63 The Cryosphere-Mid

The Cryosphere FOCUS Question What is the cryosphere, and why is it important to Earth?

冰冻圈焦点问题冰冻圈是什么，为什么它对地球很重要?

Welcome to the Iceworld The blue planet. The watery planet. The blue marble. Earth has earned these nicknames because it's covered by so much water, but most of it is salty ocean water. Only about 3 percent is fresh water. Surprisingly, most of that fresh water is locked up as solid ice. Welcome to the icy cryosphere (KRY-oh-sfeer)— all the different types of frozen water on Earth. Its main components are glaciers, snow cover, floating ice, and permafrost. Bundle up and let's explore this iceworld. Word Wise The word cryosphere comes from the Greek language. Kryos- means "cold" and -sphere relates to Earth's round shape.

欢迎来到冰世界蓝色星球。 水行星。蓝色弹珠。 地球之所以有这些绰号，是因为它被如此多的水覆盖，但大部分是咸水。 只有3%是淡水。 令人惊讶的是，大部分淡水都以固态冰的形式存在。 欢迎来到冰冻圈(KRY-oh-sfeer)——地球上所有不同类型的冰冻水。 它的主要组成部分是冰川、积雪、浮冰和永久冻土。 穿上衣服，让我们去探索这个冰雪世界吧。 冰冻圈这个词来自希腊语。 Kryos-意思是“冷的”，球体与地球的圆形有关。

Glaciers What rules the cryosphere? Glaciers! These icy giants are by far the main component of the cryosphere. Glaciers are slow-moving masses of ice and snow that occur in some of the coldest places on Earth. They are found in the Arctic region near the North Pole, in the Antarctic region near the South Pole, and high up in some mountains around the globe. Ice sheets are a type of glacier that cover large areas of land near the poles. Another type of glacier is the alpine glacier. These glaciers form in low spots in and around mountains worldwide. Wowser! Ice can be ancient. Some glacial ice covering Antarctica has been there for almost a million years.

是什么统治着冰冻圈? 冰川!到目前为止，这些冰巨人是冰冻圈的主要组成部分。 冰川是缓慢移动的冰和雪，出现在地球上一些最寒冷的地方。 它们分布在北极附近的北极地区，南极附近的南极地区，以及全球一些高山中。 冰原是冰川的一种，覆盖在两极附近的大片土地上。 另一种冰川是高山冰川。 这些冰川形成于世界各地山脉内部和周围的低洼处。 老古板!冰可以是古老的。 一些覆盖在南极洲的冰川已经存在了近100万年。

Snow Cover Have you ever built a snowman or gone sledding? If so you know snow—the softer side of the cryosphere. Snow is a form of frozen precipitation that covers the ground in polar and other cold regions during winter. When the air cools to below freezing—0°C (32°F)— water droplets in clouds form ice crystals called snowflakes. If the ground is also below freezing, falling snow can build up and cover the surface. Unlike glaciers, snow cover is temporary, forming when it's cold and melting when it's warm. Snowmelt contributes to the flowing water in streams and rivers.

你曾经堆过雪人或玩过雪橇吗? 如果是这样，你就知道雪——冰冻圈中较柔软的一面。 雪是一种冰冻降水，在冬季覆盖在极地和其他寒冷地区的地面上。 当空气冷却到零下0°C(32°F)时，云中的水滴会形成称为雪花的冰晶。 如果地面也低于冰点，飘落的雪会堆积起来，覆盖表面。 与冰川不同，积雪是暂时的，寒冷时形成，温暖时融化。 融雪有助于溪水和河流的流动。

Floating Ice You can't ice-skate or play ice hockey without large areas of flat ice. In bodies of water, ice floats and stays at the surface because it is less dense than liquid water. Most of Earth's floating ice. is frozen ocean water called sea ice Sea ice forms near the poles when salty ocean water freezes. Sea ice covers a vast area of Earth's surface—more than twice the size of Canada. Icebergs are chunks of floating ice that form when pieces of glaciers near a coast break off and fall into the ocean. Unlike sea ice, icebergs are made of fresh water. Floating ice also forms in lakes and rivers when the top layers of fresh water freeze in winter.

如果没有大面积的平坦冰面，你就不能滑冰或打冰球。 在水体中，冰漂浮并停留在表面，因为它的密度小于液态水。 地球上大部分的浮冰。 当含盐的海水结冰时，在两极附近就形成了海冰。 海冰覆盖了地球表面的大片区域，面积是加拿大的两倍多。 冰山是当海岸附近的冰川脱落并落入海洋时形成的大块浮冰。 与海冰不同，冰山是由淡水构成的。 当冬季淡水的顶层结冰时，湖泊和河流中也会形成浮冰。

Permafrost Did you ever notice that the ground gets firmer when the temperature drops? When the weather is warm, liquid water fills up tiny spaces in the soil. When the temperature drops, the water freezes and so does the ground. The ground usually thaws in summer. But in places that don't have warm weather, the ground stays frozen all year long. Ground that is permanently frozen— or frozen for at least two years—is called permafrost. Permafrost is only a small part of the cryosphere. Yet almost one-quarter of Earth's exposed ground contains permafrost. You can find it on high mountains, like the Rockies, and in the Arctic and Antarctic.

你有没有注意到，当温度下降时，地面会变得更坚实? 天气暖和时，液态水会填满土壤中的微小空间。 当气温下降时，水结冰，地面也结冰。 夏天地面通常解冻。 但在气候不温暖的地方，地面终年冰冻。 永久冻结或冻结至少两年的地面被称为永久冻土。 永久冻土只是冰冻圈的一小部分。 然而，地球上近四分之一的裸露地面含有永久冻土。 你可以在高山上找到它，比如落基山脉，在北极和南极。