英语听力：探索发现 科学新发现：我们的大气层-12（在线收听） |
Our atmosphere is in constant motion; the moving air that causes our weather circulates between the ground and 50,000 feet. It is the sun that drives this movement. When solar energy reaches earth, it heats the surface and atmosphere, but it does so unevenly. This temperature difference causes the air to move. Hot air near the equator expands and rises; cold air at the poles becomes denser and sinks. Noah’s Marty Ralf can track its movement over the globe on the revolutionary science on a sphere simulator. Portrayal
What we are seeing here is a portrayal of the air surface temperature, and red and warm colors are warm temperatures like we see in the tropics here, up in the poles you see the blues and greens, those are the colder surface temperatures. So we can watch this, and actually see the warm air moving northward, the cold air moving southward, and we can see the changes in the seasons.
If the atmosphere didn’t move, the poles would be 45 degrees cooler, and the equator, 25 degrees warmer. The great deserts of the Sahara, Atacama and Mojave would expand dramatically. Northerly cities like London or Boston would be locked in an icy winter. It is only the atmosphere’s circulation that prevents this. It regulates the temperature, moving the air to create the weather that covers our globe. |
| 原文地址：http://www.tingroom.com/lesson/yytltsfx/2014/284452.html |