Weather and Climate - Assignment Example

Question 4: Explain how heat transfer follows the second law of thermodynamics. Answer: According to the second law of thermodynamics, heat flows in response to a temperature gradient. Heat flows from a high-temperature region toward the low-temperature region to remove the existing gradient. Heat is transferred by the processes of conduction, convection, radiation and latent heating (phase transition of water). Question 6: During which phase changes of water are latent heat released to the environment?

Answer: Latent heat is released to the environment during phase transition of water to lower energy states i.e., freezing, condensation and deposition. Question 7: On a global annual average basis, what is the most important process in cooling Earth’s surface? Answer: On a global annual average basis, radiational heating of earth’s surface is greater than radiational cooling and radiational cooling of the atmosphere is greater than radiational heating. However, due to the formation of the temperature gradient, heat is transported from warmer earth’s surface to the cooler atmosphere through processes of latent heating and sensible heating cooling the earth’s surface.

Radiation is the principal means by which heat enters and escapes from the planet to space maintaining a habitable environment on earth. Question 1: A traffic sign along an Ohio highway warns motorists that a bridge freezes before the road surface. Why does the bridge surface freeze first? Answer: If the temperature falls below freezing, the bridge will freeze more quickly than the road surface. Compared to the road surface, the bridge is exposed to air from all sides resulting in rapid heat loss.

Additionally, the heat underneath the road keeps it warm enough extending the time duration of heat loss. The bridge material (mostly steel or concrete) is also a good conductor of heat, whereas road surface material (asphalt) is an insulator of heat. For these reasons, a traffic sign along an Ohio highway warns motorists that a bridge freezes before the road surface. Question 3: Compare the advantages and disadvantages of the Celsius versus Fahrenheit temperature scales for weather observation and forecasting?

Answer: Both Fahrenheit and Celsius are useful temperature scales for measuring temperature and are based upon the reproducible phase changes in water. On the Celsius scale, the freezing point of water is 0°C and the boiling point is 100°C. On the Fahrenheit temperature scale, water freezes at 32°F and boils at 212°F. Thus, the Celsius scale is more convenient to use as a 100-degree interval separates the freezing and boiling points of pure water at sea level. Compared to Celsius, Fahrenheit scale is more precise due to its smaller degrees.

Celsius is used in the metric and Fahrenheit is used in the imperial system of measurement. Question 4: At what air temperature is the reading on the Celsius scale the same as that on the Fahrenheit scale? Answer: Applying temperature conversion formulas for -40°C; °F = 9/5 °C + 32° And, °C = 5/9 (°F - 32°). So, (-40°C x 1.8) + 32 = (-72 + 32) = -40°F Or, (-40°F - 32) / 1.8 = (-72 / 1.8) = -40°C The reading on Celsius and Fahrenheit scale is same at -40 degrees.

Question 7: Air, especially still air, is a poor conductor of heat. Provide some examples of how this property of still air is used to conserve energy for space heating and cooling. Answer: The still air is a poor conductor of heat, so it has very low convection and conduction properties. During winter, energy can be conserved by opening window shades that’ll allow solar radiation inside the house where it can warm floors, furniture, and furnishings. Fiberglass blankets can also help save energy because of the air trapped between their fiberglass elements inhibiting heat loss.

During summer, closing window shades and drapes will keep sun rays out of the house decreasing the overall load on the cooling system. Energy can also be conserved by using ceiling fans instead of central air-conditioning reducing high-temperature degrees. Question 10: How and why would the temperature of an Arctic air mass change as the air mass moves from snow-covered ground to bare ground? Answer: Arctic air mass is a mass of very cold and dry air formed over snow-covered ground. Arctic air moves from the snow-covered colder ground towards the warmer bare ground behind a cold front by the process of cold air advection.

As the Arctic air mass travels over the earth’s surface not covered with snow, it gets warmer from below by sensible heating (conduction and convection). In contrast, the temperature of Arctic air mass will decrease if it travels over a cold, snow-covered surface. Air mass advection may affect the influence of local radiation budget on air temperature.