Quiz #5 Review

• General Circulation
1. Study the handout/extra credit concerning General Circulation. Figure 7.14 is very similar and can be used to fill in the blanks on the handout.
2. Don't forget our simple picture of a low pressure region: Air at the surface converging, rising vertically and at some altitude diverging.  When looking at the low pressure from above the Earth's surface we see the winds blowing counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.  One means of putting all these motions together would be to take your right hand and point your thumb upward to denote the rising air for a low pressure region.  Your fingers now point in the direction of the movement of the air in the horizontal direction (counter-clockwise direction).
3. What does ITCZ stand for?
4. How could you tell where the ITCZ is at any given time using satellite images taken in the IR window region?
5. How could you tell where the Sub-Tropical High Pressure region is at any given time using satellite images taken in the IR water vapor absorption region?
6. How could you tell where the Sub-Tropical High Pressure region is at any given time using satellite images taken in the IR window region?

• Humidity
1. Sketch a simplified version of the hydrologic cycle (this was done in class).
2. Know the daily pattern or cycle of the following: dew point, air temperature, saturation mixing ratio, actual mixing ratio and relative humidity.
3. Know the general geographical pattern of dew point and relative humidity for the U.S. How do the two quantities compare between the east and west coasts?  Where are the regions of highest and lowest values?
4. At saturation, the rate of evaporation is equal to the rate of condensation.  It is at this point that we should see dew form (liquid drops condensing on surfaces such as the bathroom mirror).  Saturation is what we'll want to achieve in order to form clouds, but then the liquid drops of water will be suspended in the air.
5. Pages 85-89 of Ahrens illustrates several different types of fog (some of which seem to be very similar).  In each case saturation is achieved and a cloud is formed.  In this collection of examples there are the three methods of achieving saturation.  What are these three methods?
6. In order to form ice (solid water) from liquid water should one add energy to the water or extract energy?
7. Relative humidity is defined as ___?
8. In what direction is the net energy transported for conditions of; 1) evaporation > condensation, 2) evaporation = condensation, 3) evaporation < condensation.
9. If the RH=50% and the dew point temperature (Td) is 0 C, then what is the air temperature? (Use the definition of RH and the chart on the handout concerning moisture.)
10. What factors influence the rate of evaporation of water?
11. Though it is not included in Chapter 4, Figure 2.2 should be quite familar to you. Especially the bit about which processes need to take energy from the environment and which need to release energy to the environment.
12. If you are told by the Channel 4 meteorologist that the air temperature is 86 F, the saturation mixing ratio is 27.69 g/kg, the dew point is 41 F and the actual mixing ratio is 5.50 g/kg, what is the relative humidity?
13. Would you expect the dew point to be greater in the summer or the winter and why would you expect that?
14. What form of energy transport in the atmosphere is effected by the RH of the air?

a) sensible heat
b) radiation
c) latent heat

• Cloud Types
1. Study the hand-out on Cloud Classification. You should know which clouds belong to the high, middle and low regions of the atmosphere. For example, if you were to fly in a plane at various altitudes what types of clouds might you happen to see?
2. "Sundogs" and Halos are associated with what type of cloud?  See figure 15.16 on page 389 of Ahrens.
3. In what types of clouds could you find both liquid drops and ice crystals.