The Ecology of Hope

Winter Science Workshop #1: Homework

Due Friday, 1/18/02  (Answer Key)

Taking the Pulse of the Earth & Agents of Climate


1) Distinguish between "climate" and "weather". Explain how all weather is ultimately a consequence of solar energy.

2) What are the four layers of the atmosphere? How are the "boundaries" defined? Propose a hypothesis that explains why the temperature of the troposphere decreases at higher altitude and why that of the stratosphere increases at higher altitude. How might you test this hypothesis?

3) What are clouds? Dry air has a density of about 1.2 kg/m3. Use this information and the information on page 26 to determine approximately what percentage of clouds consist of water. Why are clouds white? What role do they play in the Earth's energy "budget"? What do you think would happen if there were more clouds than currently exist? Under what conditions would more clouds be formed?

4) Construct a water "budget" of the Great Salt Lake: what are the "inflows"; what are the "outflows". How would this compare with a typical freshwater lake, such as Lake Washington or Lake Superior? Does this account for the unusual composition of the lake water? How would the relative sizes of these inflows and outflows vary over the course of a "typical" year? What changed during the mid-1980s to these flows and how did it affect the level of the Lake?

5) How fast are the winds of the jet stream, in miles per hour? (1 hour = 60 minutes; 1 min. = 60 seconds; 1 km = 1000 m; 1 mile = 1.61 km)

6) Approximately how many gallons of water are evaporated from the world's oceans each year? (1 gallon = 3.79 L; 1 L = 1000 cm3; 1 m3 = 106 cm3)

7) Write a mathematical equation that relates precipitation rate, evaporation rate and runoff rate. Explain how Asia can have a higher precipitation rate than South America, yet have a smaller precipitation flux. In North America, approximately what percentage of precipitation reaches the ocean by runoff? What percentage evaporates before reaching the sea?

8) Why is the insurance industry concerned that the amount of ocean water above 27° C (81° F) may increase in the near future?