Geol 1350: Test 3
57 Cards in this Set
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What are the forces that influence the winds
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pressure gradient force
coriolis force
centrifugal force
frictional force
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what determines the magnitude of Coriolis Force
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V is the wind speed and f is the coriolis parameter
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what is the apparent force of CF due to
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it is due to the rotation of the earth
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For CF what does the magnitude depend on
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it depends on latitude and the speed of the air parcel
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If the latitude is the, the Coriolis force will be
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larger
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what is the Coriolis force at the equator and at the pole
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zero, maximum
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The CF causes a parcel to deflect in which direction in the northern hemisphere
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it causes the parcel to deflect right of its intended path
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The CF causes a parcel to deflect in which direction in the southern hemisphere
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it causes the parcel to deflect left of its intended path in the southern hemisphere
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what is the only thing CF can influence
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CF only influences wind direction, no effect on wind speed
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what is the equation for the magnitude of Centrifugal Force
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CENTF= mV2/R
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what does the m stand for
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mass
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what does the R stand for
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the radius of curvature of the path
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what does the V stand for
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V is the speed of the air parcel
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what is the direction of Centrifugal Force
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pointing away from the center of the curve
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If it has a faster spped and tighter curve of the path traveled (small R), what happens to the centrifugal force
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the centrifugal force is larger
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What does the frictional drag of the ground do to the wind
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The frictional drag of the ground slows wind down
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what is the equation for Frictional Force
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FF=-kV
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what is the magnitude of FF depend on
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it depends on V and K
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what does k stand for
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the roughness of the earth's surface
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what is the direction of Frictional Force
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it always acts in the direction opposite to the movement of teh air parcel (-)
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where is FF important
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in the friction layer (planetary boundary layer)
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For FF where is the lowest level for atmosphere
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1000m
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what is the Geostrophic Balance
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it is the most fundamental horizontal force balance when the pressure gradient force is counter balanced by the CF
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what is the equation for Geostrophic balance
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PGF+CF=0
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what is the resulting wind of Geostrophic balance called
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Geostrophic Wind
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what is the Geostrophic wind good for
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it is a good approximation to winds above earth's surface
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what is the gradient wind
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it is the flow around a curved path where there are three forces involved in the balance (gradient balance)
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what are the three forces involved with the gradient balance
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pressure gradient force
CF
Centrifugal Force
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what is the equation for gradient balance
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PGF+CF+CENTF=0
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when is the gradient balance important
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it is important near high or low pressure centers
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what are the scales of motion
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microscale
mesoscale
synoptic scale
planetary scale
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where does microscale happen
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meters to 1km
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what happens in a microscale
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turbulent eddies
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how long do eddies last
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lifetimes of minutes
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what range is the mesoscale
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1 km to 200 km
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what is contained in the mesoscale
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local winds and circulations
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what is contained in local winds and circulations
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land/sea breezes, mountain/ valley winds, thunderstorms, tornadoes
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what is the lifetime for the mesoscale
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hours to a day
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what is the range for a synoptic scale
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200 km to 2000 km
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what is contained in the synoptic scale
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hurricanes, tropical storms, lows and highs, fronts, everyday weather
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what is the lifetime for synoptic scales
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days to weeks
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what is the planetary scale
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above 2000 km
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what is contained in a planetary scale
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longwaves in westerlies
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what is the lifetime of planetary scales
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weeks
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what is the forces used for microscale
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pressure gradient force, centrifugal force, and FF are important. CF is negligible
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what are the forces used in the mesoscale
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CF becomes more important at the large end of this category
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what is the forces used in the synoptic scale
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the Geostrophic balance between pressure gradient force and CF is dominant
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what is the force for the Global-scale
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Geostrophic balance dominates
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which heats more quickly land or water
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Land which creates temperature differences along the coastline
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what creates a sea breeze
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the temperature difference that drives air to flow from the ocean towards land
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when is the temperature lower over land
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at night
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what causes the land to have a lower temperature at night
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radiative cooling of the land surface
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what produces a land breeze circulation
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the pressure difference with high pressure over land
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what does a land breeze circulation cause
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air flowing towards ocean near the surface and return flow aloft
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what are the primary cause of the General Circulation
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unequal heating of the earth's surface
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what does the unequal heating of the earth's surface cause
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tempertaure gradients---pressure gradients- winds
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what are the two thermal direct cells
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Hadley and Polar
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Geol 1350: Test 3