Term
| What is the Catastrophic Model? |
|
Definition
| Earth’s surface features have been effected by sudden events: High magnitude, Low frequency and Biblical floods. |
|
|
Term
| What is Uniformitarianism? |
|
Definition
| Current processes and natural laws apply throughout the length of time. |
|
|
Term
| The two fathers of modern geology are? |
|
Definition
James Hutton:
Theory of the Earth (1785),
Different types of rocks interposed,
Sedimentary.
Charles Lyell:
Principles of Geology (1830). |
|
|
Term
| What is Neocatastrophism? |
|
Definition
| High magnitude, low frequency events of the Earth’s moon. It is the end of the Cretaceous period. |
|
|
Term
|
Definition
Any process that changes the Earth’s surface:
Build up -
Tear down.
Much diastrophism can explained with plate tectonics:
Volcanism:
Movement of Magma and
Earthquakes. |
|
|
Term
| The four Force Acting on a Solid Material are: |
|
Definition
4 Possible Responses:
Nothing:
Material can resist a weak force
Elastic Change:
Material will revert to initial shape once force is removed
Plastic Change:
Change will persist even if force is removed
Dent
Break. |
|
|
Term
| What is the difference between Stress and Strain? |
|
Definition
Stress:
Force acting on a rock -
Compress, pull apart, or deform
Strain:
Adjustment to the stress. |
|
|
Term
| What are the type of stresses? |
|
Definition
Three Types of Forces:
Compressive -
Two plates moving together OR
One plate moving into a stationary one
Tensional -
Plates moving away
Shear -
Two plates sliding past each other OR
One moving past a stationary |
|
|
Term
| What are the Types of Strain? |
|
Definition
3 Types
Elastic Strain
Rocks recover original shape after stress is released
Plastic Strain
Rocks change shape
Fracture Strain
Rocks crack or break |
|
|
Term
| What are the determinants of Strain Types? |
|
Definition
Nature of the Rock
Temperature
Heat energy favors permanent, plastic changes
Cold rocks break more easily
Time Scale
Fast changes break
Confining Pressure
Greater depth = higher pressure
Plastic changes |
|
|
Term
| What are Sedimentary Rocks? |
|
Definition
| Usually occur in flat layers as sediment is deposited along the bottom of a body of water. |
|
|
Term
|
Definition
Bends in layered bedrock.
Plastic strain.
Causes:
Plates colliding and
Magma super plumes.
Any rocks can fold, but its easiest to see in sedimentary. |
|
|
Term
| What are the types of folding? |
|
Definition
Anticline
Arch shaped fold .
Syncline
Trough shaped fold
San Joaquin Valley
Barstow Syncline |
|
|
Term
|
Definition
Relative movement of rocks on either side of a fracture
Breaks occur more often near the surface
Cooler and less pressure
Also occur near ore veins |
|
|
Term
| What are the three types of faulting? |
|
Definition
Footwall
Mass of rock below the fault
Hanging Wall
Mass of rock above the fault
Fault plane
Surface between the two walls |
|
|
Term
| What are fault movements? |
|
Definition
Dip
Walls move up and down
Strike
Walls move horizontally
Oblique
Movement has both vertical and horizontal characteristics |
|
|
Term
| What is Fault Classification? |
|
Definition
Normal
Hanging wall moves down relative to footwall
Graben
Block of hanging wall surrounded by faults
Horst
Block raised up
Fault block mountains
Result from pulling apart stress |
|
|
Term
| What is the Fault Classification: Reverse and Thrust? |
|
Definition
Reverse
The hanging wall has moved upward relative to footwall
Thrust
Reverse fault with a low angle fault plane
Result from compressional stress |
|
|
Term
| What are Magma Superplumes? |
|
Definition
Plumes of molten rock that rise toward the surface:
From the base of the mantle -
Heated from the core -
Exerts pressure on the lithosphere from underneath. |
|
|
Term
|
Definition
Quaking, shaking, vibrating or upheaval of the ground -
Stress on rocks under Earth’s surface:
Sudden release of energy -
Seismic waves -
Vibrations that travel out from the sudden release of energy -
Fault planes:
Most frequent source. |
|
|
Term
| What are the causes of earthquakes? |
|
Definition
Two plates press against each other.
Friction vs. motion -
Stress builds until rupture point is reached:
Snaps into new position. |
|
|
Term
| How do you locate and measure Earthquakes? |
|
Definition
Triangulation
P-waves travel faster than S-waves
Focus:
Actual origin of the seismic waves.
Epicenter:
Location on Earth’s surface directly above focus.
Seismometer:
Detects and measures earthquakes -
3 types of waves
S-waves
P-waves
Side to side waves. |
|
|
Term
| How do you locate an Epicenter? |
|
Definition
P-waves travel faster than S-waves -
Difference in arrival times correlates to distance from earthquake -
Triangulation used to pinpoint epicenter and focus. |
|
|
Term
| What is the Quantification of Earthquakes? |
|
Definition
Richter Scale -
Swing is seismograph recording |
|
|
Term
| What is the Good Friday Earthquake? |
|
Definition
9.2 on 27 march, 1964 -
2nd Largest ever measured.
Casualties:
15 Earthquake
128 Tsunamis.
Tsunamis felt as far away as Japan and Hawaii.
67 meter wave in Valdez.
Anchorage, Alaska -
Subduction of Pacific plate under the North American plate |
|
|
Term
|
Definition
Very large ocean waves.
Generated by strong disturbance in ocean floor:
Earthquake, landslide, volcanic explosion.
Speeds of up to 725
km/h (459 mi/h).
Wave height can be
over 8 m (25 ft).
Very long wavelength
of up to 200 km (120 mi). |
|
|
Term
| What is the origin of Mountains? |
|
Definition
Origen:
Forces leading to the deformation of earth’s surface as a result of tectonic plate activity.
Mountains:
Elevated parts of Earth’s crust.
Created by folding and faulting of crust.
Three basic origins:
Folding
Faulting
Volcanic activity |
|
|
Term
| What is the Folding in the Appalachians? |
|
Definition
Tight, almost vertical, folds.
Weathered edges. |
|
|
Term
| What are the Appalachian Mountains? |
|
Definition
Plate collision:
Folded and faulted (thrust) sedimentary rocks.
Some Scottish mountains.
Anti-Atlas Mountains in Morocco. |
|
|
Term
|
Definition
Fold mountains:
Indo-Australian plate and Eurasian plate.
Peaks include Everest (8,848m) and K2 (8,611m). |
|
|
Term
| What are Domed Mountains? |
|
Definition
Broad, Arching Fold:
Igneous intrusion
Uplifting of sedimentary layers around a center.
Granite peaks exposed by erosion of sedimentary cover.
Ozarks.
Black Hills, SD. |
|
|
Term
| What are Fault Block Mountains? |
|
Definition
Fault block mountains:
- Rise sharply along steeply inclined fault planes
- Weathering erodes sharp edges.
Tetons, Utah.
Sierra Nevada, California. |
|
|
Term
| What are Volcanic mountains? |
|
Definition
Volcano:
A hill or mountain formed by the extrusions of lava or rock fragments from magma below.
Cascade Mountains |
|
|
Term
| What are Composite Volcanoes? |
|
Definition
Steep, symmetrical sides:
Periodic, explosive eruptions.
Common in subduction zones.
Mount Fuji, Mount Shasta, Mount Hood, Mount Rainier. |
|
|
Term
|
Definition
Steep walled depression resulting from an explosion.
Cinder cone island.
Crater Lake, OR
Formed ~6000 years ago |
|
|
Term
| What is a Shield Volcano? |
|
Definition
Gentle slope to cone:
- Basaltic lava has a different viscosity.
- Long vents rather than central vents.
Hawaiian volcanoes.
Mauna Loa:
13,677 ft above sea level.
Kilauea.
Cascades:
Belknap and Mount Bachelor in Oregon. |
|
|
Term
|
Definition
Molten rock:
Variety of minerals.
Gases:
Water vapor, sulfur dioxide, hydrochloric acid, hydrogen sulfide, carbon dioxide.
Gases can be a driving source to the surface.
Lava:
Magma at the surface. |
|
|
Term
|
Definition
Streams of molten rock from erupting vent:
Explosive or non-explosive.
Accumulated horizontal lava flows.
Columbia Plateau. |
|
|
Term
| What are Volcanoes and Plate Tectonics? |
|
Definition
Convergent:
Subduction zones.
Batholith:
Intrusive igneous rock.
Dike:
Narrow projection of igneous rock.
Laccolith:
Igneous intrusion between layers of sedimentary rock.
Divergent:
Mid-Atlantic ridge.
Not Transform boundaries. |
|
|
Term
| What is the Devil’s Tower? |
|
Definition
Magma intrusion into sedimentary rock:
Erosion of softer sedimentary rock.
National Monument:
1st declared.
Theodore Roosevelt.
Volcano. |
|
|
Term
|
Definition
Ridge with approximately equal slopes.
Upturned sedimentary beds.
In Colorado. |
|
|
Term
|
Definition
Weathering:
Slow changes resulting in the breakup, crumbling and other destruction of solid rock. |
|
|
Term
|
Definition
| The process of physically removing weathered materials |
|
|
Term
| How are things transported? |
|
Definition
| Stream, river, wind, glacier, etc |
|
|
Term
| What is Mechanical Weathering? |
|
Definition
The physical breakup of rocks without chemical change:
Wedging:
Frost
Trees |
|
|
Term
|
Definition
The physical breakup of rocks without chemical change:
Exfoliation:
Reduced pressure effect.
Fractures caused by expansion of underlying rock.
Granite boulders:
Stone Mountain, GA
Adirondacks |
|
|
Term
| What is Chemical Weathering? |
|
Definition
Decomposition of minerals by chemical reactions:
Oxidation
Carbonation
Hydration |
|
|
Term
| What is Chemical Weathering: Oxidation? |
|
Definition
Reactions with oxygen:
Rusting.
Produced red iron oxides:
Hematite.
Produces red soils:
Colorado, Oklahoma, Georgia. |
|
|
Term
| What is Chemical Weathering: Carbonation? |
|
Definition
Reactions with carbonic acid (H2CO3).
Carbon dioxide (CO2) dissolved in water.
Rain.
Easily dissolves limestone.
Soluble Minerals:
Those containing calcium, magnesium, sodium, potassium and iron.
Carlsbad Caverns:
‘Big Room’.
1200m x 190m. |
|
|
Term
| What is the Sarawak Chamber? |
|
Definition
Limestone cave:
Borneo.
Largest underground chamber in the world:
700m x 400m. |
|
|
Term
| What is Chemical Weathering: Hydration? |
|
Definition
Reactions with water:
H2O ⇌ H+ + OH-.
Silicates are susceptible:
Feldspar, orthoclase, olivine.
Also includes dissolving in water:
Often works in concert with carbonation. |
|
|
Term
|
Definition
Physically moving weathered materials:
Gravity alone.
Gravity acting on an intermediary.
Mass movement:
Erosion caused directly by gravity.
Creep:
The slow movement of soil down a steep slope.
Landslide:
Any slow to rapid downhill movement of materials. |
|
|
Term
|
Definition
Several types of processes:
Physical
Chemical
Biological
Contributes to:
The rock cycle
Formation of sediments
Formation of soils
Soil is particulate mineral matter and organic matter
Movement of rock materials over Earth’s surface. |
|
|
Term
|
Definition
Most important of all gravitational erosion processes.
Three stream transport mechanisms.
Dissolved materials
Suspended materials
Rolling, bouncing and sliding along stream bed
Streambed evolves over time. |
|
|
Term
| Stream Development: Youth |
|
Definition
Youth:
Landmass recently uplifted.
Steep gradient.
V-shaped valley w/o floodplain.
Boulders, rapids and waterfalls.
Characteristics present closest to source of stream. |
|
|
Term
| Stream Development: Maturity |
|
Definition
Maturity
Stream gradient smoothed and lowered
Meanders over floodplain
Oxbow lake
Two bends meet |
|
|
Term
| Stream Development: Old Age |
|
Definition
Old age
Very low gradient
Broad, gently sloping valleys
Sluggish flow; more floods
Characteristics present closer to deposition into a body of water
Floodplain
Wide, level floor of a valley built by a stream |
|
|
Term
|
Definition
Deposits of sediment at the mouth of a river or stream.
Stream flow dissipates into an ocean or lake .
Erosive and sediment-carrying abilities lost. |
|
|
Term
|
Definition
Masses of ice on land that move under their own weight.
Compacted snow:
Blue.
Form from snow accumulated over a number of years (5-3500):
10% of current surface covered in glaciers. |
|
|
Term
| What are the Types of Glaciers? |
|
Definition
Alpine:
Form at high elevations
Flow through valleys
U-shaped valleys
Valley glaciers
Continental:
Cover large areas of a continent
Currently found in Greenland and Antarctica |
|
|
Term
|
Definition
Three mechanisms:
Bulldozing
Abrasion
Plucking |
|
|
Term
| What are Glaciers: Bull-Dozing? |
|
Definition
Pushing material in front of advancing glaciers.
Moraine:
Deposits of soil and rock left by glaciers. |
|
|
Term
| What are Glaciers: Plucking? |
|
Definition
Water seems into cracks in rocks:
Freezes to become continuous with a glacier.
Glacial movement picks up attached rocks.
Cirque. |
|
|
Term
| What is Glaciers: Abrasion? |
|
Definition
Rock fragments imbedded in ice:
Scratch, polish, and grind.
Cirque:
Bowl like depression caused by plucking, then subsequent abrasion. |
|
|
Term
|
Definition
Considerably less efficient than water or ice.
Two major processes:
Abrasion
Natural sandblasting
Produces ventifacts
Shape can depend on prevailing winds
Deflation
Loose material picked up and carried away by the wind
Wind-blown deposits:
Dunes: low mound or ridge of sand or other sediment
Loess: fine dust deposited over a large area |
|
|
Term
| What is Hoodoo/Tent Rock? |
|
Definition
Sedimentary rock protected from erosion by more resistant rock on top.
American Southwest, Taiwan, Turkey |
|
|
Term
|
Definition
A relatively thin shell of gases surrounding the solid Earth.
Density decreases with increasing altitude. |
|
|
Term
|
Definition
Air density:
Number of gas molecules in a defined volume.
Decreases with increasing altitude. |
|
|
Term
| What are the major components of the atmosphere? |
|
Definition
| Mostly nitrogen (78%), oxygen (21%) and argon (1%) |
|
|
Term
| What are Trace Components? |
|
Definition
Water
carbon dioxide
neon, helium, krypton, xenon, hydrogen, methane, nitrous oxide, …
Aerosols:
Suspended Particles
dust, smoke, salt and other tiny solid or liquid particles
<500 micrometers |
|
|
Term
| What is the Nitrogen Cycle? |
|
Definition
Removed from Atmosphere
Bacteria
Free-living
Symbiotic
Lightning
Not reactive with minerals
Biological Events
Amino acids, DNA
Plant biomass
Returned to Atmosphere
Decay of biological matter |
|
|
Term
| What is the secondary cycle of the nitrogen cycle? |
|
Definition
Secondary Cycle
Nitrogen cycled through surface/biological components without returning to atmosphere |
|
|
Term
| What is the Oxygen cycle? |
|
Definition
Removed from Atmosphere
By living organisms
Food + O2 → H20 + CO2
Respiration
Chemical weathering
Oxidation
Returned to Atmosphere
Released during photosynthesis
6 CO2 + 6 H20 + sunlight → C6H1202 + 6 O2 |
|
|
Term
|
Definition
Water Vapor
Water in gaseous state
Warm air holds more water vapor
Up to 4% water vapor
Clouds and fog
NOT gaseous
Suspended, liquid droplets
Removed from Atmosphere
By precipitation
Returned to Atmosphere
Evaporation
Liquid to gas
Sublimation
Solid to gas
Removed from Atmosphere
By precipitation
Returned to Atmosphere
Evaporation
Liquid to gas
Sublimation
Solid to gas |
|
|
Term
| How do you measure atmospheric pressure? |
|
Definition
Barometer:
pressure measuring device
Mercury barometer
Depends on atmospheric pressure supporting a column of mercury
Standard atmospheric pressure (1 atmosphere) corresponds to 76.00 mm of Hg
Units of measure
mmHg, inches of Hg
PSI, N/cm3, atm |
|
|
Term
| What is indirect and direct heat? |
|
Definition
Direct heating
16% absorbed by air
3% absorbed by clouds
Indirect heating
51% absorbed by surface
Infrared reemitted by surface and absorbed by atmosphere
Involves water and CO2
Greenhouse effect |
|
|
Term
| What is the greenhouse effect? |
|
Definition
Indirect heating
51% absorbed by surface
Surface reemits infrared radiation
Absorbed by gasses (water and CO2)
Remitted by gasses
Cycles back into heating the surface
More CO2 results in more heating of surface |
|
|
Term
| What is the structure of the atmosphere? |
|
Definition
Temperature generally decreases with increasing altitude
Heating mechanisms more efficient at lower altitudes
Cooling mechanisms more pronounced at higher altitudes
Observed lapse rate is 6.5ºC per km
Average
Air not moving
Inversion:
Colder temperatures near surface |
|
|
Term
|
Definition
Temperature generally decreases with increasing altitude
Inversion:
Colder temperatures near surface
Calm winter days with a cold front
C nights
Calm, cold, clear
Little heat trapped by clouds or other insulators
Cold air
Doesn’t rise
Trapped by warmer air above
Pollutants |
|
|
Term
|
Definition
Troposphere
Surface to ~11km altitude
Greek: ‘turning’ or ‘mixing’
Surface to where temperature stops decreasing with height
Most weather here
Water vapor
Tropopause
Border |
|
|
Term
| What is the Stratosphere? |
|
Definition
Stratosphere
11 – 48 km
Temperature increases with height
Less turbulent layer
Aircraft
Ozone (O3) |
|
|
Term
| What is the Ozone in the Stratosphere? |
|
Definition
Ultraviolet light
DNA damage and cancer
Eye damage
Ozone (O3) protects surface of Earth from ultraviolet light
O2 + UV light → O + O
O2 + O + Neutral molecule → O3 + Neutral molecule
O3 + UV light → O2 + O
O3 + O → 2O2
Chlorofluorocarbons (Freon, CFCs)
Breakdown in atmosphere releases Cl that reacts with ozone
Regions of decreased ozone availability
Increased UV damage |
|
|
Term
|
Definition
Merges with vacuum of space
Free electrons and ions
Northern lights |
|
|
Term
|
Definition
Three general motions
Upward movement over a region of greater heating
Sinking of air over a cooler region
Horizontal movement between warmer and cooler regions
Wind: this horizontal movement of air |
|
|
Term
| What is Air Temperature and Density? |
|
Definition
Air temperature and air density
Density decreases with temperature
Hot air rises; colder air sinks
Air pressure and air movement |
|
|
Term
|
Definition
| The transfer of heat through the movement of a liquid or gas |
|
|
Term
| What is Air Pressure and Movement? |
|
Definition
Lifting Effect
Upward movement of air leaves a low pressure
Piling Up Effect
Downward movement increases pressure
Moves from High to low pressure regions |
|
|
Term
|
Definition
Land warms and cools more quickly than water
Day
Breezes blowing in from water
Night
Breezes blowing out from land |
|
|
Term
|
Definition
Land warms and cools more quickly than water
Specific heat of water is
2x the specific heat of soil
Amount of heat required to raise the temperature of a material
Water requires more heat energy to change temperature
Water warms throughout
Transparent
Fluid
Water cools by evaporation |
|
|
Term
|
Definition
Wind blowing up the side of a mountain
Solar radiation more direct on sloped surfaces
Air above slope heated more thoroughly - lifts
Can form clouds at the mountains’ peak |
|
|
Term
|
Definition
Cold air accumulates in a valley
Moving fronts can compress this air mass
Compression increases temperature |
|
|
Term
| What is Global wind patterns? |
|
Definition
Earth receives more direct solar radiation in the equatorial region
Analysis long term trends reveals belts
Wind direction
High pressure averages
Low pressure averages
Model effects local weather forecasting |
|
|
Term
| What is the Intertropical Convergence Zone? |
|
Definition
Intertropical convergence zone
Equatorial
10°N to 10°S
Hot air rises here
Rising air cools, causing precipitation
Tropical rainforests |
|
|
Term
| Subtropical High Pressure |
|
Definition
Cooler air descends at higher latitudes
Already lost moisture over the tropical rainforests
Deserts
Sahara, SW US, Kalahari, Australian Desert
High pressure belt 30°N&S of equator
aka ‘Horse Latitudes’ |
|
|
Term
|
Definition
35°-65°
From West to East
High pressure descent in the Horse Latitude heads to low pressure at poles
If high pressure at poles, then low force to Westerlies |
|
|
Term
|
Definition
Between horse latitudes and intertropical convergence zone
Northeast in the N. Hemisphere
Southeast in the S. Hemisphere
Movement of tropical storms |
|
|
Term
|
Definition
Meandering loops of wind near the top of the troposphere
Speeds of >100 mph
Belts
Crest
Occur near the poles
Trough
Occur near the equator |
|
|
Term
|
Definition
Three phases of water
Liquid generally above 0ºC (98% of Earth’s water)
Solid below 0ºC in the form of ice, snow and hail
Water vapor
Smallest component of the three
Contributes to greenhouse effect
One of the principal weathering and erosion agents
Responsible for maintaining life on land |
|
|
Term
|
Definition
Evaporation
Liquid to gas phase shift
Condensation
Gas to liquid phase shift
Both occur at any temperature
Liquid molecules with higher than average kinetic energy can evaporate
Gas molecules with lower than average kinetic energy can condense |
|
|
Term
| Evaporation and condensation |
|
Definition
Liquid-to-gas and gas-to-liquid phase changes occur at any temperature
Liquid molecules with higher than average kinetic energy can evaporate
Gas molecules with lower than average kinetic energy can condense |
|
|
Term
|
Definition
Saturation
Equilibrium between evaporation and condensation
Stable environment
Influenced by temperature
Warm air can hold more water vapor than cold air |
|
|
Term
|
Definition
Amount of water vapor in the air
Absolute humidity
The amount of water vapor in the air at a particular time
Ranges from near zero to the temperature dependent saturation limit |
|
|
Term
|
Definition
Capacity of air to hold water changes with temperature
As capacity increases, relative humidity decreases |
|
|
Term
|
Definition
Condensation factors
Relative humidity
Temperature of the air
Water molecules join together to:
produce a liquid
On a surface as dew
In the air in droplets
to produce a solid
As frost on a surface
As snow in the air |
|
|
Term
| Condensation And Saturation |
|
Definition
Air must be saturated for condensation to occur
Saturation processes
Water vapor added to the air via evaporation
Seeing your breath on a cold day
Jet aircraft contrails
Cooling reduces the capacity of the air to hold water vapor
The dew point
Temperature at which condensation begins
A combination of 1. and 2. |
|
|
Term
|
Definition
Form on surfaces at ground level
Dew and frost tend to form on cool, clear and calm nights
Related to radiative cooling of surfaces
Grass blades have relatively high surface areas
Cooling occurs in low-lying areas near the surface
Temperature drops below dew point
Condensation
Condensation Nuclei
Non water
Particulate matter
Salt
Dust, ash, soot, etc |
|
|
Term
|
Definition
Fog - near the ground; clouds - higher up
Comprised of small, suspended water droplets
Form around condensation nuclei |
|
|
Term
|
Definition
Radiation Fog
Cool, calm, clear nights when the surface cools quickly
Stationary
Valley fog
Advection Fog
Moist air moves into a cooler region
Ocean to land winds
Precipitation Fog
Rain falls into cooler, drier area
Evaporates from ground
Condenses due to low dew point |
|
|
Term
|
Definition
Fog - near the ground; clouds - higher up
Comprised of small, suspended water droplets
Cloud classification schemes
1803 Classification
Luke Howard
Cirrus (curly, wispy)
Cumulus (piled up)
Stratus (spread out) |
|
|
Term
|
Definition
Form when a mass of air above the surface is cooled to its dew point temperature
Usually because air pushed into higher levels in atmosphere
Three major causes of upward air movement
Convection
Differential heating
Mountain Ranges
Barriers to moving masses
Colliding air masses with different densities
Cloud formation depends on atmospheric stability |
|
|
Term
|
Definition
Stable atmosphere (air mass)
Lifted parcel of air is cooler (and denser) than surrounding air
Lifted parcel returns to its original level
Unstable atmosphere (air mass)
Lifted parcel of air is warmer (and less dense) than surrounding air
Moved to a higher level, it will continue to rise
“thermals” |
|
|
Term
| Upward mobility and moist air |
|
Definition
Rising moist air cools and eventually reaches the dew point
Droplets condense around condensation nuclei in saturated air
(No condensation nuclei: supersaturated air)
Cooling of rising air slowed by release of latent heat of vaporization
Huge numbers of droplets appear as clouds |
|
|
Term
|
Definition
Precipitation
Water returning to Earth’s surface
Dew and frost are surface processes, not precipitation
Precipitation forms in two ways
Coalescence of cloud droplets
Growth of ice crystals |
|
|
Term
| Origin of Precipitation: Coalescence |
|
Definition
Coalescence process
Takes place in warm cumulus clouds near the tropic oceans
Clouds contain giant salt condensation nuclei
Often form over oceans in the tropics |
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Term
| Origin of Precipitation: Ice Crystal |
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Definition
Freezing Point of Water:
32°F (0°C)
Tiny droplets don’t freeze as readily
-40°F (=40°C)
Supercooled clouds
Ice-crystal process
Takes place in clouds at middle latitudes
Ice crystals capture nearby water molecules and grow
Similar to condensation nuclei
Fall as snow in the winter; melt and turn to rain in summer |
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Term
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Definition
Cirrus
No precipitation
Cumulus
Brief showers or thunderstorms
Stratus
Drizzle, rain, snow of long duration
Seeding
Artificial ice crystals into clouds
Silver iodide |
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Term
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Definition
Idealized model
Region 10ºN and 10ºS of equator receives more direct solar energy
Intercontinental Convergence Zone
Air heats up, rises and spreads toward poles
Air cools and becomes more dense as it rises, sinking back to the surface at latitudes 30ºN and 30ºS
Horse Latitudes
End result
Band of low pressure near the equator, bands of higher pressure 30ºN and 30ºS of the equator
Large convective cells form to equalize pressure |
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Term
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Definition
Large, horizontally uniform bodies of air
Moisture
Temperature
Dictate air mass weather
Weather conditions remain the same over several days
Weather changes when a
New mass moves in OR
Acquisition of local conditions |
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Term
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Definition
Air takes characteristics of surface
Moisture
Condensation and Evaporation
Temperature
Conduction, convection and radiation
4 Types:
Continental Polar
Maritime Polar
Continental Tropical
Maritime Tropical
Move up to 800 km/day |
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Term
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Definition
Boundaries between air masses at different temperatures
Transition Zone
5-30 km
Only site of mixing
Different density prevents further mixing |
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Term
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Definition
Cold air mass moves into and displaces warmer air upward
Moist rising air cooled, leading to large cumulus and thunder clouds |
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Term
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Definition
Warm air moves in over a mass of cooler air
Long, gentle sloping front
Clouds form far in advance of the warm air at ground level
Light, steady precipitation |
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Term
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Definition
Not advancing
Balance between forces influencing cold and warm fronts
Cold air moves along the north side
Warm air moves along the south side
Not stable |
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Term
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Definition
Stationary front (or slow, cold front)
Mechanism
Bulges or waves often form between oppositely moving air masses
Overriding, uplifted cold air produces a low pressure area
Further cold front motion leads to an occluded front and a cyclonic storm |
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Term
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Definition
Occluded Front
Air mass that has been completed lifted from the surface
Low pressure area with characteristic air movement
Inward
Upward
Cools
Clouds as vapor condenses |
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Term
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Definition
High pressure area
Also called a ‘high’
Air sinks, is warmed and relative humidity is lower
Warmer air can hold more water vapor
Clear skies
Cooler, drier air
Clockwise in Northern Hemisphere, counter clockwise in Southern |
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Term
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Definition
Rapid, violent weather changes
Often associated with frontal passage
Three major types
Thunderstorms
Tornadoes
Hurricanes |
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Term
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Definition
Usually develop in warm, very moist, and unstable air
‘Cells’ of air
2-8 km
Last about an hour
Can be multiple cells |
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Term
| Thunderstorms: Cumulus Stage |
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Definition
Uplift of a parcel of air
Forms cumulus clouds
Convection
Warm, humid afternoons
Mountain barriers
Occluded or cold front
Any time of day
Moves along front |
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Term
| Thunderstorms: Mature and Final Stages |
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Definition
Three stages of each cell
Cumulus
Updrafts
Mature
Precipitation
Updraft can no longer support growing ice crystals and snow flakes
Falling frozen water melts and becomes rain
Downdraft
Falling rain and cool air
90 km/hour
Hail formed through ice accumulation cycles
3. Final stage
Updrafts exhausted
3. Final stage
Updrafts exhausted |
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Term
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Definition
Updrafts, downdrafts and circulating precipitation separate electrical charges
Charges accumulate in different parts of the thunderhead
Lightning
Discharge between charge centers
Discharge can be cloud to ground, ground to cloud or cloud to cloud
Expanding pressure wave from heated air produces crack of thunder |
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Term
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Definition
Frozen precipitation
Irregular, spherical or flattened forms of ice
Alternating layers of clear and opaque ice
Believed to form as hailstone cycles through falling and returning to upper parts of thundercloud
Collect supercooled water |
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Term
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Definition
Smallest, most violent weather disturbance
Rapidly whirling column of air
Diameter of 100-400 meters
Wind speeds up to 480km/h
Damage produced by high winds, drop in pressure at the center, and flying debris
Associated with intense thunderstorms |
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Term
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Definition
Cyclonic movement over tropical or subtropical waters
Tropical depression
Area of low pressure
Winds generally moving 55km/h or less
Tropical storm
More intense low pressure area
Winds between 56 and 120 km/h
Hurricane
Very intense low pressure
Winds in excess of 120 km/h
Fully developed hurricane has a calm eye surrounded by intense rain and thunderstorms |
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Term
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Definition
Based upon mathematical models of the atmosphere
Billions of calculations necessitate use of supercomputers
Fairly accurate forecasts up to three days possible
Major uncertainty: insufficient technology to connect small and large scale events
Ultimately oceanic influences need to be better understood
Major uncertainty: insufficient technology to connect small and large scale events
Ultimately oceanic influences need to be better understood |
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Term
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Definition
Composite, larger weather patterns occurring over a number of years
Determining factor in
Types of plants and animals at a given location
Types of houses built
Lifestyles
Influences
Shape of the landscape
Types of soil
Agricultural type and productivity |
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Term
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Definition
Two primary factors
Intensity of incoming solar radiation
Determined by angle of incidence
Number of daylight hours
Tilt of Earth’s rotation axis
Equatorial regions receive more solar radiation
Intensity changes on a yearly basis
Number of daylight hours varies annually |
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Term
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Definition
Low latitudes
High solar radiation
Yearly variation small
Temperatures uniformly high
Middle latitudes
Higher solar radiation during one part of the year; lower during the other
Overall temperatures lower with greater variation than low latitudes
High latitudes
Maximum amount of radiation during one part of the year; none in the other
Overall temperatures are lowest with widest variation |
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Term
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Definition
Defined in terms of yearly temperature averages
Tropical climate zone
Near equator
Receives most solar radiation; hot
Polar climate zone
Least solar radiation; cold
Constant daylight part of summer; constant darkness part of winter
Temperate climate zone
Intermediate between others
Rainfall patterns shift seasonally |
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Term
| Regional climatic influences |
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Definition
Four major factors
Altitude
Higher altitude air radiates more energy into space
Mountains
Cooler air at higher altitudes
Upwind slopes receive more precipitation; downwind slopes less |
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Term
| Regional climatic influences |
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Definition
Large bodies of water
High specific heat of water moderates temperature changes
Ocean currents
Can bring water nearby that has a different temperature than the land |
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Term
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Definition
Problems
No sharp boundaries
No two places have exactly the same climate |
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Term
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Definition
Departure from expected average climate pattern
120 years of direct measurement
Thermometers, rain gauges, barometers
Proxy data
Tree rings, lake sediments, ice cores |
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Term
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Definition
Ice ages dominate the past several million years
Previous: 1/3 of Earth covered in ice
Interglacial Warming Period
Every 100,000 years
Calculations indicate currently approaching the end of the current warming period
Data show current warming trends |
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