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  • General

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  • 对流层

     

    A person walking on cracked salt flats and another person on a snowy mountain.
     

    What if we took a field trip to the troposphere?
    ::如果我们去对流层实地考察呢?

    A  field trip  to the troposphere could start below  sea level  in Badwater  Basin  in Death  Valley . It could end at the top of Mt. Everest at 29,029 feet (8,848m). In other words, every human activity that's in air is in the troposphere. You might say that your life is a field trip to the troposphere!
    ::在死亡谷的巴德水流域,对流层的实地考察可能开始于海平面以下,可能结束于珠穆朗玛峰顶部29,029英尺(8,848米)。换句话说,空气中的每一人类活动都在对流层中。你可能会说,你的生命就是对流层的实地访问!

    Troposphere
    ::活动圈

    The  troposphere  is the lowest layer of the  atmosphere . All of the air you breathe is in the troposphere. All of Earth's weather— wind ,  rain , and snow—occurs in the troposphere.  Most   exist in the troposphere as well, though there are rare types of clouds that exist in higher layers.
    ::对流层是大气层的最低层,您呼吸的所有空气都在对流层中,地球的所有天气——风、雨和对流层中的积雪——都存在于对流层中,大部分也存在于对流层中,尽管在对流层中存在很少类型的云。

    Properties of the Troposphere
    ::活动圈的属性

    The troposphere is the shortest layer of the atmosphere. It rises to only about 12 kilometers (7 miles) above the surface. Even so, this layer holds 75% of all the gas molecules in the atmosphere. That’s because the air is densest in this layer.
    ::对流层是大气中最短的层层。 它仅升至表层上方约12公里(7英里 ) 。 即使如此,这个层也拥有大气中所有气体分子的75%。 这是因为空气在层中密度最高。

    In the troposphere,   decreases with  altitude . The troposphere gets some of its  heat  directly from the  . Most, however, comes from Earth's surface. The surface is heated by the Sun. Some of that heat radiates back into the air. This makes the temperature higher near the surface than at higher altitudes.
    ::在对流层中,对流层会随着高度下降。对流层会直接从地球表面获得部分热量。然而,大部分热量来自地球表面。表层会受到太阳的加热。其中一些热量会回升到空气中。这样,对流层附近的温度会比高海拔时高。

    Mixing of Air
    ::空气混合

    Air in the troposphere is warmer closer to Earth’s surface. Warm air is less dense than cool air, so it rises higher in the troposphere. This starts a  convection cell .  Convection  mixes the air in the troposphere. Rising air is also a main cause of  . All of Earth’s weather takes place in the troposphere.
    ::对流层中的空气更靠近地球表面。温暖的空气比冷空气密度小,因此在对流层中上升。这引发了对流细胞。对流层中的空气混合。对流层中的空气也成为主要原因之一。地球的所有天气都发生在对流层中。

    Temperature Inversion
    ::温度转换

    Sometimes air doesn’t mix in the troposphere. This happens when air is cooler close to the ground than it is above. The cool air is dense, so it stays near the ground. This is called a temperature  inversion  ( Figure  ). An inversion can trap air pollution near the surface. Temperature inversions are more common in the winter. Can you explain why?
    ::有时空气不会在对流层中混合。 当空气靠近地面比地面更冷的时候,这种情况就会发生。 冷空气密度很大,所以它会留在地面附近。 这叫做温度反向( 图表 ) 。 反向可以将空气污染困在地表附近。 冬季温度反向比较常见。 你能解释为什么吗?

    Temperature inversion and its impact on air quality.
     
    Temperature Inversion and Air Pollution. How does a temperature inversion affect air quality?

    Tropopause
    ::特罗波

    At the top of the troposphere is a thin layer of air called the tropopause. This layer acts as a barrier. It prevents cool air in the troposphere from mixing with warm air in the  .
    ::对流层的顶部是一层薄薄的空气,叫做对流层。该层起到屏障的作用。它防止对流层的冷空气与对流层的热空气混合。

    Summary
    ::摘要

    • In the troposphere, warm air ordinarily sits below cooler air.
      ::在对流层中,温暖的空气通常处于冷却空气之下。
    • With a temperature inversion, cold air sits below warm air. This traps the cold air because it cannot rise into the warm air.
      ::随着温度的反向变化,寒冷的空气处于温暖的空气之下,它困住了寒冷的空气,因为它不能升到温暖的空气中。
    • An inversion starts over land at night or in the winter, or near the coast.
      ::变种始于夜间或冬季的陆地上, 或海岸附近。

    Review
    ::回顾

    1. Why is the troposphere the most important layer of the atmosphere?
      ::为什么对流层是大气层最重要的层?
    1. What is the source of heat in the troposphere?
      ::对流层的热源是什么?
    1. Describe the temperature gradient found in the troposphere.
      ::描述对流层中发现的温度梯度。