Worksheet #20, ATOC 3600, November 7, 2000
NAME: ____________________

1. Given the magnitude of exchanges given in class, what is the residence time of water vapor in the atmosphere. (That is, if no sources of water vapor enter the atmosphere, how long will it take for the sinks of water to deplete the atmosphere?)
The reservoir of water vapor in the atmosphere is 170 Gt. The sinks of water vapor over land and ocean equal 495,000 Gt/yr. So if no sources of water vapor exist, the water vapor of the atmosphere will be depleted in 170 Gt / (495 Gt/yr) = .343 years or 125 days.

2. Calculate the moist static energy of air with temperature of 300oK and specific humidity of 15 g kg-1.
moist static energy = cp*300oK + .015kg H20*lv where lv=2.5e6 J kg-1 and cp=1005 J kg-1 K-1
      = 24344 J per kilogram of air

3. Calculate and compare the residence time of atmospheric carbon, free oxygen, and water vapor. The total atmospheric reservoirs of carbon, free oxygen, and water vapor are 750 Gt-C, 1.1 106 Gt-O, and 1.7 105 Gt-H2O, respectively. The rate at which they enter the atmosphere are 50 Gt-C/yr, 200 Gt-O/yr, and 500,000 Gt-H2O/yr.
The residence time is equal to the the reservoir size times the rate at which they enter or leave the atmosphere.
For carbon, residence time = 750 Gt / (50 Gt/yr) or 12 years.
For oxygen, residence time = 1.1x106 Gt / (200 Gt/yr) or 5500 years.
For water, residence time = 1.7x105 Gt / (500,000 Gt/yr) =0.34 year or 124 days.

4. Draw a temperature/pressure diagram of an atmospheric "parcel" moving through the atmosphere during convection. Also show the environment profile. On this diagram, identify the lifting condensation level (LCL), level of free convection (LFC) of the parcel and the area showing CAPE.
see the image from class....basically, the lifting condensation level is the level at which the atmospheric parcel saturates and the level of free convection is the level where the parcel is warmer than the atmosphere. The area on a T-P diagram between the parcel and environment during the part of the ascent when the parcel is warmer than the environment is proportionate to CAPE.

5. If the hydrologic cycle were to become more intense, would it have an impact on the carbon and oxygen cycles. Examine the cycles and identify three process in the carbon and oxygen cycles that you might expect would be impacted by a change in the hydrological cycle.
If the hydrologic cycle were to become more intense, the basic process of dissolution of carbon dioxide in rainwater would probably increase leading to more weathering and dissolution in the oceans. One could also imagine photosynthesis increasing due to increased water availability. Thus two important carbon sinks may be strengthened. Similarly, if photosynthesis increases, the amout of free oxygen in the atmosphere would increase.