Transcript Mountains
Factors which influence climate Today’s Aim 1. To learn the how mountains affect climate. Keywords Latitude, Equator, Altitude. How Mountains that affect CLIMATE Brainstorm the factors which you think Mountains affect climate in your journal– discuss with people around you. Mountains SPI 0507.8.2 Explain how mountains affect weather and climate. Three Ways In this PowerPoint you are going to study three ways mountains affect climate. – Elevation – Rain Shadows – Mountain and Valley Breezes How Mountains Affect Weather & Climate Number 1 - Elevation Have you ever noticed as you are driving into what happens when you drive up a mountain? What is the difference between climate and weather? What is climate? 1 Climate • Climate is the pattern of weather that occurs in an area over many years. It determines the types of plants or animals that can survive, and it influences how people live. • Climate is determined by averaging the weather of a region over a long period of time, such as 30 years. What is climate? 1 Latitude and Climate • Latitude, a measure of distance north or south of the equator, affects climate. • The tropics—the region between latitudes 23.5°N and 23.5°S— receive the most solar radiation because the Sun shines almost directly over these areas. What is climate? 1 Latitude and Climate • The polar zones extend from 66.5°N and 66.5°S latitude to the poles. Solar radiation hits these zones at a low angle, spreading energy over a large area. • Polar regions are never warm. What is climate? 1 Latitude and Climate • Between the tropics and the polar zones are the temperate zones. Temperatures here are moderate. Most of the United States is in a temperate zone. How many times have you seen snow on the top of mountains when there was none in the city below? The reason for this is the elevation. Mountain City has the highest elevation of any city in Tennessee at 2350 feet above sea level. The highest point in Johnson County is Snake Mountain at an elevation of 5574 feet above sea level. Elevation The higher the elevation, the lower the temperature becomes. The rate at which the temperature drops is known as the lapse rate. On average, the lapse rate is 3.6 degrees per 1,000 feet. Elevation Differences With Snake Mountain over 2000 feet higher in elevation than Mountain City, the temperature on top of Snake Mountain could easily be 7 degrees cooler. How Mountains Affect Weather & Climate Number 2 - Rain Shadows What is climate? 1 Mountains • At the same latitude, the climate is colder in the mountains than at sea level. • When radiation from the Sun is absorbed by Earth’s surface, it heats the land. What is climate? 1 Mountains • Heat from Earth then warms the atmosphere. • Because Earth’s atmosphere gets thinner at higher altitudes, the air in the mountains has fewer molecules to absorb heat. What is climate? 1 Rain Shadows • On the windward side of a mountain range, air rises, cools, and drops its moisture. • On the leeward side of a mountain range air descends, heats up, and dries the land. Windward Vs. Leeward • Rainfall occurs on the windward side of the mountain where the air is rising. • Cool & Wet • It is dry on the leeward side of the mountain where the air is sinking. • Warm & Dry Rain Shadows Mountains greatly affect the climate. They act as barriers blocking rain and wind. What do you think a rain shadow is? One side of the mountain may have a very different climate from the other side. In some cases mountains create a shadow. This is where rain does not fall. Deserts can form in the rain shadow regions. Animations http://www.mhhe.com/biosci/genbio/tlw3/ eBridge/Chp29/animations/ch29/rain_sha dow_formation.swf http://bio1100b.nicerweb.com/med/Vid/Di scover2e/ch39a04_RainShadow.swf http://www.uky.edu/AS/Geology/howell/g oodies/elearning/module07swf.swf http://www.mrphome.net/mrp/rainshado w.swf Example – Rain Shadow Death Valley in the United States is behind the Pacific Coast Ranges of California and the Sierra Nevada range.