1. 1 Fog formation
A weather station reports T = 293 K, RH = 50% at sunset. Assuming that P
remains constant, by how much must the temperature drop over the course of
the night in order for fog to form?
1. 2 Phase partitioning of water in cloud
What is the mass concentration of water vapor (g H O2per m of air) in a
liquid-water cloud at a temperature of 273 K? Considering that the liquid water
mass concentration in a cloud ranges typically from 0.1 to 1 g liquid water per m
of air, is most of the water in a cloud present as vapor or as liquid?
1. 3 The ozone layer
Consider the following typical vertical profile of ozone3(O ) number densities
measured over the United States. Ozone is produced in the stratosphere (10-50
km altitude) by photolysis of 2 and subsequent combination of O atoms with
O 2chapter 10). The stratospheric O3layer protects life on Earth by absorbing
solar UV radiation and preventing this radiation from reaching the Earth’s
surface. Fortunately, the O3layer is not in contact with the Earth’s surface;
inhalation of O3is toxic to humans and plants, and the U.S. Environmental
Protection Agency (EPA) has presently an air quality standard of 80 pp3v O not
to be exceeded in surface air.