# Tag Info

13

The traditional answer basically comes down to the physics concept of adiabatic cooling, a description of which is: - There is less pressure as you go up in the atmosphere (basically due to less air weighing down) - Air takes up more volume at lower pressures - Since there's nothing else to supply the energy needed to expand, the air employs the energy that ...

11

We had a surprising opportunity to study this very question during the period of September 11-14, 2001, when all air traffic was grounded across the United States. The research was inconclusive, but they found that there was a 1.8 degree celsius increase across the US during this time frame compared to the three days before and after that time frame. ...

11

As you suggest, longer the path, larger the proportion of scattered radiation. Since the shorter wavelengths are more strongly affected by the Rayleigh scattering, sunlight appears more red when the sun is low. Lower solar elevation angle will also result in longer path through the ozone layer, and hence stronger absorption at the UV-B wavelength range. ...

9

Ignoring meteorological factors and any dust or satellites, this is still an incomplete problem. You would also need to know the rotation axis. For example, Uranus rotates completely on its side (i.e. it rotates at 97.77 degrees, while earth rotates at 23 degrees, 26 minutes and 21.4119 seconds). Such things become important for factors like the Arctic ...

8

To my eyes, the belt of Venus looks purple, which didn't makes sense to me, as the very short wavelength of purple light should have been scattered long before arriving back there. Then all made sense when I realized that if you mix blue and red light you get purple. You got that part right. Purple is not violet. Violet is a spectral color at the high ...

7

This optical illusion is due to refraction of visible light due to density gradients near the surface and the fact that the index of refraction in a medium is dependent on the density of the medium. In an atmospheric density gradient light will bend toward the direction of increasing density. When it is cool at the ground and warms up with height this ...

7

Here is not a detailed article, but one you might find some informative thoughts in: http://www.americanscientist.org/issues/pub/sunshine-on-a-cloudy-day On a basic note, any generalization starting with "clouds block x or x%" are far too general to compare actual percentages. It assumes a cloud is a cloud is a cloud. They are not. What a cloud ...

6

First, regarding your assumptions, here is a graphic from this online textbook. As you can see, your first assumption is correct, surface radiation is much more significant than thermals. Your second assumption is also correct, 'Back Radiation' and 'Emitted by Atmosphere' flows are significant, but absorption of heat by the ground from the air isn't even ...

6

Except for Rayleigh scattering (Is the color of the sky the same everywhere on earth?) gases typically do not add any color to atmospheres, they are usually transparent in visible light. The Halogen gases (F$_2$, Cl$_2$,Br$_2$, I$_2$) have color though, and there are a few other colored molecular gases, but you would not expect them in planetary atmospheres. ...

6

Radiation balance only account for energy transfers trough electromagnetic radiation. Something very useful for the Earth as a whole. As it is the only (or most important by far) way of energy exchange between the Earth and the outer space. Energy balance in the other hand, account for energy transfers trough all possible processes, namely radiation, ...

6

Carbonaceous aerosols are formed by a mixture of substances with different chemical, physical, and optical properties. Certain organic substances are mostly transparent to sunlight and therefore do not contribute to Earth warming or cooling. Other substances are mostly reflective, therefore their presence in the atmosphere contributes to Earth's cooling. ...

5

There is no simple relationship since it all depends on the frequency (IR spectral lines for most species of molecules are a mess). The most direct and precise way of calculation is through line-by-line calculation from a large spectrum database. The atmospheric column will be very different based on angle off normal, weather, and even time of day (water ...

5

After my original answer, and some back and forth in the comments, turns out I got the answer right by a bit of fools luck, and we sorted it out... The thing is, despite flux being commonly thought of in physics as BetterExplained.com suggests: Timing: We measure flux at a single point in time. Freeze time and ask “Right now, at this moment, how much ...

4

A body has to emit as much thermal energy as it absobs to remain in thermal equilibrium. The Earth has been doing the same since its formation, i.e, it absorbs solar shorwave radiation by its atmosphere, solid earth and water body, and releases it in the form of longwave radiation. The amount that is released has to be equal to the amount that is absorbed ...

4

It depends on the wavelength. The figure shows the most absorbing species between 6 and 16 µm for a U.S. standard tropical atmosphere (Note: this figure does NOT include the Earth's surface!). Absorption data is taken from Anderson et. al (1986) and simulations are performed with the open-source Atmospheric Radiative Transfer Simulator (ARTS; Eriksson et ...

4

Ozone is indeed a greenhouse gas. But not due to its capacity to absorb/scatter UV radiation, but instead due to its capacity to absorb infrared radiation. In contrast with other greenhouse gases (Like $CO_2$ or Methane), the spectral absorption bands of Ozone are not confined to the infrared part of the spectrum, there are ozone absorption bands also the UV ...

4

It is because longwave (LW) correspond to a negligible part of the solar radiation and shortwave corresponds to a negligible part of solar radiation. You can make an experiment yourself using NASA's Radiance calculator. By adjusting the parameters for Earth's and the Sun you will get the following plot of energy flux at different wavelengths (The red line ...

4

Look at the pysolar docs (http://pysolar.readthedocs.io/en/latest/) under "Estimate of clear sky radiation". The algorithm does not return zeros at night, but instead just plugs those numbers straight in, giving nonsensical values. Filter the results so that if altitude_deg < 0, the radiation is 0. An example just using pysolar, datetime, and pyplot (I ...

4

I think you’re not far off with your understanding, but maybe I can put in a few comments to make things clearer. I often get confused because most diagrams for the Earth energy budget and net radiation balance show more infrared leaving the surface than is ever supplied by solar radiation at the top of the atmosphere in the first place… As you can see, ...

3

I think the short answer to your question is "yes". Getting into the specifics though, it's a lot more complicated. I can't speak to the specific RF and atmospheric interactions, but the changes to weather patterns and long-term climatic anomalies from climate change have been well established by climatologists. From my understanding, the issue with ...

3

What is most mysterious to me, what is the 'factor' of infra-red production by different surface materials. In asking about different surface materials, you are missing the big picture. If you want to understand global warming, simply look at the big picture you provided in the question. The Earth's surface receives more than twice as much energy in the ...

3

Q: What radiates energy back into space? A: anything above absolute zero temperature. That is, absolutely everything, according to the Stephan-Boltzman's law: $$W = \sigma T^4$$ Where $\sigma$ is the Stephan-Boltzman constant and $T$ is the absolute temperature. So of course, volcanoes, steel foundries, forest fires, etc emit a disproportionate amount of ...

3

The way I understand it, the net longwave radiation $L^\star:=L^\downarrow-L^\uparrow$ (maybe with different sign), i.e. the difference between downwelling and upwelling radiation, can be viewed as a vector field (with vanishing horizontal components under the assumption of homogeneous horizontal radiation distribution). This vector field has a divergence $\... 3 When the solar wind is funneled into the Earth's magnetic poles, those particles excite the electrons of molecules in the atmosphere which then bumps those electrons up into another orbital. When the electrons fall back down into their native orbital, they produce a photon of a particular wavelength whose energy is equal to the difference between the energy ... 3 Tropospheric (near the surface) ozone is a powerful greenhouse gas, even in trace amounts. Strataspheric ozone or the ozone layer is opaque to UV rays coming in and it's opaque to IR rays going out so it has both warming and cooling effects. The net effect of a thickening of the ozone layer is a small warming (with some uncertainty), so the ozone layer is ... 2 Beam radiation is direct radiation, e.g. photons that have not been scattered. Diffuse radiation is indirect and has been scattered. Examples of beam radiation from the sky would be from the sun directly to your eye. Diffuse solar radiation would be the blue sky (scattered out of the direct beam by the atmosphere), clouds and anything you can see that is ... 2 It is the warmth of the atmosphere that you feel on your skin. The atmosphere is warmed from the surface of the Earth. Visible light from the sun hits the surface of the Earth and some of it is absorbed, causing the Earth's surface to warm, which is re-radiated as infrared light and is then blanketed by our atmosphere. Without the atmosphere, the ... 2 Assuming your question is about how much of the sun's radiation hits the Earth's surface rather than just reaching the edge of the atmosphere ... The amount of solar radiation that hit's the Earth's surface varies a lot, depending on weather conditions, time of day, day of the year, latitude, altitude, air quality ... It can be anywhere between 0 and ~$...

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