Atmospheric temperature - heat balance and albedo

The main source of heat and light on Earth is, of course, the Sun. However, what comes to us is only the part filtered through individual layers of the atmosphere.

Solar radiation

The sun sends various types of energy into space:

• electromagnetic radiation
  • visible - light visible by the human eye
  • long-term - warmth
  • infrared
  • ultraviolet
  • short
  • microwave
  • X-rays
• corpuscular radiation

Added to this is the fact that radiation can, for example, be reflected or absorbed by clouds. [rs-ads block="W środku"]

Radiation balance

When considering the radiation balance, we take into account short- and long-term. Assuming that + 100% short wave radiation passes through the upper atmosphere boundary, it travels as follows:

• -17% is absorbed by the atmosphere
• 18% is dispersed in the atmosphere, incl
  • 11% reaches the surface
  • -7% is reflected back from the air particles
• -24% is reflected from the top of the clouds
• -4% bounces off the ground
• 37% reach Earth

that is, we sum up: 100-17-7-24-4 = +48 reaches the surface of the planet and we check: 11 + 37 = +48, which is correct :) Now let's take a look at long-wave radiation:

• land balance:
  • -114% of heat is given off by the ground
  • -30% given off by steam and airflows
  • + 96% is atmosphere back radiation
• atmosphere balance
  • + 30% given by steam and air
  • + 109% heat from the ground
  • -96% return radiation
• balance above the atmosphere
  • -5% ground heat that passes through the atmosphere
  • -60% heat radiated by the atmosphere

And we count if he agrees: soil: -114-30 + 96 = -48 => it is the 48 that the short-wave radiation "wet" the soil atmosphere: + 30 + 109-96 = 43 => here 5% is missing from the bill, which passes through the atmosphere and escapes into space above the atmosphere: -5-60 = -65 general radiation escape: -35-65 = -100

Conclusions

• what the sun gives us is in 1/3 reflected from the clouds, atmosphere etc.
• almost half of the radiation is absorbed/absorbed by the planet's surface
• some heat escapes into space
• in practice, the balance sheet is disturbed by, among others the greenhouse effect

Of course, it should also be remembered that the solar radiation intensity and surface it affects depends on the angle of incidence, which depends on:

• seasons and distances from the equator. Hence, it is hot at the equator (angle of incidence 90 degrees), and not necessarily at the poles. This effect is mitigated by changing the tilt of the Earth relative to the Sun with subsequent seasons.
• reliefs - this is best seen in the mountains, where there are slopes with high exposures, but also those that are in the shade zone and there the sun never reaches
• time of day - probably no one doubts that it is the warmest at noon. And all this because at noon the radiation has a shorter path through the atmosphere than at sunrise or sunset. Therefore, less heat has a chance to escape.

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Albedo

An important concept that cannot be forgotten is albedo , i.e. the ratio of radiation that is reflected and that which reaches a given surface. This ratio is affected by both the colour of the substrate and its type. Albedo is expressed as a percentage. And so for example:

• snow - 75-95%
• sea ice - 36-50%
• sand dunes - 20-45%
• savanna - 25-30%
• green grass - 26%
• city - 15-25%
• agricultural field - 15-25%
• deciduous forest - 10-20%
• coniferous forest - 5-15%
• asphalt - 5-10%

As you can see, the larger the albedo, the greater the reflection and less absorption. Can we use it in practice? Of course :) If you want to build a field shower and have hot water in it without special heating, you should paint the tank with water, preferably metal (thermal conductivity), black and exposed to the sun. In the evening the water should be warm :) And one more remark about the heat balance and albedo, which is obvious, but you have to write about it. The water heats up very slowly, much slower than land, but on the other hand, it slowly releases heat and can store it for a long time. These differences are most easily observed on the example of the sea breeze, but they also have an impact on the climate.