Explain the distribution of solar heating across Earth. How does it vary? How are these variations balanced?
Earth's heat budget is fueled by the sun's energy. On an average day, about half of the solar energy that reaches the upper atmosphere is absorbed at Earth's surface. This heat is not evenly distributed, however. Sunlight striking polar latitudes spreads over a greater area and reflects back to space more than sunlight striking the tropical latitudes does. This is due to differences in the angle that the sun's rays strike Earth in these areas-the sunlight strikes polar regions at a low angle, and it strikes tropical regions at a near-vertical angle. The tropical regions, therefore, receive more radiation than they re-radiate (or reflect), causing a surplus. The polar regions re-radiate more radiation than they receive, causing a deficit. However, ocean currents and air masses move excess heat from the tropics toward the poles, helping to equalize the heat imbalance. Over long periods of time, the total incoming heat equals the total heat radiating into space, making Earth, as a whole, in thermal equilibrium.
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The ____________________ rate of increase is the rate a population would grow if it had unlimited resources.
Fill in the blank(s) with the appropriate word(s).
For a specific delivered dose of "soft" x-rays, which type of type of material has the largest absorbed dose?
A) bone B) muscle C) water D) They all have the same absorbed dose.
Why is it difficult for tobacco farmers to convert to farming other crop types?
A) Tobacco is a labor intensive crop B) Tobacco farms are small C) Tobacco tends to make the soil unusable for other crops. D) Both A and B E) Both B and C
An air mass exhibiting warm and humid conditions is designated as ____
a. mP b. cT c. mT d. cP