Lapse Rate Exercise

Insolation & Temperature

Environmental Lapse Rate Exercise

Normal Lapse Rate	3.5 degrees F
Dry Adiabatic Lapse Rate	5.6 degree F
Wet Adiabatic Lapse Rate	3.2 degrees F

Graphic Problem: Fill in the blanks using the lapse rates from the chart above and the word problem using the example.

The "Normal Air Temp" - has no adiabatic cooling effects, so use the Normal Lapse Rate. You are calculating the ambient air temperature for every 1000 feet of change.
The "Rising Air Temp" - where the arrows indicate orographic lifting and compression – does have an adiabatic effect, so use the Dry Adiabatic Rate.
On the second graph showing clouds, note the saturated air and clouds. Therefore, use the Wet Adiabatic Rate only for this section of the graph.
Hint for second graph: because adiabatic lapse rates change with clouds, the beginning and ending temperatures will be different on the other side of the mountain.

Word Problem: Suppose you were standing at 2000 feet elevation and the temperature was 67 degrees Farenheit, then at what elevation would you be standing if it were freezing (32 degrees)?

1) what amount of degrees must you drop to reach freezing?
> 67 - 32 = 35 degrees cooler

2) using the normal lapse rate (3.5 per 1000 feet), how many times does the lapse rate divide into 35 degrees
> 35 degrees of temp change divided by 3.5 (the lapse rate) = 10

3) Now you must convert to feet and add to your base elevation
> (10 x 1000) + 2000 (your base level) = 12,000 feet to reach freezing point

- Try this method using 2000 feet elevation at 63.5 degrees Farenheit;
- what is the freezing point elevation?

- Try this method using 1000 feet elevation at 60 degrees Farenheit;
- what is the freezing point elevation?