Meteorology Today, Ahrens Chap 8 Flashcards
What does a millibar describe
atmospheric pressure, equal to 100 pascals
What is Hg describe
inches of mercury, describes atmospheric pressure
What is a pascal
is the force of 1 newton acting on a surface area of 1 square
meter.
what are hectopascals
equal to 1 millibar or 100 pascals, used more commonly than millibars
Rate at which atmospheric pressure decreases with elevation
10 millibars per 100 meters
What are contour lines
LInes that connect points of equal elevation
Southern and Northern parts of the US have very different elevations for the same pressure, tell me how
Northern air is colder, lower altitude needed to reach certain pressures and Southern Air is warmer, higher altitudes needed to reach certain pressures
What are ridges on pressure maps
elongated highs of pressure, where air is warm
What are troughs on pressure maps
elongated lows of pressure, where air is cold
How to calculate pressure gradient force
difference in pressure / distance
Direction of pressure gradient force
higher-lower at right angles to the isobars
3 forces that determine wind
pressure gradient force, coriolis force, and friction
If the pressure gradient force were the only force controlling wind, how would it look
wind goes directly from high to low pressures
Coriolis force in comparison to wind speed
Faster the wind, the more the deflection
direction coriolis force acts
right angles
How does wind aloft blow
parallel to isobars, as the coriolis effect deflects it to a right angle. this only occurs with wind aloft, as there is no friction acting upon it
What is geostrophic winds
wind that blows parallel to isobars
what direction does the wind blow in cyclones in the northern and southern
Counterclockwise northern and Clockwise southern
what direction does the wind blow in anticyclones in the northern and southern
Clockwise northern and Counterclockwise southern
why does surface wind not flow like geostrophic wind
friction with the ground causes wind speed to reduce and the coriolis effect to diminish