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118 Cards in this Set
- Front
- Back
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high pressure flows ____________ in northern hemisphere
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clockwise
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high pressure flows ____________ in southern hemisphere
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counter clockwise
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low pressure flows _____________ in n. hemis
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counter clock wise
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low pressure flows ____________ in s. hemis
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clockwise
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which has clouds and precipitation: low or high pressure
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low
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what happens at low pressure? regarding convergence/divergence
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upper air divergence
lower air convergence |
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what happens at high pressure? regarding convergence/divergence
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upper air convergence
lower air divergence |
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Which is stable/unstable out of sinking or rising air
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sinking: stable
rising: unstable |
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what is average surface (sea level) pressure
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1013.2 millibars
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what happens to air pressure as you rise
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decreases ALWAYS
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What millibar chart/feet ASL is half of Earth's air pressure
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500 mb/18,500 ft ASL
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name millibar chart
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850=4000
700=9000 500=18,500 300=30,000 250=34,250 200=38,500 |
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newton's first law of motion
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object remains at rest or in motion at constant velocity
and in straight line as long as no force is exerted |
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newton's second law of motion
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F = MA
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newton's third law of motion
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for every action, theres an equal and opposite reaction
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greater pressure difference is equal to what two things
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greater pressure gradient and greater wind
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what i pressure gradient force
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difference in pressure across surface
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what forces cause winds to blow
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pressure gradient force
coriolis force friction |
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what is coriolis force and what effect does it have on wind
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deflection cause by rotating object
affects direction, not speed |
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where is coriolis effect greatest? least greatest?
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greatest: poles
least greatest: equator |
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amount of deflection depends on
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1. rotation of earth
2. latitude 3. objects speed |
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where is the friction layer/boundary layer?
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2000+ feet above surface
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what is frictions role in wind
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keeps winds in balance
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what is geostrophic wind
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theoretical horizontal wind blowing in straight path, parallel to isobard at constant speed
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what causes geostrophic wind
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exact balance of pressure gradient force and coriolis effect
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where are geostrophic winds found
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upper level wind flow
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what is hydrostatic balance
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vertical, exact balance between vertical pressure gradient force and gravity
lets earths atmosphere remain in place |
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what causes atmosphere to become imbalance
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thunderstorms
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three factors in measuring/determining wind
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speed, gustiness, and direction
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prevailing winds are a ____ wind
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south
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what are wind roses and what do they measure
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rose with petals that shows average wind speed and direction for any given months
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wind vane measure
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wind direction
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anemometer measures
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wind speed
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what two instruments are being replaced
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wind vane and anemometer
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aerovane measures
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wind speed
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rawinsonde measures
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speed and direction
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windsock measures
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speed and direction
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doppler radar measures
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velocity
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atmospheric profilers measures
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wind
speed???? |
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what is a wind shear
what direction are they/can they be? |
rapid change in wind direction or speed in small area of atmosphere
horiz/vert/both |
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what does microscale measure
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campus/town
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mesoscale measures..
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campus/town- several states
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macroscale measures
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several states-north america
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most improved scale in weather forecasting
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mesoscale
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who thought of single atmospheric cell
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George Hadley
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explain single atmomspheric cell
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high pressure at poles, sinks and flows south toward equator, warms and rises back up to poles
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what causes three cell atmospheric system
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coriolis effect deflects air
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what is ITCZ and what does it stand for and where is it located and why
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inter-tropical convergence zone
area of low pressure near equator (doldrums) always north of equator because greater land mass in northern hemisphere |
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where are the zones of subtropical highs
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30 degrees N and S
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what winds are associated with subtropical highs and how do they flow
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trades winds (NE and SE trade winds/horse latitudes)
E to West |
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where are zones of subtropical lows
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60 degrees N and S
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what are zones of subtropical lows called and how do they flow
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Prevailing westerlies
W to E |
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where is HIGH pressure in NORTHERN hemis. in WINTER
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land
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where is HIGH pressure in NORTHERN hemis in SUMMER
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water
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where is HIGH pressure in SOUTHERN hemis in WINTER
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water
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where is HIGH pressure in SOUTHERN hemis in SUMMER
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land
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what are jet streams
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high level ribbons of air
strong upper level STEERING winds |
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what are jet streams' jobs
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reaching thermal equilibrium
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polar jet stream- what does it do and what level is it found
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moves cold air away
200 mb/38,500 ft ASL |
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Subtropical jet stream- what does it do and what level is it found
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moves warm air away
goes ahead of storms systems and serves as a source of moisture for thunderstorms 850-700 mb/4000-9800 ft ASL |
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what is an upwelling
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surface water is removed from shore and replaced by deep colder water
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what is la nina
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colder than average pacific water temp (west of S. america)
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what is el nino
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warmer than average pacific water temp (west of S. america)
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what is el nino's effect on us?
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causes winter to be wetter in south
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what was result of 1982-1983 el nino
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$8 billion in damage
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what was result of 1986-1987 el nino
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ended drought in southeast US
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what was result of 1991-1992 el nino
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ended 5 year drought in cali, severe texas flooding
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when does land breezes occur and explain how it works?
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nighttime
high pressure on land, air sinks, diverges, flows over ocean, warms, rises, cools on land, repeats |
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when do ocean breezes occur and how do they work
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daytime
high pressure over ocean, air sinks, diverges, flows over land, warms, rises, cools over ocean, repeats |
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when does mountain breeze occur and how does it work
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nighttime
low pressure in valley- so warm air from mountain top cools and sinks downslope to valley. warms and rises toward mountain of high pressures, cools and sinks again |
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when does valley breeze occur and how does it work
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daytime
high pressure in valley- so air diverges at valley and rises upslope while warming. sinks down middle toward valley again |
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what is a monsoon
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seasonal wind shift bringing heavy rain
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where are monsoons
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SE Asia and India
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where do winter monsoons form and where is H and L pressure
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forms over land
high pressure on land low pressure on water |
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where do summer monsoons form and where is H and L pressure
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forms over water
low pressure on land high pressure on water |
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monsoon moves from what pressure to what press
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high to low
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what causes baby monsoon in SE USA
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summer thermal lows
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what is a thermal low and what creates it
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low pressure situation created by changes in air temperature
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what is a katabatic wind and what causes it; what is its characteristics and where is it found
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cold downslope wind caused by gravity
destructive greenland and antarctica |
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What is a Chinook wind and where found
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warm downslope wind found in East rockies
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Santa Ana Wind- what is it, where found, and when is it most common
what does it cause to happen |
warm, dry downslope wind found in Cali- fall months (october)
wet winter, dry summer |
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what causes Santa Ana wind
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high pressure over great salt lake basin
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Name two desert winds
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Haboob and Dust Devils
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where are haboobs?
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north africa and india
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what is an Eddy? and what causes it?
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microscale effect cause by friction
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What two characteristics characterize air masses?
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temp and humididty
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what is A or cA air mass and where found/how is it
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continental arctic
colder air, very little moisture |
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what is/describe cP, where found?
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continental polar
not as cold as cA but cold north texas |
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what is/describe mP, where found?
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maritime polar
cold, moist, originates over water Seattle |
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what is/describe mT, where found?
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maritime Tropical
warm, moist, causes t storms Texas |
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what is/describe cT, wehre found?
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continental tropical
forms over sierra madres and SW USA (Arizona/el paso) (n. mexico) |
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How do lakes affect snow
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cold polar air flows from north over great lakes, picks up moisture, causes snow in northern states
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what is a front
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boundary between air masses
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what is frontolysis
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front is dying
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what is frontogenesis
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front is developing
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what is overrunning
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warmer, less dense air is forced to rise over cooler air on ground
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cold front- slope? does anything develop?
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warm air rises above front
steep slope positive (1:50) blue downward arrows clouds develop because of lifting |
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which front is more dynamic? cold or warm front?
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cold
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warm front- slope? anything develop?
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warm air warms from top down
best example of overrunning gentle slope (1:150) negative slope, upward red semi circles |
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stationary front- why does it occur, slope?
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little forward movement of either airmass
upper level winds run parallel to frontal boundary negative slope, upward semi circles, downward triangles |
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occluded front- what happens, slope? where common
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cold front overtakes warm front in vicinity of surface low
common in northern US negative slope, purple semi circles and triangles |
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the dry line
where is it common |
boundary between cT (hot dry air) and mT (warm, moist air) air masses
plain states |
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what happens with cold front meets with tropical air at dry line and why
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major thunderstorms
because weight of CT air is heavier than mT air, dry line scale lift occurs, thunderstorms |
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weather forecasting
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predicting how states of atmosphere will change with time
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what must be known to forecast weather
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current weather information over large area
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which is broad/subset between meteorology and weather forecasting
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broad= meteorology
subset= weather forecasting |
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puzzle pieces of meteorology
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weather radars and satellite images
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geostationary radar
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22,000 above surface, stays in same space
infrared, visible, and water vapor |
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infrared satellite
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measures temps of cloud tops
hotter colors=cooler temps |
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visible satellite
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shows clouds, only visible in day time
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water vapor satellite
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measures water vapor
white means moisture not clouds necessarily |
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polar orbiting satellites
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30,000 feet above surface, run parallel to meridians, passing over north to south poles
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what do weather radars measure and when was it invented
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1957- hydrometeors
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two types of way weather radars measure precipitation
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1. reflectivity data
2. velocity data |
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most reflective hydrometeor?
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wet hail
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green in velocity radar means?
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inbound toward radar
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red in velocity radar means?
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outbound away from radar
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three rules of radars
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cone of silence
with range there is height modes; clear air vs. precipitation |
