ENVS 203- Test 2 Flashcards
Why is there wind?
- energy imbalances, especially between higher and lower latitudes
- energy surplus at the equator
- Energy deficit at poles
- this leads to differences in atmospheric pressure.
What is the relationship between atmospheric pressure and both altitude and temperature?
- pressure decreases with altitude
- warm air is less dense than cool air
What are the relative nature of high/low pressure zones?
-High and low pressure are relative terms - higher/lower than surrounding area
Pressure gradient…what is it and how does it relate to pressure differences?
- pressure gradient: horizontal rate of pressure change
- larger the pressure difference gradient
What are the three main forces/phenomena that produce our wind patterns?
- pressure gradient
- earths rotation/coriolis effect
- friction
How does pressure gradient relate to wind speed and direction?
- winds generated from high pressure ->low pressure
- larger the pressure difference, larger the pressure gradient
- wind speed is directly proportional to pressure gradient
- winds generated perpendicular to isobars from high -> low
How does the coriolis force affect wind speed and direction?
- once generated the wind is turned by earth’s rotation= coriolis effect
- deflects to the right in northern hemisphere, left in southern
- strongest effect at poles, zero at equator
- effect is proportional to wind speed
- effect influences direction only, not speed
- will turn winds 90 degrees to pressure gradient
How does friction affect wind speed and direction?
- friction with the ground slows speed, thus decreasing coriolis effect
- results in winds crossing isolines at 30 degree angle
- friction extends to a height of about 1600 ft
- increases with roughness of a surface
Draw the net result of these forces on wind direction at the surface or aloft
-Look in slides/chapter about wind (lecture slides 9, page 14)
Cyclonic vs. anticlonic circulation. Relation to pressure and direction of air movement both horizontally and vertically
- anticyclone= high-pressure system. circulation body of air outward. descending air. clockwise circulation in northern hemisphere.
- cyclone= low-pressure system. circulating body of air inward. rising air. counterclockwise in northern hemisphere
What is the idea of a constant isobaric surface? (ridges and troughs)
-an elevated surface in the atmosphere on which all points have the same pressure, usually 500 mb. along this constant pressure surface, isobars mark the paths of upper-air winds
Equatorial low-pressure through? (location, climate, how these shift from jan to jul)
- location:intertropical convergence zone
- thermal
- warm/wet
Subtropical high-pressure? (location, climate, how these shift from jan to jul)
- dynamic
- hot/dry
- produce westerlies
- exist above deserts
Subpolar low-pressure? (location, climate, how these shift from jan to jul)
- dynamic
- cool/wet
- polar front is area of contrast between cold air from higher latitudes battling with warm air from lower latitudes
Polar high-pressure? (location, climate, how these shift from jan to jul)
- thermal
- cold/dry
- polar easterlies
- higher latitudes near antarctica
Trade winds? (model of atmospheric circulation)
-northeast and southeast winds that converge in the equatorial low pressure trough, forming the inter tropical convergence zone
Westerlies? (model of atmospheric circulation)
-the predominant wind flow pattern fro the subtropics to high latitudes in both hemispheres
Polar esterlies? (model of atmospheric circulation)
-a variable weak, cold and dry wind moving away from the polar region; an anticyclonic circulation
Hadley cells, mid-latitude cells, polar cells (model of atmospheric circulation)
-
ITCZ (atmospheric circulation)
-a thermally caused low pressure area that almost girdles earth, with air converging and ascending all along its extent
Polar front (model of atmospheric circulation)
-cold polar air meet warm tropical air
Jet streams (model of atmospheric circulation)
-the most prominent movement in upper level westerly wind flows; irregular, concentrated, sinuous bands of geostrophic wind
Describe the direction of flow of the major ocean gyres?
- indian ocean
- north atlantic
- north pacific
- south atlantic
- south pacific
Explain land/sea breezes, mountain-valley breezes, and monsoons?
- land-sea breezes= daily heating/cooling patterns. onshore/offshore flow
- mtn-valley breezes=daily heating/cooling patterns. up valley/downvalley flow.
- monsoons=seasonal heating/cooling patters. high->low
Describe the latent heat exchanges associated with each phase change of water? (know whether heat is real eased or absorbed and the relative amount of heat involved)
- latent heat of melting; +80 calories (absorbed)
- latent heat of vaporization; +540 calories (absorbed)
- latent heat of condensation; -540 calories (released)
- latent heat of freezing; -80 calories (released)
Relative humidity?
a ratio of the amount of water vapor that is actually in the air compared to the max amount of water vapor possible at a given temp
Saturation?
-when a mass of air reaches 100% relative humidity
Dew point?
-temp at which a given mass of air becomes saturated
vapor pressure?
-the amount of pressure exerted by H2O only (expressed in mb)
Specific humidity?
- mass of water vapor (in grams) per mass of air (in kilograms) at any specified temp
- not affected by changes in temp or pressure
Relative humidity’s relationship with temperature, times of day with lowest/highest relative humidity?
- as air temp increases, relative humidity decreases
- relative humidity is highest at dawn and lowest during late afternoon
Relationship between temperature and saturation vapor pressure?
-warmer air can hold more vapor
Dew and frost - how they form?
- dew formation=radiative cooling at night until the dew point is reached at the surface
- frost is when dew point is below freezing
Normal lapse rate, dry adiabatic lapse rate, and moist adiabatic lapse and explain why those aren’t all the same number?
- normal lapse rate= 3.5* (degrees) F / 1000ft
- dry adiabatic rate-<100%RH= 5.5*F/ 1000ft
- moist adiabatic rate-100%RH= 3.3*F/1000ft
- adiabatic refers to the warming and cooling rates for a parcel of expanding or compressing air-depends on moisture conditions in the parcel of air
Explain the concepts of stable vs unstable atmospheric conditions?
- unstable= ELR>DAR &MAR
- stable=ELR<DAR & MAR
What is heating by compression and cooling by expansion for air parcels?
- compression-heats up a gas (air)
- -increase pressure and warms air mass
- -relative humidity will decrease as the air warms
- expansion-cools a gas(air)
- -decrease pressure and cools air mass
- -relative humidity will increase as the air cools
- -saturation occur at the dew point
- -condensation occurs producing clouds
Explain what is required for clouds to form?
- air must be saturated
- condensation nuclei
Describe and provide example locations for the four lifting mechanisms.
- covergent lifting=low pressure area
- convectional=local surface heating
- orgraphic=physical barrier
- frontal lifting=contrasting air masses
Where are global precipitation patterns (high/low areas) and how these relate to lifting mechanisms?
- high=around equator
- in summer=less and higher, then works it;s way down
Cumulus?
- vertically developed
- puffy or cotton
- unstable (rising) air
Stratus?
-layered- nimbostratus if raining, not much vertical movement
Cirrus?
- high, thin clouds
- wispy in appearance
- composed of ice crystals
Lenticular?
-wave cloud formed as moist air blows over mtns
Cirro-, alto-, nimbo(us)?
- cirro=high
- alto=mid
- nimbo(us)=rain
How does fog form? Where is it very common?
- fog forms when surface air is saturated
- radiation
- steam
- valley
- upslope
What is the difference between advection and radiation fog?
- advection fog=warm air flows over a cooler surface-air cools to saturation
- radiation fog=radiative cooling of land surface chills air above dew point
What is an air mass?
-a large body of lower atmosphere with uniform conditions of temperature, moisture, and stability
How do we classify air masses? (c/m, A/P/T/E) What are the properties associated with each? (temp, moisture, stability)
-an air mass is a large body of lower atmosphere with uniform conditions of temp, moisture, and stability.
Moisture content=
1. c-continental-dry
2.m-maritime-moist
-Latitude of source region (surface temp)
1.A or AA=Arctic or Antarctic(cold, dry, stable)
2.P-polar(cold, dry, stable)
3.T-tropical(hot, dry, unstable)
4.E-equatorial
What are the main classes of airmass that influence North America? How do these change between summer and winter?
- maritime polar, continental polar, maritime tropical, arctic, continental tropical.
- from winter to summer=maritime polar, continental polar move out and maritime tropical move in (north)
Describe how cold, warm, and occluded fronts form, what they look like on a weather map, and what weather conditions are associated with each.
- cold=cooler, more dense air into warmer more moist air
- warm=warmer, less dense, air into cooler, more dense air
- occluded=cold front into a warm front
What is a midlatitude cyclone? Which direction do midlatitude cyclones move and circulate?
- a cyclone is any circulation around low pressure (counterclockwise in N. hemisphere)
- move west-east pushed by the jet stream
How old is the earth? Oldest rocks? Most landforms?
- 4.6 billion years
- oldest rock= 3.8-4.28 billion years
- most landforms formed during quaternary, last 1.8 million years
What is the difference between an atom, element, mineral, and rock?
- element= substance that can’t be broken into any other substances by ordinary chemical means
- atom=smallest particle of an element that retains the properties of that element
- minerals=a substance that is naturally occurring, nonliving, solid, chemical element or compound of elements. Has a specific chemical composition and an ordered internal structure or arrangement of atoms
What are the most common elements in earth’s crust?
- Oxygen
- silicon
- aluminum
- iron
- calcium
- sodium
- potassium
- magnesium
What are silicate minerals? What are the differences between felsic and mafic silicates?
- united of silicon and oxygen
- felsic=light color, generally less dense, continental)
- mafic=dark color, generally more dense, oceanic
What are the mains zones of earths internal strucure? Which are solid/liquid/plastic?
- core: inner core=solid. outer core= liquid
- mantle=solid but able to flow at very slow rates
- asthenosphere=plastic
- lithosphere=cooler and less dense
What is plate tectonics? How many tectonic plates are there?
- theory that earth’s crust consists of plates that move individually and collectively
- allows us to explain location of mtn ranges, earthquakes, volcanoes and other landforms
- 14+ plates
*What are the different types of plate boundaries and where do they occur?
- convergent
- divergent
- transform
What is subduction?
-an area where two plates of crust collide and the denser oceanic crust dives beneath the less dense continental plate, forming deep oceanic trenches and seismically active regions
Where is the oldest and youngest oceanic crust?
-
Mid-ocean ridges?
a long, seismically active submarine ridge system situated in the middle of an ocean basin and marking the site of the upwelling of magma associated with seafloor spreading.
Rift valleys (diverence)?
a large elongated depression with steep walls formed by the downward displacement of a block of the earth’s surface between nearly parallel faults or fault systems.
What are hot spots?
-a point of upwelling material originating in the asthenosphere and tending to remain fixed relative to migrating plates(e.g. yellowstone)
Igneous, sedimentary, metamorphic rocks… what is different about how they form? What are some common rock types from each?
- igneous= from magma/lava; crystallize from molten rock material
- sedimentary= from sediment and chemical precipitation from seawater
- metamorphic= from other rocks that recrystallize under high pressure and/or temp
Igneous intrusive vs igneous extrusive rocks…what is different about how they form and their appearance?
- igneous intrusive(plutonic)=rocks crystallize as molten magma cools at depth within the crust or mantle
- igneous extrusive(volcanic)=rocks solidify from lava at the earth’s surface often after a volcanic eruption
Sedimentary rocks.. how do they form? What are their steps involved in their formation?
- are formed at or near the earth’s surface by:
1. weathering of pre-existing rock
2. transportation of sediment
3. sorting and rounding of sediment grains
4. deposition of sediment in layers
5. chemical deposition (precipitation)
6. lithification into solid rocks
Clastic vs chemical vs organic sedimentary rocks…know the difference and an example of each.
- clastic sediment = from weathering and erosion of rock or mineral fragments. (sandstone)
- chemical sediment=from solution and mineral precipitates (limestone)
- organic sediment= from carbon-based organic matter= (coal)
Metamorphic rocks…know how and where they form and a few examples?
-metamorphic rocks= have undergone changes in texture and/or mineralogy through heat, pressure, and chemically active fluids (shale->slate->schist; limestone->marble; sandstone->quartzite)
Topography vs relief?
- topography=the configuration of the earth’s surface
- relief= a difference in election
Continental shields?
-generally an old, low-elevation heartland of region of continental crust; various cartons and ancient mtns exposed at the surface
How does new crust form?
- residual mtns and stable continental cratons
- tectonic mtns and landforms
- volcanic features
How are mtns built?
-orogeny=mtn building event
What are the three types of orogenesis?
- oceanic-continental
- oceanic-oceanic
- continental-continental
new crustal formation and accretion of existing material?
-
Normal vs reverse vs strike-slip faults? (what sort of strain and surface expression do you see with each?
-normal=tensional stress and pull away (apart and up and down)
reverse=compressional stress (push together and together from up and down)
Folding (anticlines and synclines)? what sort of strain and surface expression do you see with each?
- anticline=upfolded strata in which layers slope away from the axis of the fold, or central ridge
- syncline=a trough in oflded strata, with beds that slope toward the axis of the down fold
Earthquakes? Where and why? Epicenter, focus, fault rupture, stick-slip behavior?
- buildup of stress and stored strain energy as plates move relative to one another
- stick-slip behavior
- seismic energy real eased during fault rupture
- focus/hypocenter (point of rupture)
- epicenter (surface)
Shield volcano?
-a symmetrical mtn landform built from effusive eruptions that is gently sloped, gradually rising from the surrounding landscape to a summit crater and typical of the hawaiian islands
Composite volcano?
-a volcano formed by a sequence of explosive volcanic eruptions
Cinder cone?
-a landform of tephra and scoria, usually small and cone-shaped and generally not more than 450 m in height, with a truncated top
Effusive?
- mafic magma
- lower viscosity
- volatiles espace easily
- shield volcanoes, oceanic ridges, hot spots
Explosive?
- felsic magma
- higher viscosity
- volatiles trapped
- compsite volcanoes, subduction zones
Relationship between composition, viscosity, shape, and behavior?
-
What is landmass denudation?
- wearing down of Earth’s surface
- reduces elevation and relief of landforms
- consists of
1. weathering
2. erosion
3. transport
4. deposition
Physical weathering vs chemical weathering?
- physical= rock is broken into smaller pieces, no chemical change
- chemical= chemical changes within rock weaken rock structure
What are four types of each: physical weathering and chemical weathering.
- physical= frost wedging, salt wedging, biological, exfoliation
- chemical= dissolution of carbs, hydrolysis, oxidation, biological
What is karst?
-a distinctive topography formed in a region of chemically weathered limestone with poorly developed surface drainage and solution features that appear pitted and bumpy.
What is differential weathering?
-different rocks are more or less resistant to weathering
What is mass wasting?
- colluvial processes-downslope movement of soil/rock driven by gravity
- slope failure occurs when gravitational force acting on a slope exceeds its resisting force
Different types of mass wasting and the difference among them?
- creep/solifluction
- -movement of individual particles downslope, very slow, dry/wet or freeze/thaw cycles
- slides
- -entire unit moves as a whole, moderately wet and fast
- flows
- -material moves as a liquid, very wet, moderately to very fast
- falls
- -free-falling objects, fast
