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“温室气体”如何让热量,但不让出来?

2018 - 07 - 28 - t09:47:18z

,诚实对我来说没有任何意义。怎么热气体通过一种方式而不是其他?它不像我们的上所以很多门,只能打开一个。对我来说,这似乎悍然不顾一切我一直教物理宇宙是如何工作的。 如果热量可以通过物质的一种方法,没有理由不能通过其他方式。除了明显的“温室气体”。 最接近我所知道的,这种方式是单向的镜子。但这并不具有相同的效果。原因你可以看到通过一方,而不是其他是因为大多数光反射,但不是全部。因此,如果你在一个黑暗的房间,光线从外面进来会压倒小光被反射在房间。 But if you're on the outside, virtually no light is coming through from the dark side and thus you can only see what is being reflected.

In short, it makes no sense to me and flies in the face of everything I've been taught. Now, I'm not a climate change denier. Actually, this is something I just now thought about. I've never really bothered to question it before.

gerrit回答的“温室气体”如何让热量,但不让出来?

2018 - 07 - 28 - t10:18:15z

简而言之: 辐射进入<强> < /强>来自太阳的短波辐射。太阳辐射主要是可见的(以及紫外和近红外辐射波长之间的大部分0.2µm和2µm。这个波长是由太阳的温度,在6000 K的顺序。可见辐射(大约0.4µm和0.7µm)之间,所有的气体在大气中几乎完全透明。云做的散射辐射所以你不能直接看到太阳的时候阴天,但他们仍然让足够的光线通过,所以它仍然是光在一个阴天(不亮),尽管它感到凉爽。 树叶的辐射是<强>长波辐射< / >强,也被称为地面辐射或热辐射(错误地)。对地球而言,这是由辐射的波长大多4µm和40µm之间。这个波长是由地球的温度在290 K左右。在这些波长,温室气体大多是不透明的。他们吸收辐射。再辐射吸收热量的温室气体,但在两个方向(回到地球和大气中较高图层),并在较低的温度。 The upward longwave radiation gets in turn absorbed by higher-up layers of greenhouse gases, et cetera, such that ultimately the layers of greenhouse gases that do radiate into space tend to be high up in the air (say at 240 K). Thus, their overall effect is to radiate less heat into space than the Earth surface would in the absence of those gases.

The most important greenhouse gases are water vapour, carbon dioxide, and methane.

Source: gisgeography.com

Source: science of doom

凯文回答的“温室气体”如何让热量,但不让出来?

2018 - 07 - 29 - t14:41:35z

Gerrit的技术回答;我要回答一个外行。 有两种方法对象失去热量。 < ul > <李>首先,人们最熟悉的方式,传导。摸别的东西,和热材料转移一些热冷材料。这就是为什么你迅速失去热量如果韦德到寒冷的水域:你的身体是热的,水是冷的,所以从你身体的能量渗入水你触摸。李李< / > < >第二,不过,有点难以直观把握:辐射。或者如果它帮助,认为它是光。一切发出辐射/光——这是基于材料有多热。有没有想过为什么每个材料首先加热真的如何开始焕发出红色(烤箱、炉灶、营火余烬等)?这是因为当它热,能量放出足够的能量是在人眼看来,红(频谱能量最低的颜色。) Heat it up further, and the color eventually shifts to a white.

Make sense so far?

Okay, Earth doesn't lose heat to conduction. Simply put, it's in a near-vacuum; there's not really anything its touching to transfer its heat to.

Instead, it loses its energy to radiation.

Now, objects emit radiation based on their temperature. So the energy coming from the sun? It's based on the temperature of the surface of the sun: about 6,000 Kelvin (about 10k degrees F). So the light/energy/radiation coming from it is very high-energy. That energy strikes earth and heats it up. But the Earth itself is comparatively cool: an average of 287 Kelvin (56 degrees F.) So the radiation that earth emits is much lower in energy.

And that's the key. Gasses like Carbon Dioxide don't allow lower-energy radiation to pass as easily has higher-energy radiation. So while it lets a lot of the sun's energy in, it doesn't let the radiated energy back out as easily.

回答为“温室气体”如何让craq热量,但不让出来?

2018 - 07 - 30 - t00:08:49z

添加到Gerrit优秀的答案,我想添加一些图片。图像总是帮助澄清事情对我来说。 首先,这显示了光谱光来自太阳的红色。峰在可见范围*。它也用蓝色显示了地球的热辐射。这是在红外范围。下面,它展示了不同气体允许不同频率的光的传播。有很多,所以现在,只注意二氧化碳的行——最广为人知的温室气体。注意,它允许接近100%传输在可见范围内,但有一个灰色补丁在地球辐射的频率范围。(我添加了一个圆在这个补丁)。< a href = " https://i.stack.imgur.com/WG3sI.png " rel = " noreferrer " > < img src = " https://i.stack.imgur.com/WG3sI.png " alt = "大气传输" > < / > (< a href = " https://commons.wikimedia.org/wiki/File Atmospheric_Transmission.png): rel = " noreferrer " > https://commons.wikimedia.org/wiki/File Atmospheric_Transmission.png] < / > 其次,有这张照片的金属杆加热到“白热化”。 At this temperature it is radiating in the visible range. The hottest part looks yellow-white (~2000K), the medium part looks red (~1000K), and the rest looks black (room temperature, ~300K). So you can see that objects with different temperatures radiate at different wavelengths. [https://commons.wikimedia.org/wiki/File:Blacksmith_working.jpg]

Actually, the black part of the rod is still radiating, but in the infra-red part of the spectrum, which our eyes can't see. You may be familiar with infra-red cameras being used to measure temperature of people, or as a kind of night-vision. So this last picture from an infra-red camera shows that even "cold" objects like people are emitting radiation. [https://en.wikipedia.org/wiki/SGR-A1#/media/File:Thermal_image_-hand-_1.jpg]

So to sum up, the sun is hot (6000K) and emits light, which is mostly in the visible range. Visible light passes through the gases in the atmosphere and heats the earth up to 300K. The earth emits infra-red light which does not pass through Carbon Dioxide. So Carbon Dioxide traps some of the heat which would otherwise have radiated away from Earth. More Carbon Dioxide traps more heat, causing the temperature of the Earth to slowly rise.

*saying "the peak is in the visible range" is the easiest way to understand it, but the causality is round the wrong way. Our eyes evolved to have the highest sensitivity in the range where the sun produced the most light.