Download Weather Quiz Study Guide

Weather Quiz
Study Guide
1. Name two reasons the troposphere is important to us? Troposphere provides pressure,
oxygen, and most weather occurs in the troposphere.
2. Why does Earth have weather? Earth is unequally heated. Earth is always warm at the
equator and cold at the poles creating different densities and thus pressure. Air then
moves from high to low pressure causing wind.
3. Why is Earth unequally heated? The Sun’s rays are most direct in the tropics making it
hotter and become less direct as you move away from the tropics which makes it
colder.
4. From where does nearly all of Earth’s energy come? Sun
5. What happens to the density of air as it is heated? Why? As air is heated it becomes less
dense because the molecules in the air move faster and farther apart. When the
molecules move farther apart, there is less mass in the same amount of volume and the
density decreases.
6. What is a convection cell? Draw a diagram showing convection and show the most likely
position of cloud formation. A convection cell is the circulation set up by unequal heating
of the Earth. Warm, less dense air is pushed upward by colder more dense air.
7. Why are clouds often found above Low pressure storm systems located at the surface?
Rising air causes low pressure to form at the surface. Rising air expands and cools
causing water vapor to condense, forming liquid cloud droplets.
8. Why do few clouds form above surface High pressure?
Sinking air causes high pressure to form at the surface. Sinking air compresses and
warms causing liquid cloud droplets to vaporize, making the cloud disappear.
9. What is the most abundant gas in Earth’s atmosphere? Nitrogen 78%, Oxygen 21%, other
gases including water vapor and carbon dioxide make up 1%
10. Why is air pressure the greatest at the bottom of the troposphere? What instrument is used to
measure air pressure? We live at the bottom of an ocean of air. The weight of all the air
above the ground is pushing on us causing us to feel a pressure of 14.7 lbs. per square
inch of surface area. A barometer is used to measure air pressure.
11. What happens to a barometer reading as you rise up through the troposphere? As you move
upward through the atmosphere there is less and less air above you to push in on you.
Therefore, the air pressure becomes less and less until you reach the vacuum of outer
space (pressure is 0).
12. How is a barometer used to identify an approaching storm system? The barometer shows
the pressure is falling as the storm approaches.
13. How is a barometer used to indicate a storm system moving away from an area?
The barometer shows the pressure is rising as the storm moves away.
14. What do we call the air moving from an area of higher pressure to an area of lower pressure
(***as it always does***)? Air always moves from higher to lower pressure and the
movement is called wind.
15. What is the Coriolis effect and which way are winds turned in the Northern Hemisphere?
The Coriolis effect is the apparent turning of the wind caused by Earth’s rotation. Winds
are “turned” to the right in the Northern Hemisphere.
16. Use arrows to draw the air circulation around the High and Low pressure systems as seen in
the Northern Hemisphere.
H
L
17. How is the direction of a wind named? The wind is named by the direction it comes from.
18. From where does a southerly breeze blow? It blows from the south.
19. When isobars on a surface map are close together in an area, what can you deduce (tell)
about the wind speed in that area? Isobars that are close together show a large pressure
change that causes a high wind speed.
20. Why does weather generally move from west to east in Oregon, WI? We live in prevailing
westerly winds—the jet stream blows from west to east.
21. Four basic types of air masses influence the United States. Label the air mass source
regions on the map below using the appropriate air mass name (cP, mP, cT, or mT) that
develops over each region.
22. What type of front is formed when a cold air mass pushes a warm air mass? When a warm air
mass pushes a cold air mass? Cold front, warm front
23. Draw the symbols that represent the following fronts: a) cold front b) warm front c) stationary
front d) occluded front.
a)
b)
c)
d)
24. From where do cold dry air masses (cP) that influence Wisconsin come? Central Canada
25. From where do warm moist air masses (mT) that influence Wisconsin come? Gulf of Mexico
26. How do fronts produce clouds and precipitation? Fronts form when warm and cold air
masses come together. Warm, less dense air floats over colder, denser air at the.
When the warm air goes up it cools and water vapor in the air condenses forming
clouds and precipitation.
27. Why are we unable to see water vapor? Your eye can’t see individual water molecules.
28. If pressure is held constant, what must be done to liquid water in order for it to vaporize?
The liquid water must absorb heat.
29. If pressure is held constant, what must be done to water vapor in order for it to condense back
into liquid? The water must release heat (cool down).
30. What is a sling psychrometer used for? Sling psychrometer is used to get dew point
temperature and relative humidity.
31. Why does the wet bulb temperature drop lower than the dry bulb temperature? Water on the
wet bulb absorbs heat from the thermometer and vaporizes, taking heat away from the
thermometer.
32. Will the wet bulb thermometer become colder in 50% relative humidity air at 30 °C or in 70 %
relative humidity air at 30 °C? 50% RH because 50% RH air is drier and this allows more
water molecules to evaporate from the wet bulb thermometer. More evaporation makes
the thermometer colder.
33. What is relative humidity? Relative humidity is a comparison of the water vapor that
exists in the air compared to the amount of water vapor that could exist in the air at a
specific temperature.
34. What does 25% relative humidity mean? 25% of the water vapor that could exist actually
does exist in the air at that temperature.
35. What do we call air that has 100% relative humidity? Saturated
36. Can more water vapor exist in warm air or in cold air? Warm air
37. What will happen to the relative humidity if the amount of water vapor in the air remains
constant while the temperature of the air drops? Less water vapor can exist in cold air so if
you drop the air temperature the relative humidity goes up.
38. What special temperature is reached at 100% relative humidity? Dew point temperature
39. For water, what are the freezing/melting and the boiling points in °C? freezing/melting points
= 0 degrees Celsius, boiling point = 100 degrees Celsius
40. Draw a Low pressure system complete with warm and cold fronts. Indicate the wind direction
and temperature in the three sectors of the storm: ahead of the warm front, ahead of the cold
front, and behind the cold front.
41. On the 500 mb jet stream map below, label any troughs and ridges and indicate where surface
temperatures will be generally colder and warmer. Indicate the likely position of the surface
Low 24 hours from now.
42. On the map above, draw in the circulation of a Cut-off Low. Describe the general weather
conditions under the influence of a Cut-off Low. In a cut-off low it is cool and stormy
43. Describe the general weather conditions expected under the influence of a large ridge in the jet
stream. Warm and fair
44. Describe the general weather conditions expected under the influence of a large trough in the
jet stream. Cold and stormy
45. Describe your favorite type of weather. Then on the map below, draw the surface conditions
(Lows/Highs and isobars) and the 500 mb jet stream features (troughs/ridges) that
demonstrate your favorite weather conditions. Warm sunny weather results from high
surface pressure and a ridge in the jet stream. Storms result from having a storm
system/front in our area and a trough in the jet stream.