1. Absolute radiative forcings and lifetimes of some atmospheric gases are given below:
|
Gas
|
Absolute Radiative Forcing, W m-2 kg-1
|
Τ, y
|
|
CO2
|
2 × 10-15
|
150
|
|
CH4
|
4 × 10-14
|
14.5
|
|
N2O
|
5 × 10-13
|
120
|
|
HCFC-225ca
|
5 × 10-12
|
2.5
|
|
HFC-134a
|
1 × 10-11
|
1.4
|
|
C2F6
|
2 × 10-11
|
10,000
|
(a) Plot radiative forcing (Wm-2kg-1) versus time for these five gases from 1 to 1000 years. Use a log scale on both axes.
(b) Plot integrated radiative forcing (Wm-2kg-1 y) versus time from 1 to 1000 years. Use a log plot on both axes.
(c) Plot the Global Warming Potential (GWP) of these gases (relative to CO2) versus time from 1 to 1000 years. Use a log plot on both axes.
(d) Comment on these plots.
2. Oxidation of SO2 to H2SO4 can occur via a surface catalyzed process. Under some conditions, the rate of this process is limited by the rate at which SO2 molecules adsorb to the surface of aerosol particles, and the process stops when the surface becomes completely covered by H2SO4 molecules. Assume one H2SO4 molecule covers 30 square Angstroms, and determine the total concentration of sulphate (expressed as μg S per m3 of air) under the following two sets of conditions:
|
|
A
|
B
|
|
Aerosol particle concentration (cm-3)
|
106
|
103
|
|
Average particle diameter (mm)
|
0.1
|
1.0
|
3. The following data were collected for an atmospheric dust sample:
|
Diameter Interval (mm)
|
% of Particles (by mass)
|
|
7-17.5
|
10
|
|
17.5-21
|
10
|
|
21-25
|
10
|
|
25-28
|
10
|
|
28-3-
|
10
|
|
30-33
|
10
|
|
33-36
|
10
|
|
36-41
|
10
|
|
41-49
|
10
|
|
49-70
|
10
|
Plot the frequency distribution of these particles versus diameter by (a) number of particles; (b) surface area and (c) mass. Use linear axes. Assume the particles have ρ= 1.60 g cm-3