chapter 5 atmospheric circulation and wind systems Flashcards
(39 cards)
barometer
an instrument used to measure air pressure
thermal vs dynamic pressure
thermal- results from changes in temperature
dynamic- caused by air movement
three forces that control wind speed and direction near earths surface
- pressure gradient force
- coriolis force
- friction force
pressure gradient force
the resulting force from changes in barometric pressure across earths surface
isobar
a line drawn on a map connecting points of equal pressure
pressure gradient runs ______ to isobars
perpendicular
coriolis effect
perceived deflection of moving objects in relation to earths surface
coriolis effect: in the northern hemisphere objects veer to the ___. in the southern hemisphere objects veer to the ___.
right
left
friction layer
the area of the atmosphere where wind is slowed by the friction with earths surface
geostrophic winds
fast, high altutude winds that are strongly deflected by the coriolis effect
anemeter
measures wind based on the speed of propeller rotation when exposed to the wind
aerovane
a wind vane and anemometer combined as a single instrument
three ways to portray wind on a map
wind barb
wind vectors
streamlines
cyclone vs anticyclone
cyclone- a region of low pressure with counterclockwise circulation in the northern hemisphere
anticyclone- a region of high pressure with clockwise rotation in the northern hemisphere
ITCZ
a discontinuous band of thermal low pressure and thunderstorms that encircles the planet in the tropics
subtropical high
a discontinuous belt of dynamic high pressure and aridity made up of anticyclones
subpolar low
a discontinuous belt of dynamic low pressure
polar high
an area of cold, dense air at each pole that forms a zone of thermal high pressure
trade winds
easterly surface wins found from the ITCZ to the subtropical high, between 0 and 30 degrees N/S
doldrums
a low wind region near the equator associated with the ITCZ where the trade winds meets
horse latitude
a low wind region centered on 30 degrees n/s
westerlies
surface winds that come from the west and are found in both hemispheres between the subpolar low and the subtropical high
polar easterlies
cold, dry wins originating near both poles and flowing south and east
polar jet stream
a fast ribbon of air that occurs on the boundary of the polar cell and meanders between 45-70 degrees n/s