Quiz2 on Wed. Feb. 15 covers the topics contained in lecture from Wed Jan 25 through Mon. Feb 13, corresponding text readings, GA1, and the Smith, Lemonick, Murray, Eilperin, and Benford articles.

Sample Quiz2 answers:

1- B ("peak" is the wavelength of greatest energy emission, they are the wavelengths corresponding to the "humps"[peaks] that appear in the curves in Fig.4-2)

2- C (along coastlines there might be a small underground flux directly from groundwater to ocean[D], but on a continental scale runoff via rivers/streams dominates in moving water from continents directly to the ocean) Not yet covered in lecture other than GA2 introduction, but see Fig. 5.1 of Mackenzie, where arrows indicate “fluxes”.

3- D

4- E

5- C (along with CO₂, they are the two most important greenhouse gases)

6- B (in the Earth's general global circulation, there are three convection cells in each hemisphere. In those convection cells, air is rising at the Equator (0° latitude) and 60°N and 60°S latitude, and air is sinking at 30°N and 30°S latitude and at both poles (90°S and 90°N). Deserts occur where air is sinking, pressure is high, and cloud formation and precipitation is inhibited)

7- B

8- D (Temperature is a measure of the motion of molecules and atoms. Absolute zero is the lowest possible temperature where that motion is minimal. The Kelvin scale is based on a value of 0 at absolute zero; on the Celsius scale absolute zero is at -273°C, and on the Fahrenheit scale absolute zero is about -460°F. Celsius and Kelvin scales are linked in that a 1-degree increase on the Kelvin scale is identical to a 1- degree increase on the Celsius scale)

9- E (a sink is a mechanism for removal of something; a source is a mechanism for adding something. Photosynthesis would be a source for oxygen in the atmosphere, whereas the reverse photosynthesis reactions for decomposition, combustion, and respiration would all be sinks for atmospheric oxygen)

10- B

11- see clip if you don’t remember

12- C

13- The amount of energy emitted by an object is related to the 4^th power of its temperature (see "Rules of Radiation"). The energy of the object at 6000 degrees would be proportional to its temperature to the 4th power (6000⁴= 6000 to the 4^th power) and that of the 300K object would be 300⁴. The ratio of those 2 would be (6000/300)⁴ = 20⁴ =20x20x20x20 = 160,000. Therefore the object that is 20 times hotter than the other object emits 160,000 times as much energy as the cooler object.

14- Our current detailed definition of the greenhouse effect is that the atmosphere is fairly transparent to most of the wavelengths of solar radiation (there are some important exceptions such as ozone absorbing infrared in the upper atmosphere), but the atmosphere tends to absorb a lot of outgoing terrestrial radiation thereby retaining energy longer in the earth-atmosphere system. Once the solar radiation is absorbed by the Earth's atmosphere and surface, it contributes to the temperatures of the Earth and atmosphere (288K). The Earth and atmosphere re-radiate terrestrial radiation (peak is in infrared) back toward space, but greenhouse gases such as water vapor and carbon dioxide are very effect in absorbing that outgoing long-wavelength radiation thus keeping it in the Earth-atmosphere system much longer than it would be if there were no greenhouse gases present. The presence of this effect has been very important to maintaining Earth's mild conditions for billions of years (Our potential global change problem is the "enhanced greenhouse effect" that is perhaps causing our planet to become warmer).

15- air rises near the equator where solar heating is greatest. At high altitude it moves poleward and then sinks back to surface to provide the return flow to replace the air that rose. Air of the Hadley cell actually falls back toward the Earth’s surface around 30°N and 30°S.

16- without greenhouse effect, Earth’s average temperature would be 33°C colder (T= -18°C) than it presently is; it has maintained mild conditions on the Earth for billions of years despite the reduced intensity of the early sun. It is the “enhanced greenhouse effect” in which the concentration of greenhouse gases is increasing, which we are concerned about in terms of negative consequences for the planet.

17- in many cases, formation of ore deposits is related to processes occurring along plate boundaries. For example, where plates come together (convergent boundary) many different ore deposits of metals are formed as a result of one plate being subducted beneath another and the associated melting and magma formation. Some mineral resources such as Aluminum ore are concentrated because of climate conditions that weather everything away except the aluminum and oxygen.

18- 0-12km (the troposphere) temperature decreases from 15°C at the surface to -58°C at 12km. From 12-50 km (the stratosphere), the temperature increases to about 0°C at 50km.

19. H₂O + CO₂ => CH₂O + O₂, which requires both sunlight and chlorophyll

20- inter-tropical convergence zone (the Earth’s “heat equator”) is where solar heating is most intense and air rises; it shifts location from one season to the next (it shifts north of the geographic equator in our summer).

21- albedo is reflectivity; clouds have high albedo, asphalt has low albedo; read Benford for rest of answer

22- if you have a temperature above absolute zero you will be emitting radiation. Plug your temperature of about 300K into Wien’s Law and find out the peak wavelength of your spectrum- it should be in the infrared.

23- weather represents immediate atmospheric conditions, temperature, humidity, pressure, winds, etc. (current or at some specific time in the past). Climate is weather averaged over several decades (usually at least 3, but some models are comparing 20-year periods at the end of the 20^th Century with the forecast temperature, precipitation, etc at the end of the 21^st Century)

24- CO₂, CH₄, N₂O

25- see Mackenzie book (Fig. 4.9) or p. 81 of this link; winds would be counterclockwise.