Week 5 Assignment (9/15 - 9/19) -- Hints for the Short Answer Questions: 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 16
 

#1)  Remember that the RH = (amount of water vapor present / amount of water vapor the air can hold at the given temp) X 100

So, as an example, if the air temp is 30 C, (from Table 16.1) the air can hold 26.5 g/kg.  Now, if the actual vapor content is 15 g/kg, then the RH = (15 g/kg  divided by 26.5 g/kg) X 100  = 56.6 %.

#3)  Recall that the dew point temperature is the temperature of the air at saturation, or we could also say that it is the temperature that the air must be cooled to in order for the air to be saturated.  To answer question 3, you must first determine the saturation mixing ratio of the air at the given temperature.  In the case of (a), the air has a temperature of 25 C, therefore (from table 1), the saturation mixing ratio is 20 g/kg.  To determine the dew point temperature of air at 25C and an RH of 50%, you can use the following formula for RH:

RH = the actual mixing ratio of the air / saturation mixing ratio
 

We have been given the RH (= 50%); and we know the saturation mixing ratio (20 g/kg);  we can solve the above equation for the saturation mixing ratio:

We get: actual mixing mixing ratio = RH X saturation mixing ratio

Thus, actual mixing ratio = (.50) X 20 g/kg = 10 g/kg

Now use Table 16.1 to look up the temperature that corresponds to a mixing ratio of 10 g/kg.

#5)  A couple students mentioned that they could not find the link to the map of the U.S.A. dew point statistics.  Here it is:

http://www.ems.psu.edu/wx/usstats/dewpstats.html & here is a link to a map of the USA with temperature statistics

Use the information from these maps to find the dew point and the temperature, then use this information and Table 16.1 to find the saturation mixing ratio and the mixing ratio.  Once you have determined the the mixing ratio and the saturation mixing ratio, you can deterimine the RH, by recalling that the RH = (mixing ratio / saturation mixing ratio) X 100

# 8) You need to determine the dew point temperature of the air (using the given information and Table 16.1).  Then allow the parcel to rise and cool dry adiabatically until it cools to it's dew point temperature (which is when condensation will occur).  Then allow the parcel to continue rising moist adiabatically and determine its temperature at the top of the mountain.

# 13) You'll need to convert mm/day to inches/day.