Homework for Chapter 4 - Atmospheric Moisture

SHOW ALL WORK , CIRCLE THE CORRECT ANSWER, PLEASE BE NEAT AND STAPLE YOUR HOMEWORK!

ALSO, PLEASE USE A SPREADSHEET FOR ALL GRAPHS

Follow the Problem solving steps discussed in class

1. It can be shown that the saturation vapor pressure (e_s) depends only on temperature:

where e_o = 6.11 hPa and T_o = 273 K are constant parameters. R_v is the gas constant for water vapor and is equal to 461 JK^-1kg^-1. L is the latent heat of evaporation if water is present or the latent heat of deposition if ice is present. T is the temperature in Kelvin

a. For water, create a plot of e_s versus temperature for T=250 K to 273 K. Make sure e_s is on the y axis and temperature is on the x axis.  How does e_s depend on temperature? exp refers to the exponential function.

b.  On the same graph, plot e_s versus temperature for ice.

c.  Is e_s  larger for ice or for water?

2.  Given a parcel of air having a temperature of 35 degrees C and relative humidity of 95% find:

a. saturation vapor pressure

b. vapor pressure 

d.  If the temperature of the air increased to 40 degrees C will the air feel more or less humid?  Explain.

3. Explain how and why each of the following will change as a parcel of air with an unchanging amount of water vapor rises, expands, and cools: (a) absolute humidity; (b) relative humidity; (c) actual vapor pressure; (d) saturation vapor pressure

4. Where in the U.S. would you go to experience the least variation in dew point from January to July?

EXTRA CREDIT: Given two parcels, one is dry containing 78% N2, 21% O2, and 1% AR while the other is moist, containing 78% N2, 21% O2, 0.5% AR, and 0.5% H2O. Show that the dry parcel has a larger density than the moist parcel.