8 Flashcards
T/F: we can generally expect the air to be rising above areas of surface low pressure and sinking above areas of surface high pressure.
‘True
Surface winds move ________ From the center of a high pressure area
Outward (diverges)
T/F: Air pressure decreases with height more rapidly in warm air than cold air
False
Which force acts at a 90 degree angle to the wind?
Coriolis force
What is generally associated with troughs on an upper level iso basic chart?
Low pressure center
Another term for isobaric charts is?
Constant pressure chart
A station at an altitude of 900mb (about 3,000 ft) above sea level measure, with an air pressure of 930 mb would have a sea level pressure of?
1020 mb
If upper-level divergence exceeds surface convergence, the air pressure at the center of the surface low will _____?
Decrease
On an isobaric surface, pressure is ____?
Constant
What pressure variation cause air to move from areas of high pressure to areas of low pressure
Horizontal pressure variations
What is the angle at which surface winds cross isobars?
A large degree dependent on the roughness of the terrain
The magnitude of the coriolis force varies with wind speed and?
And latitude
T/F: the Coriolis force is the force that causes wind to blow
FALSE
T/F: The pressure gradient force is non-existent at the equator
False
The change in _____ that occurs over a given horizontal distance is called the pressure gradient
amount of pressure change
The pressure gradient force is directed from higher pressure towards lower pressure at?
All places on earth
A geostrophic wind is a wind that results from a balance between what two forces?
The Coriolis force and the pressure gradient force
What is considered to be standard sea-level atmospheric pressure (in mb)
1013.25 mb
What is the theoretical wind that would result from an exact balance between the Coriolis force and the pressure gradient force ?
Geostrophic flow
Surface winds that blow across isobars at an angle and the pressure gradient force is balanced by the ______ force and the Coriolis force.
Frictional force
What does a ridge indicate on an isobaric chart?
indicates higher than average heights
T/F: an altimeter measures altitude but is calibrated to indicate pressure?
FALSE
Which of the following produces the strongest Coriolis force?
Fast winds and High latitude
The pressure gradient force has a direct effect on ?
Horizontal wind movements
The surface pressure at the bases of warm and cold columns of air are equal. Air pressure in the warm column of air will _______ with increasing height _____________ in the cold column
Decrease, More slowly than,
T/F: Net convergence of air would cause surface pressure to increase and net divergence would cause surface pressure to decrease.
True
Isobaric surfaces are higher or lower in less dense, warm air? Higher or lower in cold more dense air?
Higher, lower
What causes surface winds to move more slowly than winds aloft with the same pressure gradient.
Friction
The Coriolis force is a ________ force created by earths rotation
Apparent force
Upper level winds in the middle latitudes of both hemispheres generally blow from the?
West
T/F: because lows are also known as cyclones, the flow of air around them is often called anticyclonic flow
FALSE
The force that would cause a stationary parcel of air to begin to move horizontally is called?
The pressure gradient force
On a 500 mb chart, contour lines are drawn to represent horizontal changes in ________, which corresponds to horizontal changes in ________.
Altitude, pressure
Warm air aloft is associated with constant pressure surfaces that are found at higher latitudes than normal and higher than normal atmospheric ______ aloft
Pressure
Millibars and hectopascal are commonly found on a surface weather map and are both units of what?
Pressure
A rapid change in pressure over a relatively short distance is called?
A steep pressure gradient
The wind around a surface high pressure center in the northern hemisphere blows ______ and outward from the center
Clockwise
In the middle latitudes, when an area of higher pressure approaches a city, surface pressure usually ____ when it moves away. Pressure usually _______.
Rises,Rises
