due to amount and type
of weathering as well as amount of precipitation
SOIL HORIZONS WITHIN A PROFILE
R horizon
Topsoil
Subsoil
Zone of eluviation and leaching
SOIL CONSERVATION Agricultural methods
No-till farming or low-till farmingTerracing or contour farmingTrees as wind breaks
Case Studies1930s Dust Bowl in the plains states
1935 Soil Conservation Act
HYDROSPHERE – THE OCEAN Ocean currents
Help to disperse heat from the sun around the globe
Ocean currents caused by: Wind (surface currents) Differences in salinity and temperature (density
currents or deep water currents)
OCEAN Tides
Caused by the gravitational pull of the sun and moon
Remember the tidal range and the adaptations of the organisms in the intertidal zone
ATMOSPHERE Origin – remember the Miller and Urey
experiment
Evolution - Primitive Earth’s atmosphere was very different in the first few hundred million years (probably hydrogen and helium) and only changed as comets, volcanoes, and other sources of elements entered the picture.
COMPOSITION OF THE ATMOSPHERE 78% Nitrogen 21% Oxygen 0-4% H2O(g)
The other 1% is all other elements (Ex.: Ar, CO2, Ne, He, CH4, H2, O3, etc.)
LAYERS OF THE ATMOSPHERE 0-7 mi above surface – troposphere
Most of Earth’s weather happens here; 75% of the atmosphere’s mass is in this layer; temperature decreases with height. The tropopause is the transitional layer between troposphere and stratosphere
13-30 mi – stratosphere Most jet travel happens here; the protective ozone
layer causes the temp to increase with height in this layer (ozone layer aborbs some ionizing radiation) The stratopause is the transitional layer before the mesosphere
31-50 mi – mesosphere Contains some ice-crystal clouds; temperature
decreases with height in this layer; this is the coldest layer of atmosphere. Mesopause comes next
LAYERS OF THE ATMOSPHERE 52-300 mi – thermosphere
Includes the Ionosphere Aurorae; meteors burn up in this layer;
temperature increases with height due to X-rays, gamma rays, and ultraviolet radiation from the sun
300-6000 mi – exosphere This is the transitional layer that leads you to outer
space. The atmosphere slowly decreases in density until you are into interstellar space. H and He exist in this layer.
WEATHER Temperature, pressure, moisture, global
wind patterns (and correlating Coriolis Effect), latitude, natural cycles of the solar system all come in to play in weather.
Global winds caused by convection currents.Tradewinds, prevailing westerlies, and polar
easterliesThese winds also help to distribute solar
heat around the globe. Hadley, Ferrell, and Polar cells
CLOUDS Clouds form when you have warm, moist
air rise and condense
The mechanism that causes the rise may vary Density difference (cold sinks, warm rises)
fronts Mountains (air forced upward over a mountain
top is called orographic lifting)
CLOUD NAMES Clouds are named by their appearance
and altitudeCumulus means “heap” Stratus means “layer”Cirrus means “curl of hair” or “whispy”Nimbus means “rain”
“Cirro-” refers to a high level cloud (made of ice crystals)
“Alto” refers to a mid-level cloudLow-level do not necessarily have a prefix
Ex. Altocumulus clouds are mid-level clouds that look puffy and billowy
WEATHER FRONTS Cold front – a cold air mass that comes in
at ground-level (cold, dense air) Warm front – a warm air mass that moves
into an area (warm air is less dense, so it “wedges” over the cooler air in front of it)
Occluded front – Cold air mass overtakes the warm air mass in front of it, wedging the warm air upward and between the two colder air masses
Stationary front – two fronts moving in opposing directions meet and neither advances
ASSOCIATED WEATHER Cold front – warm moist air lifted quickly
upward, so there can be large, powerful thunderstorms (some with hail)
Warm front – cirrus clouds come in first, then a steady drizzle can happen. More gradual weather change than we see with a cold front
Cold front forcing warm, moist air upward, resulting in a vertical development cloud (severe t’storm)
Warm front moving into area, gradually lifting and causing cirrus clouds to form.
Station Models
Shows the current weather for a specific site (a snapshot of weather that can be reported to news stations, ex.)
SEVERE WEATHER Hurricane – cyclonic, low pressure system
that is fueled by the warm ocean waters. It forms off the coast of Africa and builds in strength as it moves west in band of trade winds. As it hits land (N. America) it moves east due to our prevailing global winds, loses strength and “dies out” over cooler ocean waters or land. (Saffir Simpson scale)
Tornado – cyclonic, low pressure system that is formed because of the turbulence and wind shear associated with severe thunderstorms. (Enhanced Fujita scale)
CLIMATE Weather is the short-term variation in
atmospheric conditions.
Climate is a long-term variation in the atmospheric condition (an accumulation of at least 30 years’ worth of data)
There are natural and anthropogenic causes to the changes in Earth’s changing climate.
MILANKOVITCH CYCLES
The collective effect of changes in Earth’s movements upon its climate
Earth's perihelion and aphelion-Earth is closest to the Sun (perihelion) in early January and farthest (aphelion) in early July. -The relation between perihelion, aphelion and the Earth's seasons changes over a 21,000 year cycle.
Axial tilt, precession and eccentricity of Earth's orbit vary in several patterns, resulting in 100,000-year ice age cycles over the last few million years.
The Earth's axis completes one full cycle of precession approximately every 26,000 years.
-Precession refers to the movement of the rotational axis of a body (like a spinning top as it wobbles)
The eccentricity of Earth’s orbit is currently about 0.0167. (how far from circular the orbit is) Over thousands of years, the eccentricity of the
Earth's orbit varies from nearly 0.0034 to almost 0.058 as a result of gravitational attractions between the planets.
The elliptical orbit rotates, more slowly, leading to a 21,000-year cycle between the seasons and the orbit.
The angle between Earth's rotational axis and the normal to the plane of its orbit moves from 22.1 degrees to 24.5 degrees and back again on a 41,000-year cycle. Currently, this angle is 23.44 degrees and is
decreasing.
Milankovitch Variations
OTHER NATURAL EVENTS Sunspot cycles
A 22-year cycle of min & max # of sunspots Volcanic eruptions
Cause general cooling of Earth due to particulates blocking sun’s rays
El Nino Southern Oscillation (ENSO) Also in a cycle that affects coastal AND inland
regions; can greatly change that year’s precip/temp/storm amounts
Greenhouse Effect (Enhanced) Greenhouse effect makes conditions conducive
to life on Earth (amt of greenhouse gases) Too much of a “good thing” causes increased
heating
EFFECTS OF CLIMATE CHANGE Reduction in sea ice and
change in albedo Decrease in seasonal ice
melt to local watersheds Higher ocean levels that
may flood coastal population centers
Spread the range of disease-carrying vectors that are indigenous to warmer climates
Extinction rates will increase when the natural evolution and co-evolution (re: adaptations) cannot keep up with a shift in biotic/abiotic factors
Biodiversity of coral reefs will decrease as ocean temps increase, causing bleaching
Methane hydrate released into atmosphere from melting permafrost (greenhouse gas) as well as damage to structures already in place in those regions
Warmer oceans will allow for increased rates of evaporation, giving more energy to storms (increased storm intensity or more incidences)
Seasons
SEASONSResult from Earth’s axis being tilted to its
orbital plane at an angle of approx. 23.5 degrees and Earth’s position in its orbit.
At any given time during summer or winter, one part of the planet is more directly exposed to the rays of the Sun (more direct sun rays = summer)Aphelion in summer/perihelion in winter for N
hemisphereThis exposure alternates as the Earth
revolves in its orbit. N and S hemispheres experience opposite
seasons.
CASE STUDIES Yellowstone Hotspot Coastal Vulnerability to Rising Sea
Levels Coastal Vulnerability to Hurricanes El Nino and Landslides
CITATIONSMiller, G T. Living In the Environment. 13th ed.
Pacific Grove, CA: Brooks/Cole, a division of Thomson Learning, 2004. Print.
Oak Ridge National Laboratory. Web. 20 Apr. 2014.
<http://orise.orau.gov/reacts/guide/define.htm>.
Reel, Kevin R. AP Environmental Science. 2nd ed. USA: Research and Education Association, 2008. Print.
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