Format

• The second hourly exam will be on Tuesday, October 30 during class.
• The exam will test material discussed in lecture from the last hourly exam.
• Format of the exam will be similar to the 1st hourly.

Material you should know for 2nd hourly exam:

Earth's Energy Budget

1. What is electromagnetic radiation?
2. Know difference between short and longwave radiation
3. What is the wavelength of visible light? (0.4 to 0.7 microns)
4. Be able to calculate max wavelength of emission of Sun using Wein's Law.
5. What is the percentage of energy emitted by the Sun in the UV, VIS, and IR part of the spectrum? (7% UV, 44% VIS, 48% IR)What is the mean temperature of the Earth? (15 deg C or 288 deg K)
6. What is the mean temperature of the Earth without an atmosphere? (-16 to -18 degC)
7. Be able to calculate max wavelength of emission for the Earth using Wein's Law.
8. Solar constant 1370-1380 W/m²
9. Know numbers for the Earth's Energy Budget: for example,
10. How much of the energy reaching the earth is reflected? (about 30%)
11. How much is reflected by air(6%), clouds(20%), and surface(4%)?
12. What percentage of incoming radiation is absorbed by the atmosphere? (19%)
13. What percentage of incoming radiation is absorbed by the Earth surface? (51%)
14. How is the solar spectrum different from outside the Earth's atmosphere to at the Earth's surface (sea level)?

Greenhouse Effect

1. What is the definition of a greenhouse gas?
2. What are the 5 important greenhouse gases in the atmosphere?
3. Know the "present" and "preIndustrial" values for each of the following greenhouse gasses and approximately by how much they increased (see handout):
   • Carbon dioxide
   • Methane
   • Nitrous Oxide
   • CFCs, HCFC, etc (know that pre-Ind is 0 and they were introduced in 1950s)
4. Know the major sources for each of these greenhouse gases?
5. What is radiative forcing? Be familiar with examples of both positive and negative forcings.
6. What is the relative contribution of each greenhouse gas to radiative forcing (see handout)?
7. How much has anthropogenic greenhouse gases increased radiative forcing since Industrial Revolution? 2.66 W/m²
8. How much warming is predicted from 2.66 W/m² increase in radiative forcing according to IPCC? (~1 degC)

Global Warming (as far as we get in this section)

Be sure you have read the IPCC SR4 Summary for Policymakers.

1. What is the IPCC? Why should we regard IPCC's findings as reliable (or not)?
2. How much has global mean temperature risen since 1880? (about 0.6 +/- 0.2 deg C)
3. 1990s was warmest decade on record and 2005 was the hottest year on record
4. The increase in temperature over the past 140 years has not been gradual, rather the increase was greatest from 1910-1945 and 1976-2000
5. Snow cover and ice extent have decreased since late 1960s. Alpine glaciers have been retreating globally.
6. Sea level has been rising during 20th century by 0.1 to 0.2 meters
7. Precipitation has increased during 20th century
8. Be familiar with the various processes that contribute to radiative forcing (both + and -)
9. What have been the role of anthropogenic aerosols on climate?

Energy Budget

The main theme of lab since the 1st hourly exam has been the Earth's Energy Budget. Be familiar with the reservoirs of energy and the fluxes of energy to and from reservoirs. Be able to reproduce the basics of the Stella energy budget models with and without the atmosphere. Understand how the Energy Budget relates to the greenhouse effect and global warming issue.

Greenhouse Gases/Global Warming

Be sure to have read the following readings -- questions related to these readings are likely!

Greenhouse Gas Emissions and Global Warming Potential

IPCC AR4 Summary for Policymakers.