Rain and Humidity - Assignment Example

Answer: As the saturation vapor pressure varies directly with temperature, the relative humidity varies inversely with temperature. If no water vapor were added to or removed from unsaturated air, the relative humidity increase as the temperature drops and decreases as the temperature rises. That’s why the air temperature usually rises from a minimum during sunrise to a maximum during early to mid-afternoon on a clear calm day. Question 7. Why does the amount of precipitable water vary with the mean temperature of the troposphere?

Answer: The average precipitable water decreases with latitude in response to the pole ward decline in the mean air temperature because evaporation and precipitable water are lower in cold regions. Precipitable water varies from 4.0 cm in the humid tropics to less than 0.5 cm at the Polar Regions. When troposphere in middle and high latitudes is warmest during summer, the amounts of precipitable water are highest. Question 9. Why are clouds and precipitation more likely on the windward slopes of a mountain range than the leeward slopes?

Answer: Air that is forced to ascend the windward slopes expands and cools which increases its relative humidity. On sufficient cooling, saturation is achieved and clouds and precipitation develop.. Question 10. What is the significance of a rain shadow for agriculture? Answer: A rain shadow with semi-arid to arid conditions is considered to be the boundary between dry land and rain-fed agriculture. This climate contrast affects the indigenous plant and animal communities, domestic water supply, demand for irrigation water, types of crops that can be grown, and requirements for human shelter.

Chapter 6, Critical Thinking Questions Question 2. How and why does the moisture content of the top soil affect the maximum air temperature in the lower troposphere? Answer: Solar radiation heats up the ground surface that transfers heat and moisture from top soil to the atmosphere. This heat and moisture transfer between earth’s surface and the atmosphere occurs by sensible heating (conduction and convection). The heated air has much more capacity to hold moisture content than cooler air. The release or absorption of latent heat affects temperature in the lower troposphere.

The ascending humid air currents also expand and cool influencing the surrounding ambient air temperature. The evaporated moisture content from top soils also adds to the green house effect by trapping more infrared radiation. Question 3. In late autumn or early winter, cold air flows on northwest winds from snow-covered ground across the ice-free waters of Lake Superior. Describe the changes in temperature, vapor pressure, and stability of the cold air as it flows over the lake. Answer: In late autumn or early winter, the ice free waters of Lake Superior are warmer compared to the cold air masses flowing from the North West.

When this cold air passes over the lake, the lower levels of the atmosphere take up excessive moisture and heat. The