INTRODUCTORY METEOROLOGY ASSIGNMENT
Q1. a) Why do the tops of cumulus clouds often change from a cauliflower appearance to a more diffuse appearance as the clouds grow?
b) Why would you expect lake effect snow in the northern Great Lakes region to be more frequent in December than it is in February?
c) Why do small droplets of pure water evaporate in air, even when the relative humidity is 100%?
d) Why is the equivalent blackbody temperature of Venus lower than that of the Earth even though Venus is closer to the sun?
e) Why do low clouds emit more infrared radiation than high clouds of comparable thickness?
f) Explain the similarities and difference between the formation of contrails that form behind aircraft and ship-tracks that form behind ships on the ocean.
g) Why is the fraction of incoming solar radiation that is backscattered to space by clouds higher when the sun is low in the sky than when it is directly overhead?
Q2. Over a period that is typically 11 years, the solar irradiance can vary from 1364 W/m2 to 1368 W/m2. Using an Earth radius of 6370 km and a global albedo of 12%, answer the following questions:
(a) If the Earth had no atmosphere, what would be the resulting range of equilibrium surface temperature?
(b) Assume that the Earth has an atmosphere which is semi-transparent to IR radiation, with an emissivity of 85%. Now what is the resulting range of equilibrium surface temperature due to the solar cycle?
Q3. Use the Kohler curve below to determine the fate of newly formed droplets as listed below. State whether the droplet would evaporate completely, grow continuously, or reach a final radius. Mark the figure appropriately.
a) A 0.1 μm droplet of pure water in air with a super-saturation of 0.3%.
b) A 0.2 μm droplet mixed with 10-19 kg of salt NaCl in air with a relative humidity of 95%.
c) A 1 μm droplet mixed with 10-19 kg of ammonium sulfate in air with a relative humidity of 100.2%.
The figure above gives equilibrium RH over droplets of different radius for (1) pure water, (2) 10-19 kg of salt NaCl, (3) 10-18 kg of NaCl, (4) 10-17 kg of NaCl, (5) 10-19 kg of ammonium sulfate (NH4)2SO4, and (6) 10-18 kg of (NH4)2SO4.