Dear Bob,
Thanks for
including me.
Cork is right
that on Earth, gravity’s direct effect on escaping radiation
is negligible. The situation is different for the extreme
gravity of black holes.
However,
gravity determines the local air pressure, which is very
nearly the weight, per unit area, of the air above the point
of observation. And gravity is at the heart of convection
of warm, often moist surface air upward and the subsidence
of denser air from higher altitudes that has cooled by
radiation to space. Since convection carries clouds and
water vapor, gravity certainly does have a big indirect
effect on climate.
Cork’s comment:
“It’s absorption, not gravity, that accounts for the
reduction of IR intensity” is similar to those I often make
when I don’t want to confuse an unsophisticated audience. A
clumsy, longer, but more accurate statement would be
“It’s
absorption and emission of thermal radiation, and the
decrease of temperature with altitude over most of the
atmosphere, not gravity, that accounts for the reduction of
IR intensity”
The variation
of temperature with altitude is very important. If the
atmosphere were isothermal, there would be no greenhouse
effect, and if the atmospheric temperature were increasing
with altitude, more greenhouse gases would cool, not warm
the Earth.
Will
There is no mass involved in the photon
blue shift . All I am saying is that the understanding is not
coherent until all the equations are reconciled .
Again , accounting for gravitational energy is not optional .
What quantity is
adiabatic if not total gravitational +
kinetic&radiative ? Further , many papers have shown that
above a certain pressure , pressure dominates the temperature
profile in a very clean curve . And gravity is the prime cause
of the pressure , altho few take their analysis down to that
other macroscopic force . On FaceBook groups like Scientists
Skeptical of Anthropogenic Global Warming the adiabatic answer
is generally accepted .
If somehow spectral filtering can cause asymmetric energy
trapping , what is the asymmetric differential to compute the
effect ?
I'm taking the liberty to add Will Happer to this discussion .
At this point it looks unlikely that I'll get to Las Vegas .
But I expect to be presenting an update on
CoSy on the
upcoming
EuroForth
Zoom .
Bob A
--
On 2021-08-30 11:14, corkhayden@comcast.net wrote:
Hi Bob,
The reduction in IR intensity from the
surface to the top of the atmosphere is 40%, but the
Pound-Rebka gravitational red-shift experiment required the
use of the super-sensitive Mössbauer effect to see ---
something like a couple of parts in 1015 for the
height of a building, or a few parts per billion in the
height of the atmosphere.
There is no comparison. It’s absorption,
not gravity, that accounts for the reduction of IR
intensity.
Yes, I’ll be in Las Vegas.
Cheers,
Cork
It is better to think of radiant energy
density lower in gravity wells rather than its direction .
Even photons blue shift in gravity wells . The equations must
match . If you believe in Newton , and conservation of
energy you
must account for the gravitational energy which
computes as a negative wrt kinetic and radiant . The radiant
has to match the surrounding kinetic temperature .
Equipartition & all that .
The equations should work out to match the difference in
gravitational potential w that ~ 159 w%m^2 . See also my
comments at
http://cosy.com/#PlanetaryPhysics
.
Are you planning to get out to ICCC14 ?
If you are following by blogPosts , you know I have
little time for these issues . I've pressed James Taylor to
have a panel or work session of the unique gathering of
competent physicists . It's vital that these most
foundational issues get hacked out to -- I won't use the
word
consensus but -- agreed quantitative testable
equations .
Good to hear from you . Some time I need to get down &
see Pueblo .
Bob
A
--
Hi Bob,
The surface emits 398 W/m2,
but only 239 W/m2 goes into space. Therefore,
the atmosphere MUST have a net absorption of 159 W/m2.
There is no other option.
Molecular collisions, IR exchanges,
lapse rate, temperature gradients, ocean currents, jet
streams, evaporation, condensation, and all other such
matters are INTERNAL processes that are of considerable
scientific interest, for sure, but irrelevant to the
question. IR does not disappear by lapse rate; IR does
not disappear by gravity; IR does not disappear by
evaporation ….
Energy states are populated according
to exp(-E/kT), and IR plays a role in keeping that
equilibrium. But 159 W/m2 has to be absorbed
(in net; more than that is absorbed, as some is also
emitted).
That 159 W/m2 difference is
simply re-circulated heat. It leaves the surface by
radiation, and is returned.
Cheers,
Cork
You cannot
leave gravitational energy out of the equation .
The adiabatic total energy balance between
gravitational ` potential and kinetic energy is
what gives us the temperature `
lapse gradient .
Nothing to do with any equationless spectral filter heat `
trapping .
Tyndall just showed that gases like any opaque or other
apparently transparent substances like glass absorbed some
wavelengths and came to a temperature equilibrium based on
, well , the computation at
http://cosy.com/Science/ComputationalEarthPhysics.html#EqTempEq
.
--
On 2021-08-29 19:07, Science and
Environmental Policy Project wrote:
The difference
between the thermal radiation at the surface and
outgoing radiation at the top of the atmosphere is 159
W/m2, which keeps the average temperature of the earth
about 34°C warmer than it would be without greenhouse
gases. This is particularly important because as
explained by John Tyndall following his experiments
starting in 1859, greenhouse gases prevent the land
masses from going into a deep freeze each night,
killing all growing plants.
--
