Structure and Composition of the Present-Day Atmosphere - Air Pollution and Global Warming: History, Science, and Solutions - page 71

3.7. Summary
In this chapter, the structure and composition of the
present-day atmosphere were discussed. Air pressure,
density, and temperature are interrelated by the equation
of state. Pressure and density decrease exponentially
with increasing altitude throughout the atmosphere.
Temperature decreases with increasing altitude in the
troposphere and mesosphere but increases with increas-
ing altitude in the stratosphere and thermosphere. The
temperature is affected by energy transfer processes,
including conduction, convection, advection, and radia-
tion. The troposphere is divided into the boundary layer
and background troposphere. The daytime boundary
layer is often characterized by a surface layer, a con-
vective mixed layer, and an elevated inversion layer.
The nighttime boundary layer is often characterized by
asurface layer, a nocturnal boundary layer, a residual
layer, and an elevated inversion layer. Pollutants emitted
from the surface are initially confined to the boundary
layer. Total air pressure consists of the sum of the partial
pressure of each gas in the air. The air consist of well-
mixed gases, such as molecular nitrogen, molecular
oxygen, and argon, and spatially and temporally vary-
ing gases, such as water vapor, carbon dioxide, methane,
ozone, and nitric oxide. Some spatially and temporally
varying gases have adverse health effects; others affect
radiation transfer through the air. Most are chemically
reactive.

3.6. If temperatures in the middle of the sun are 15 mil-
lion K and those on the Earth are near 300 K, what is the
relative ratio of the thermal speed of a hydrogen atom
in the middle of the sun to that on the Earth? (Assume
the mass of one hydrogen atom is 1.66

10 − 27 kg
molec − 1 .) What are the actual speeds in both cases?
How long would a hydrogen atom take to travel from
the center of the sun to the Earth if it could escape the
sun and if no energy losses occurred during its journey?
3.7. Do convection, conduction, or advection occur in
the moon's atmosphere? Why or why not?

×

3.8. In the absence of an elevated inversion layer in
Figure 3.4a, do you expect pollutant concentrations to
build up or decrease? Why?

3.9. Why does the lower part of the daytime convective
mixed layer lose its buoyancy at night? How does the
loss of buoyancy in this region affect concentrations of
pollutants emitted at night?

3.10. Why are the coldest temperatures in the low-
est 50 km on Earth generally at the tropical tropo-
pause?

3.11. Why does the tropopause height decrease with
increasing latitude?

3.12. According to the equation of state, if temperature
increases with increasing height and pressure decreases
with increasing height in the stratosphere, how must
density change with increasing height?

3.8. Problems
3.1. How tall must a column of liquid water with a
density of 1,000 kg m − 3

10 12 molec cm − 3 3.13. If N q = 1.5 × for ozone gas,

T 980 hPa, find the volume mixing

ratio and partial pressure of ozone.

= 285 K, and p d =

be to balance an atmospheric

pressure of 1,000 hPa?

3.14. If carbon dioxide were not removed from the
oceans by shell production and sedimentation, what
would happen to its atmospheric mixing ratios?

3.2. What do the balloon of Charles and an air parcel
experiencing free convection have in common?

3.15. When the carbon dioxide mixing ratio in the
atmosphere increases, what happens to the concentra-
tion of dissolved carbon dioxide in the ocean?

3.3. Calculate the conductive heat flux through 1 cm
of clay soil if the temperature at the top of the soil is
283 K and that at the bottom is 284 K. How does this
flux compare with the fluxes from Example 3.3?

3.16. Show and explain a possible chemical weath-
ering process between carbon dioxide and magnesite
[MgCO 3 (s)].
3.17. Explain why the volume mixing ratio of oxy-
gen is constant but its number concentration decreases
exponentially with altitude in the bottom 100 km of the
atmosphere.

3.4. If T 295 K at 1 mm above the ground and the

conductive heat flux is H c =

=

250 W m − 2 ,estimate the

air temperature at the ground.

3.5. If oxygen, nitrogen, and ozone did not absorb UV
radiation, what would you expect the temperature pro-
file in the atmosphere to look like between the surface
and top of the thermosphere?

3.18. Calculate the percent reduction in CO 2 (g)