PLANET EARTH From Pole to Pole

It's now becoming clear that great whites migrate thousands of miles across the oceans to harvest seasonal abundances in different seas. The sun, beating down on tropical waters, powers the weather systems of the globe. Moisture evaporates（moisture本身表示潮湿，这里意译为海水，evaporate表示蒸发的意思） from the warming ocean and rises to create great storms.



The winds generated out at sea sweep inland across the continents. As they travel across the Sahara they create the biggest of all sand storms blowing sand halfway round the world to fertilize the Amazon jungle. Winds blowing across the Indian Ocean collect moisture and sweep northwards towards the Himalayas.



As the air rises, so it cools. The water it carries condenses into clouds and then falls as the life giving rains of the monsoon（季风）. So air currents powered by the sun carry wet air to the middle of continents. Without water there can be no life, but its distribution over the land is far from even. Deserts cover one third of the land's surface and they're growing bigger every year.