为什么越往高越冷？

随着我们爬升到山顶或进入高海拔地区，我们会意识到一个普遍的现象：温度开始骤降。这是因为地球的大气层在高空变得更稀薄，进而影响了温度分布。让我们来探索一下为什么越往高越冷。

首先，让我们了解大气层的结构。大气层可以分为四个主要层：对流层、平流层、中间层和热层。对流层是我们所处的最底层，它的厚度约为10公里。在对流层中，温度通常随着高度的增加而减少，这就是我们所说的“递减率”。这是因为大气层受到地表的加热作用，所以离地面越远，温度就越低。

其次，随着我们上升到平流层，情况开始发生变化。平流层位于对流层之上，高度约为45公里以上。在这个层次上，温度开始增加，这是因为平流层吸收了太阳辐射并将其转化为热能。这被称为“臭氧层加热效应”。所以，在海拔较高的地方，我们会感觉到温度开始回暖。

然而，当我们进入中间层时，再次面临冷却的现象。中间层位于海拔约50至85公里之间。这个层次的温度又开始随着高度的增加而下降，这是由于中间层的激发和重新组合反应导致的。在这个层次上，大气层中的分子数量较少，因此无法有效地传递热量，这导致了温度的降低。

最后，我们来到了热层，也被称为外层大气层。热层的高度从85公里开始，延伸至数百公里以上。在这个层次上，温度再次上升，甚至可以达到几千摄氏度。这是由于太阳辐射对大气层分子的极高能量。然而，由于热层的空气非常稀薄，我们几乎感受不到温度的变化。

综上所述，越往高处移动，大气层的密度逐渐变小，从而导致无法有效地传导热能。因此，温度随着高度的增加而下降。这就是为什么越往高处越冷的原因。

Why does it get colder as we go higher?

As we climb to the mountain top or enter high-altitude areas, we realize a common phenomenon: the temperature starts dropping rapidly. This is due to the fact that Earth's atmosphere becomes thinner at higher altitudes, affecting temperature distribution. Let's explore why it gets colder as we go higher.

Firstly, let's understand the structure of the atmosphere. The atmosphere can be divided into four main layers: the troposphere, stratosphere, mesosphere, and thermosphere. The troposphere is the lowest layer where we reside, with a thickness of about 10 kilometers. In the troposphere, temperature generally decreases with increasing altitude, which is known as the "lapse rate." This is because the atmosphere is heated by the Earth's surface, so the farther away from the ground, the lower the temperature.

Secondly, as we ascend to the stratosphere, things start to change. The stratosphere lies above the troposphere and extends to approximately 45 kilometers. In this layer, the temperature begins to increase due to the stratosphere absorbing solar radiation and converting it into heat. This is known as the "ozone heating effect." Therefore, in high-altitude areas, we may feel the temperature starting to warm up.

However, when we enter the mesosphere, we once again encounter cooling. The mesosphere lies between roughly 50 and 85 kilometers in altitude. Here, the temperature decreases again with increasing altitude due to excited and recombination reactions in the mesosphere. With fewer molecules in the atmosphere at this level, heat transfer is less efficient, resulting in temperature decrease.

Lastly, we reach the thermosphere, also known as the outermost atmospheric layer. The thermosphere starts above 85 kilometers and extends to several hundred kilometers or more. In this layer, the temperature increases once again, reaching several thousand degrees Celsius. This is due to the extremely high-energy solar radiation absorbed by atmospheric molecules. However, since the air in the thermosphere is extremely rarefied, we hardly perceive any change in temperature.

In conclusion, as we move higher, the density of the atmosphere gradually decreases, leading to inefficient heat transfer. Therefore, the temperature decreases with increasing altitude. That's why it gets colder as we go higher.