... "Figure 1 (below) shows the month-by-month surface shortwave (solar, “SW”) and longwave (thermal infrared, “LW”) radiant energy flows at the SURFRAD station in Goodwin Creek, Mississippi.
The US maintains something called the SURFRAD (Surface Radiation Budget) Network of eight surface measuring stations.
These have a variety of sensors that, as the name suggests, measure a variety of surface radiation flows.
These are calibrated annually to assure accurate measurements.
They collect data on an almost continuous basis, 24/7/365.
The stations have data from 1995 to the present.
So I picked a SURFRAD station at random, Goodwin Creek, Mississippi.
And I picked a year at random, 2014, and downloaded the monthly average data from here.
... I thought “I wonder how well this agrees with the CERES satellite-based dataset?”
So I added the corresponding CERES data to the chart.
Here is the result.
Figure 1. SURFRAD and CERES data, Goodwin Creek, Mississippi. The CERES data is for the 1° latitude by 1° longitude gridcell where the SURFRAD station is located. The background shows the Goodwin Creek SURFRAD station:
... folks have been questioning lately whether the CERES data is accurate enough for the type of analyses that I do, whether it is fit for the purpose
… this should allay some of their concerns.
... The red / orange lines show the amount of solar energy that is absorbed by the surface.
It’s the net of the downwelling solar minus the solar that is reflected back upwards from the ground.
As you can see, the annual average solar energy absorbed by the surface is about 150 watts per square meter (W/m2).
The yellow|gold lines, on the other hand, show the upwelling longwave (thermal infrared) energy,
energy that is radiated upwards from the surface.
The annual average upwelling long wave energy is about 395 W/m2.
... for all of you that think that downwelling radiation from the atmosphere is a mirage, here’s the question.
If on an ongoing basis the surface is only absorbing 150 W/m2 of solar energy and is radiating 395 W/m2 of energy … why isn’t it frozen solid?
... If it is constantly radiating far more energy than it is absorbing … why isn’t it a block of ice?
To me, the obvious answer is, the surface is also absorbing downwelling radiation from the atmosphere.
In Figure 1 above, the blue / cyan lines show the total of the net solar (SW, red /orange lines), plus the downwelling long wave thermal infrared (LW) from the atmosphere.
The annual average of the net downwelling radiation at the surface (SW +LW), the total energy absorbed by the surface, is about 490 W/m2.
This is about a hundred W/m2 more than the energy that is lost to radiation,
with the rest of the surface energy loss being in the form of the net of the sensible and latent heat lost gained and lost by the atmosphere via convection and conduction.
... If you don’t think that downwelling LW radiation leaves the earth warmer than it would be if there was no atmosphere, you need to explain the mystery source of the additional energy necessary to keep the earth from freezing.
And no, it’s not geothermal heat.
We know from borehole measurements that geothermal heat, in general, is on the order of a tenth of a W/m2 or so … and we’re missing about 395 W/m2 emitted minus 150 W/m2 absorbed equals 245 W/m2 necessary to prevent freezing.
So what is the mystery source?
Let me add that the most excellent agreement between the SURFRAD and the CERES data means that it’s not instrumental error, or scientists who don’t know what they are measuring.
So where is the energy coming from?
SOME INTERESTING COMMENTS:
"Certainly, the “politics or religion” is a motivating force for those who deny the radiative “greenhouse” effect.
I think another factor is that most of us don’t notice the radiation around us from objects at “ordinary” temperatures.
We only really notice radiation from hot stoves, or from direct sunlight, when we can’t ignore it.
It’s hard to grasp that all solid objects are both radiating and absorbing radiation all the time;
it’s even harder to grasp that the air we breathe is absorbing radiation and radiating back at us.
So, when told that the atmosphere is radiating heat back to the surface, some folks will refuse to accept it because it is something outside their everyday experience.
Even if we know the physics, most of us still go through our daily lives without noticing or thinking about the radiation we are exchanging with our environment.
If we can’t feel it, it takes an intellectual effort to accept it as reality."
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"Many scientific arguments over the centuries have been resolved by the realization that we have been asking the wrong question.
The question is not whether downwelling radiation exist.
Of course it does, because our atmosphere is not perfectly transparent.
But is this downwelling radiation the cause or the result of warming?
That is the question we have failed to ask.
As a result, downwelling radiation has become a red herring.
The true cause of warming is a change in the effective radiation height coupled with the lapse rate.
This is well established science.
As you increase the effective radiation height to a cooler portion of the atmosphere, this reduces outgoing radiation.
And since incoming and outgoing radiation must be equal over time,
the earth must warm to increase outgoing radiation to restore the radiative balance.
As such downwelling radiation is the effect, not the cause.
This misconception is likely why folks intuitively reject the idea that downwelling radiation causes warming.
Because it doesn’t.
Downwelling radiation is the result, which explains why there is a poor correlation between temperature and CO2 over the past 500 million years.
What causes the warming is an increase in the effective radiation height coupled with the lapse rate,
which reduces outgoing radiation,
which forces the earth to warm to restore the long term radiative balance."