前程百利小编为考生带来托福阅读背景之暴风雨。通过本文让我们了解暴风雨的特点，产生过程等等知识。希望大家可以从中理解并掌握一些专业词汇，同时学习相关背景知识。
The basic science of all storms
All storms have two things in common: low atmospheric pressure at the storm’s center, and winds that are created by the flow of air from higher pressure outside the storm toward the low pressure at the center. Wind, in other words, is air that’s being pushed by high pressure toward low pressure.
Areas of low air pressure occur because the Sun heats the Earth unequally. The Sun shines down almost directly on Earth’s tropical regions near the equator, heating this region more than the polar regions around the North and South poles and the middle latitudes between the poles and the tropics. Storms, along with ocean currents, redistribute heat from the tropics to the middle latitudes and the poles. Without storms and ocean currents, the tropics would grow hotter and hotter until the oceans boiled. In other words, the Sun’s heat powers the weather.
Air pouring into an area of low pressure from all sides rises because it doesn’t have any place else to go. As air rises, it cools, and if it cools enough the water vapor in the air begins to condense. This condensation creates the tiny drops of water or tiny ice crystals that make up clouds. Under the right conditions, the tiny water drops or ice crystals merge to fall from the cloud as larger water drops of rain or ice crystals of snow. This is why storms bring clouds and usually bring rain, snow, or other kinds of ice.
以上就是前程百利小编为大家带来的托福阅读背景，平时的阅读练习是托福考试阅读备考的重要一环。希望大家利用好每份材料，尽可能多地从中获取知识。预祝大家托福考试取得好成绩。预祝大家托福考试取得好成绩!
