"Effect of Clouds on Global Upwelling Radiation"

Source:

https://phzoe.com/2021/02/12/effect-of-clouds-on-global-upwelling-radiation/?blogsub=confirming#subscribe-blog

"I downloaded and analyzed 10 Gigabytes of data fully covering years 2003 to 2019 from “the only project worldwide whose prime objective is to produce global climate data records of ERB [Earth’s Radiation Budget] from instruments designed to observe the ERB”in order to see the effect of clouds at the surface, especially the Upwelling Longwave Radiation.

NASA reminds us … 

High clouds are much colder than low clouds and the surface.

They radiate less energy to space than low clouds do.

The high clouds in this image are radiating significantly less thermal energy than anything else in the image.

Because high clouds absorb energy so efficiently, they have the potential to raise global temperatures.

In a world with high clouds, much of the energy that would otherwise escape to space is captured in the atmosphere.

High clouds make the world a warmer place.

If more high clouds were to form, more heat energy radiating from the surface and lower atmosphere toward space would be trapped in the atmosphere, and Earth’s average surface temperature would climb.
    — NASA

 In contrast to the warming effect of the higher clouds, low stratocumulus clouds act to cool the Earth system.

Because lower clouds are much thicker than high cirrus clouds, they are not as transparent: they do not let as much solar energy reach the Earth’s surface.

Instead, they reflect much of the solar energy back to space (their cloud albedo forcing is large).

Although stratocumulus clouds also emit longwave radiation out to space and toward the Earth’s surface, they are near the surface and at almost the same temperature as the surface.

Thus, they radiate at nearly the same intensity as the surface and do not greatly affect the infrared radiation emitted to space (their cloud greenhouse forcing on a planetary scale is small).

On the other hand, the longwave radiation emitted downward from the base of a stratocumulus cloud does tend to warm the surface and the thin layer of air in between, but the preponderant cloud albedo forcing shields the surface from enough solar radiation that the net effect of these clouds is to cool the surface.
    — NASA

The project keeps track of 4 different types of observed LW_UP:
All is normal observed sky.

Clr (clear) is no clouds.

AllNoAero is All minus aerosols.

Pristine is Clr minus aerosols.

Since clouds play an important role in Earth’s supposed greenhouse effect, and this effect leads to a supposed serious warming at the surface, we should see a very large difference between all these 4 scenarios.

But in fact there is very little difference.

The difference in surface LW_UP between a Pristine sky (no clouds, no aerosols) and All sky (see above cloud data) is just 0.82 W/m².

I would even argue it might be ZERO.

It’s only not zero because a satellite can’t measure the same scenario in the same place at the same time.

They can only measure some place nearby or same place at another time.

Even if I’m wrong on this, this value is still very unimpressive.

Now let’s look at downwelling longwave radiation (LW_DN) and longwave radiation at the top of the atmosphere (TOA_LW):

... The standard greenhouse effect narrative is that infrared absorbing gases prevent radiation from reaching space and this causes warming at the surface (thus more radiation).

Well we clearly see that’s not case.

If clouds (water vapor + aerosols) hardly changes outgoing surface radiation, then the whole hypothesis is in error.

Less top-of-atmosphere outgoing radiation doesn’t cause surface heating and thus more radiation from the surface, despite the increase in downwelling radiation."