# GEOL 1330 Name:

Global Warming

Lab #4 Due Oct. 11

1. (20 points) Go to the online energy balance model available at: http://www.uta.edu/faculty/awinguth/edu_outreach/studentProject/index.html . It calculates Earth’s average temperature in dependence of solar irradiance, Earth’s reflectivity (albedo, a), and Earth’s emissivity. With incoming energy being balanced by outgoing energy, a solar irradiance of 1365 Wm-2, and the global albedo set to 30% (=0.3), the model calculates an average global temperature of 14.69°C (=”Year 0”, please disregard the other years). In the lower right, you can change the values for albedo, irradiance, and emissivity.

Sunspot activity might change the irradiance by about 0.1 %. Assuming that the given irradiance of 1365 Wm-2 is a mean value, by how much does global temperature change if you increase the irradiance by 0.05 % or decrease it by 0.05 %? Please show which values you are using in the model.

By how much does global temperature change if the albedo decreases from 30% to 20% (using 1365 Wm-2 for solar irradiance)?

2. (10 points) Electromagnetic radiation (“light”) travels at a speed of ~3 x 108 m s-1. The distance from Sun to Earth is ~150 x 106 km. How long does radiation from the Sun take to reach Earth? Show your calculation.

3. (20 points) Draw schematically two curves into the figure below, one for the zonally averaged incoming visible short wave (QSW) radiation from the sun (solid curve) and one for the zonally averaged outgoing long-wave infrared (QLW) radiation (dashed curve) from the Earth’s surface depending on latitude. Label the two curves. Point out areas of radiative surplus (+) and deficit (-) on the Earth’s surface. (Hint: You may want to consult Fig. 4.2 in your textbook).

4. (20 points) Draw the major wind directions for the northern and southern hemisphere in the figure below and label the wind belts.

30°S

60°S

30°N

60°N

5. (10 points) Explain where and how deep-water forms in the ocean.

6. (20 points) The figure below shows average annual ocean salinity values. Explain why salinity in the polar regions is lower than that of the subtropical regions around 30 degrees latitude. How do you expect salinity values for polar regions to change during winter and during summer?

Teamwork in the lab is encouraged. However, each student must provide his/her own answer. Copying of answers results in a grade of zero for all students involved.

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