66 Mountain Winds-Mid

Mountain Winds FOCUS Question How do mountains help create wind?

山风焦点问题山是如何帮助产生风的?

Air on the Move Whoosh! Hold on to your hat! Wind can seem as if it comes out of nowhere. But it doesn't just happen Wind is moving air. You can't see it, but you can feel it. Air begins to move when sunlight warms Earth's surface. The air above the warming surface heats up and rises into the atmosphere. That's because warm air. is lighter than cold air High in the sky, the air cools down and begins to sink. The sinking cold air is replaced by more warm air rising up from the ground. This up-and-down motion of warm and cool air creates a cycle of moving air that we experience as wind.

空气在移动呼!抓紧你的帽子!风似乎不知道从哪里冒出来的。 但它不是凭空发生的风是流动的空气。 你看不见它，但你能感觉到它。 当阳光使地球表面变暖时，空气开始流动。 升温表面上方的空气升温并上升到大气中。 那是因为温暖的空气。在高空，空气冷却下来并开始下沉。 下沉的冷空气被从地面上升的暖空气所取代。 这种冷暖空气的上下运动形成了一个循环，我们称之为风。

Mountain Wind Landforms on Earth's surface, such as mountains, also play a role in how wind forms. For example, strong winds can move up a mountain slope and blast down the other side. One reason that mountains create wind is because of their height. The air at the top of a tall mountain is cooler than the air near the base. These differences in air temperature on a mountain help get wind moving. Do You Know? For every 305 meters (1,000 ft.) of elevation a person climbs up a mountain, the temperature drops by 3°C (5.5°F).

地球表面的地貌，如山脉，也在风的形成中发挥着作用。 例如，强风可以沿着山坡向上移动，并从另一侧吹下来。 山脉产生风的一个原因是它们的高度。 高山顶部的空气比山脚附近的空气冷。 山上空气温度的这些差异有助于风的移动。 你知道吗?海拔每上升305米(1000英尺)，气温就会下降3摄氏度(5.5华氏度)。

Up the Mountain Air that moves up the side of a mountain is called upslope wind. This type of wind happens during the day when sunlight warms a mountain slope. The air just above the slope gets warmer and lighter than the air farther up the mountainside. The warm air moves up the slope toward the cool summit. This upslope air motion is also called anabatic (an-uh-BA-tik) wind. If you have hiked up a mountain, you may have felt anabatic wind "pushing" you up the trail.

从山的一侧向上移动的空气被称为上坡风。 这种类型的风发生在白天，当阳光温暖山坡时。 山坡上方的空气比山坡上方的空气更温暖、更轻。 暖空气沿着斜坡向凉爽的山顶移动。 这种上坡的气流运动也被称为anabatic风。 如果你爬上了一座山，你可能会感觉到一阵风把你推上了小径。

Down the Mountain Air moving down the side of a mountain is called a downslope wind. When the air on a mountain slope is colder than the air near the base of the mountain, it sinks. Downslope wind often happens at night as mountain slopes cool down. The colder the air, the faster it sinks and the stronger the wind. Katabatic (kat-uh-BA-tik) wind is a type of downslope wind common in Antarctica and Greenland. Icy mountain slopes chill the air just above them. The cold heavier air quickly sinks down the mountain, resulting in strong, cold wind Brrr!

从山的一侧向下移动的空气被称为下坡风。 当山坡上的空气比山脚附近的空气更冷时，它就会下沉。 下坡风通常发生在夜间，因为山坡降温。 空气越冷，下沉的速度就越快，风力也就越大。 Katabatic (kat-uh-BA-tik)风是南极洲和格陵兰岛常见的一种下坡风。 冰雪覆盖的山坡使山上的空气变得寒冷。 较重的冷空气迅速从山上下沉，形成了强烈的冷风!

Downslope Damage Sometimes downslope winds cause a lot of damage to towns that are near mountains. Gravity helps pull the heavy, cold air down the mountain. Downslope winds can develop into strong windstorms. Boulder is a town in Colorado near the Rocky Mountains. This town has had downslope winds blow at 160 kilometers (99 mi.) per hour. Winds that strong can rip roofs from buildings and shatter windows. They can topple trees and even flip parked motor homes.

有时下坡风会对靠近山区的城镇造成很大的破坏。 重力帮助把沉重的冷空气拉下山。 下坡风可以发展成强风暴。 博尔德是科罗拉多州落基山脉附近的一个城镇。 这个小镇的下坡风以每小时160公里(99英里)的速度肆虐。 那么强的风可以掀翻建筑物的屋顶，打碎窗户。 它们可以推倒树木，甚至掀翻停在路边的房车。