Expedition 25 The Subtropics

Expedition 25, The Subtropics. Written by Celeste Fraser.

25号探险之旅：亚热带 作者：塞莱斯特·弗雷泽

Expedition 25. On Expedition 25, we'll explore the world at 25 degrees north and south latitude, written as 25 degrees N and 25 degrees S latitude. On the map above, each of these latitude lines circles Earth about 1 ,725 miles 2 ,775 kilometers north or south of the equator. Even though these latitudes are far apart, the climate at both of them is similar because they are the same distance from the equator. What do you think the climate in these areas is like? Hint, bring plenty of water. You're going to need it.

25号探险之旅。 在本次25号探险中，我们将探索南北纬25度的世界，也就是北纬25°和南纬25°区域。 在上图中，这两条纬度线分别环绕地球，距离赤道南北约1725英里（2775公里）。 虽然这两个纬度相隔很远，但因为它们到赤道的距离相同，所以两地的气候十分相似。 你觉得这些区域的气候会是什么样的呢？ 提示：记得带够充足的水哦。 你肯定会用到它的。

Beyond the tropics. Traveling at 25 degrees north and 25 degrees south latitude, we're just outside the tropical zone or tropics, which is the region of Earth that is closest to the equator. The boundaries of the tropical zone are the Tropic of Cancer at 23 .5 degrees north latitude and the Tropic of Capricorn at 23 .5 degrees south latitude. The regions we'll be traveling to lie in the latitudes just beyond the tropics in the subtropical zone.

热带之外。 沿着南北纬25度前行，我们刚好走出热带，热带就是地球上距离赤道最近的区域。 热带的边界分别是北纬23.5度的北回归线，和南纬23.5度的南回归线。 我们即将前往的区域，就位于热带外侧的亚热带区域。

Recipe for making deserts Unlike the hot, rainy tropical zone near the equator, the subtropics receive very little rain. That's because high pressure in the atmosphere keeps hot, dry air stuck in place over the subtropics. That same high pressure also keeps rainfall in the subtropics to a minimum, less than 10 inches per year in many places. The result of these climate patterns is a predictable band of deserts that circle Earth at these latitudes. Hop in the plane and let's go visit some of them.

沙漠是怎么形成的 赤道附近炎热多雨，而亚热带的降雨量却少得可怜。 这是因为大气中的高气压让干热空气一直停留在亚热带上空。 同样是受高气压影响，亚热带的降雨量极低，很多地方年降雨量还不到10英寸。 这种气候模式最终在这些纬度形成了一条环绕地球的沙漠带。 快登上飞机，我们一起去参观其中几处沙漠吧。

Deserts in the North For hours you've been flying over northern Africa at 25 degrees north latitude. You are over the world's largest desert, the Sahara. The word Sahara means desert in Arabic, the language spoken in much of North Africa. The Sahara is as big as the entire United States. As you look at the desert from high above, you see dunes, huge mountains of sand that look like golden ocean waves. But there are few signs of people.

北半球的沙漠 你已经在北纬25度的北非上空飞行了好几个小时。 你现在正飞越世界上最大的沙漠——撒哈拉沙漠。 "撒哈拉"在阿拉伯语里就是沙漠的意思，阿拉伯语是北非多数地区使用的语言。 撒哈拉沙漠的面积和整个美国一样大。 当你从高空俯瞰这片沙漠，能看到沙丘——巨大的沙山，看起来就像金色的海浪。 但是这里几乎看不到人烟。

Cairo, Egypt. City on the Nile. You land at Cairo, Egypt, located at 30 degrees north latitude. When you step off the plane, the first things you notice are grit in your mouth and the sting of dust in your nose. Sand from the Sahara swirls through the air and covers everything. This big capital city is home to several million people. The Nile River flows through the center of Cairo. It is Egypt's main source of water.

埃及开罗。 尼罗河畔的城市。 你降落在了北纬30度的埃及开罗。 你走下飞机，最先注意到的就是嘴里的沙粒，还有鼻子里灰尘带来的刺痒感。 撒哈拉的沙子在空中飞舞，覆盖了一切。 这座大城市居住着数百万人口。 尼罗河从开罗的中心穿城而过。 它是埃及最主要的水源。