Physical geography: exam 2
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Created by:
love2laugh93 on February 8, 2012
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145 terms
Terms | Definitions |
|---|---|
 Troposphere | Lowest layer Most active zone Majority of nonmarine living organisms Where weather happens Temperature decreases with increasing altitude |
| Tropopause | the upper limit of the Troposphere Higher over the Equator Lower over the poles |
| Mesosphere | Immediately above the Stratopause Coldest of all layers Temperature decreases with increasing altitude |
| Mesopause | the upper limit of the Mesosphere |
| Thermosphere | Uppermost layer Gases are sorted into a variety of sublayers based on molecular mass Temperature increases with increasing altitude Intense solar reactions cause molecules to vibrate at very high speeds creating kinetic energy |
| Intense solar reactions cause.. | molecules to vibrate at very high speeds creating kinetic energy |
| Kinetic Energy | the energy of motion of molecules and is measured as temperature |
| Atmospheric Temperature | a measure of kinetic energy within a unit of space in the air |
| Surface Temperature | a measure of kinetic energy contained in a region very close to Earth's surface |
| Three temperature scales | Fahrenheit, Celsius, Kelvin |
| Wind Chill Index | Calculated using: Actual air temperature, wind speed, and heat loss theory Higher wind speed, the lower wind chill |
| Heat Index | Measures apparent temperature using:Actual air temperature and relative humidity Higher humidity, the higher heat index |
| Influences of Air Temperature: Latitude | Differences in the angle of incidence cause energy to be directed in smaller or larger surface areas Results in distinct temperature differences Low latitudes vs. high latitudes |
| Influences of Air Temperature: Seasons and Length of Day | Axial tilt and migration of subsolar point Influences net radiation between hemispheres Influences day length and daily radiation patterns |
| Influences of Air Temperature: Time of day | Sun arc across the sky: Sunrise, solar noon, and sunset Temporal Lag between highest Sun angle and warmest temperature |
| Maritime places are located.. | within or near a very large body of water |
| Continental places are surrounded by | landmasses |
| Maritime Effect | Water heats more slowly, storing energy Radiation penetrates to lower depths Heated water mixes with cooler water Evaporation transfers energy to atmosphere |
| Continental Effect | Land heats quickly, not storing any energy Radiation does not penetrate surface No mixing of heated and cooled land Low evaporation rates |
| Temperature increase associated with cities, result of urban surfaces: | Darker surfaces have lower albedo and high sensible heat Less forest cover means more energy is conducted raising temperature Less water on surface and not able to moderate temperature Additional heat is generated from human energy use as electricity for air conditioning and lighting |
| Altitude | Temperature decreases with increased elevation |
| Position of topographic barriers | Topographic barriers, like mountain ranges, influence cooling or warming of air that traverse them |
| Windflow patterns | Direction of windflow can change air temperature depending on source of air, its modification, and barriers |
| Hypothetical Continent | Surrounded by ocean Straddles the Equator Isotherms indicate the combined effect of: Maritime/Continental effects Seasonality |
| Air Pressure | the measured weight of air as it exerts pressure on Earth's surface |
| Air pressure decreases.. | with increasing altitude |
| Air density is greatest.. | near the Earth's surface |
| Warm air results in.. | lower air pressure |
| Cooler air results in.. | higher air pressure |
| Measuring Air Pressure | Barometer |
| Mapping Air Pressure | Air pressure changes with altitude |
| High-Pressure System | A circulating body of air that exerts relatively high pressure as air sinks toward the surface Air flow diverges |
| Low-Pressure System | A circulating body of air where relatively less pressure is created as air rises away from the surface Air flow converges |
| Advection | the process by which air flows horizontally from high-pressure to low-pressure |
| Map of Atmospheric Pressure | Isobars indicate the geographic patterns of pressure systems Red arrows illustrate the path of air flow relative to pressure systems |
| Wind direction | Winds are named for the direction they originate (Northerlies, Easterlies, Southerlies, Westerlies) |
| Unequal Heating of Land Surfaces | Variation in the amount of solar radiation received by latitude Air density and pressure differ from place to place Surface air flows from high to low pressure to balance the difference |
| Convection | causes motion in the atmosphere |
| Air flows from.. | areas of high pressure to low pressure |
| Pressure gradient | The greater the difference in pressure, the steeper the gradient The steeper the gradient, the faster the air flow |
| The Direction of Air Flow: Coriolis Force | Due to Earth's rotation Deflects objects traveling in the atmosphere Earth's eastward rotation below Northern Hemisphere, deflection is to the right Southern Hemisphere, deflection is to the left |
| Frictional Forces | Occurs at ground level Strongest at surface, diminishing at about 1500 m (5000 ft) Causes wind to slow down and move in irregular ways |
| Convection Loops | spiraling descending and rising air are linked horizontally by advection |
| Global Pressure and Atmospheric Circulation | Simplified system on an Earth that is nonrotating, untilted, and has a uniform surface |
| Hadley Cell | the tropical convection loop Air at tropics is warmed by year-round direct sunlight |
| Intertropical Convergence Zone (ITCZ) | Warming creates a zone of low pressure at Equator as air rises into the atmosphere Winds converge into ITCZ by advection |
| Subtropical High (STH) Pressure System | Air rising from ITCZ eventually sinks at subtropics creating zones of high pressure Dry and warm winds diverge from STH |
| Ferrel Cell | the circulatory loop that mixes cool polar air with warm tropical air |
| Polar Front | the line of contact between contrasting air masses at about 60 degrees N/S |
| Polar Jet Stream | formed by high-altitude winds that are formed with the temperature/pressure gradient |
| Rossby Waves | develop as undulations in the polar front moderate significant temperature difference on either side |
| Polar Cell | the circulatory loop in the polar regions |
| Polar High Pressure System | Air flowing northward from midlatitudes sinks, producing a weak high-pressure system Consists of masses of rotating, descending dry air that flows toward the polar front |
| Trade Winds --> | ITCZ |
| STH --> | Westerlies and Trade Winds |
| Westerlies and Polar Easterlies--> | Polar Front |
| Polar High--> | Polar Easterlies |
| ITCZ migrates.. | with subsolar point, as the zone of most intense radiation and warming |
| All large pressure systems migrate.. | seasonally due to the consistent distance between them |
| Seasonal shift of the ITCZ and prevailing wind direction in the subtropics | ... |
| Asian monsoons: winter | ITCZ in south; cold air, high pressure |
| Asian monsoons: summer | ITCZ in north; warm air, low pressure |
| Sea breeze | Breeze blows from high-pressure sea to low-pressure sea |
| Land breeze | Breeze blows from high-pressure land to low-pressure sea |
| Valley breeze | Breeze blows upslope as mountain slopes heat up |
| Mountain breeze | Breeze blows downslope as mountain slopes cool off |
| Katabatic winds | Extremely cold, dense air flows downslope under force of gravity. Flows at great speeds |
| Chinook winds | Occur when a steep pressure gradient develops in mountainous regions -high pressure on windward side -low pressure on leeward side |
| surface currents are driven by.. | winds as energy transfers by friction |
| Gyres form as.. | continents block the movement of water |
| Oceanic Conveyor Belt | Slow vertical mix of water between layers of the ocean |
| (OCB) Downwelling currents: | caused by high-density water that is cooler and saltier |
| (OCB) Upwelling currents: | ... |
| El Nino and La Nina | Reversal of "normal" flow of currents and winds in tropical pacific Occurs ever 3-8 years Affects climate -Changes ocean surface temperature -Changes patterns of precipitation |
| Adiabatic Processes | Air cools as it rises and expands. Air warms as is sinks and compresses |
| Dry Adiabatic Lapse Rate | Applies to unsaturated air. Dry air cools or warms at 10 degrees C/1000 m. or 5.5 degrees F/1000 ft. |
| Wet Adiabatic Lapse Rate | Applies to air that reaches the lifting condensation level, or the altitude of saturation. Rate varies with moisture content and temperature. Average rate is about 5 degrees C/1000 m. or 2.7 degrees F/1000 ft. |
| Clouds are.. | visible masses of suspended, minute water droplets or ice crystals |
| Clouds form in.. | regions with high water vapor density |
| Two necessary conditions for cloud formation: | Air must be saturated and must be a substantial quantity of small airborne particles for water vapor to collect on |
| Cloud form | Cirrus, cumulus, and stratus |
| Cloud altitude | High, middle, and low |
| Cirrus clouds | Featherlike; high altitude in the troposphere |
| Stratus clouds | Blanket the sky, overcast; lower part of the atmosphere (fog) |
| Cumulus clouds | Cotton ball appearance; low to mid elevation |
| Cirrocumulus clouds | Pretty high in atmosphere, some amount of puffiness |
| Altocumulus clouds | Mid-level clouds; puffy; blanket the sky |
| Altostratus clouds | Mid-level clouds |
| Cirrostratus clouds | Resemble cirrus, but not quite as featherlike |
| Cumulonimbus | Thunderstorm clouds |
| Stratocumulus | Takes on the appearance of a stratus and cumulus cloud |
| Contrails | created by exhaust from airplanes |
| Fog | (Stratus clouds) Condensing of water vapor close to the ground Burns off when cool air forming fog warms above the dew-point as the day progresses |
| Radiation fog | develops at night when air cools to the dew-point and is held below a temperature inversion, or an overlying body of warmer air |
| Advection fog (Sea fog) | develops when warm air flows over a cooler surface, cooling it to the dew-point |
| Precipitation | Forms within clouds when droplets or ice crystals grow and fall to Earth |
| Rain | unfrozen water droplets |
| Snow | ice crystals |
| Sleet | rain freezes before hitting the ground |
| Freezing rain | rain freezes on impact with the ground |
| Hail | ice crystals that melt and refreeze before falling |
| H2O molecule | combination of 1 oxygen with 2 hydrogens -Positive charge at O -Negative charge at H2 |
| Hydrogen Bonding | Attraction between the hydrogen atoms of water molecules; explains water's physical states |
| Water absorbs and releases.. | latent heat |
| When water changes physical states, energy is.. | either absorbed or released: melting, freezing, evaporation, condensation, sublimation, deposition |
| The Hydrologic Cycle | Movement of water between various storage locations; amount of water is finite; total amount evaporated equals the total precipitated globally |
| Humidity | refers to the concentration of water vapor in the air |
| Maximum humidity | Maximum amount of water vapor that a body of air can hold; warm air can hold more water vapor than cold air |
| Saturation | the point where the air cannot hold any more water vapor at its current temperature |
| Saturation curve | describes the relationship between maximum humidity and temperature |
| Maximum humidity rises with... | temperature |
| Specific humidity | How much water vapor is actually in the air |
| Relative humidity | Ratio of specific humidity to maximum humidity; how close the air is to saturation at its current temperature |
| Lower latitudes | Specific humidity is high Relative humidity is low |
| Higher latitudes | Specific humidity is low Relative humidity is high |
| Diurnal Cycle | Max humidity increases with warming; specific humidity is constant; relative humidity gradually decreases |
| Dew-point temperature | Temperature at which a mass of air is saturated; related to changes in relative or specific humidity: When a body of air cools to point of saturation, it is 100% relative humidity |
| Evaporation | Transformation of liquid water into water vapor |
| Transpiration | results in evaporation directly from leaf pores in plants into the atmosphere |
| All precipitation occurs when... | an air mass rises sufficiently high to condense large quantities of water |
| Four types of lifting: | Convectional uplift, orographic uplift, frontal uplift, convergent uplift |
| Orographic uplift | Airflow interrupted by a mountain range |
| Windward side | Air cools at DALR to dew-point; forms clouds that cool at WALR and precipitation follows |
| Leeward side | Air descends downslope, warming at DALR; creates rain shadow of dry conditions |
| Convectional uplift | Unequal heating of Earth's surfaces |
| Stability of air: | the potential for convection |
| Stable air | little convection and no precipitation |
| Unstable air | strong convection bubbles lift and create precipitation |
| Air mass | a large body of the lower atmosphere with uniform conditions of temperature and moisture |
| Air mass source regions | any large body of land or water where air derives its characteristics |
| Air mass is categorized by.. | Moisture content: c = continental (dry), m = maritime (moist) Latitude (temperature): A = Arctic or Antarctic, P = Polar (50-60 degrees N/S) |
| Fronts | Boundaries between differing air masses; when one air mass advances in a front, frontal uplift causes clouds and/or precipitation |
| Warm front | Warm air advances; warm air slowly lifted |
| Cold front | Cold air advances; warm air rapidly lifted |
| Midlatitude Cyclones | A well-organized low-pressure system that migrates across a region while it spins |
| Midlatitude Cyclones: Upper Air Flow | 500 mb upper air-pressure surface; occurs at a specific but varying altitude over and given place on Earth; vertically divides atmosphere in two |
| Cyclogenesis | the processes forming midlatitude cyclones |
| Cumulus stage | Begins with convection or advancing cold front into mT air; rapid rising air forms cumulus clouds |
| Developing Stage | Condensation releases latent heat |
| Mature Stage | Very unstable air with development of strong updrafts; intense precipitation brings cold air down to create downdrafts |
| Dissipation Stage | ... |
| Production of lightning | Collisions among ice crystals and rain droplets cause difference in electrical charge within clouds |
| (Lightning) Ground has... | positive charge (+) |
| (Lightning) Clouds have... | positive charge (+) at top and negative charge (-) at base |
| In strong storms... | leader (-) from cloud meets streamer (+) from ground, creating "spark" as cloud-to-ground lightning |
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