Assignment 7 - Atmospheric Moisture and Precipitation

Directions: Please answer the following questions. Where you are asked why, be as complete as possible when answering.

1.  What happens to relative humidity when the water vapor content of the air remains the same, but the temperature decreases?

Why?

2. Based on what you know about relative humidity, what time of the day are plants most likely to wilt if not watered?

Pick an hour and specify am or pm (the correct answer will fall into a range)

3. Which type of fog is most common in Santa Rosa in the Summer and how does it form?

4. Which type of fog is most common in Winter in Sant Rosa, and how does it form?

5. If a container of air at 60°F  with relative humidity of 50% is cooled to 40°F, will the relative humidity increase, decrease or stay the same?

6. I recommend that you draw yourself a diagram of a mountain to help you answer this question.

Answers must be in feet and Farenheit.

Suppose an air mass with an initial temperature of 60°F  is forced to rise over an 8,000 foot mountain. The dew point temperature is 38°F.  Assume a dry adiabatic lapse rate of -5.5°F/1000 ft and a wet adiabatic lapse rate of -3.3°F/1000 ft.

Answer the following questions:

• At what elevation does the relative humidity reach 100%?
• What is the temperature of the air at the top of the mountain (at 8,000 feet)?
• What is the temperature of the air after it descends to sea level on the lee side of the mountain?

7.  Fill in the blanks

The prevailing wind direction for a mountain located at 38°S is ______________.  The dry side of the mountain is which side___________. (north, south, east or west)

The prevailing wind direction for an island at 22° N is ____________. The wet side of the island is which side______.(north, south, east or west)

8.  Using the map below and what you have learned in lectures, which is the "driest continent" and which is the "wettest continent".

Global Annual Average Precipitation Links to an external site.