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How does sun heat the air?



 
 
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  #31  
Old December 19th 17, 06:26 AM posted to rec.aviation.soaring
2G
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Posts: 1,439
Default How does sun heat the air?

On Tuesday, November 14, 2017 at 9:01:17 AM UTC-8, Dan Marotta wrote:
I kinda lost faith in wikipedia after a former global warming evangelist
turned "climate change denier" found his wiki entries deleted almost as
quickly as he would post them.Â* Are they, too, bearers of the banner?

On 11/13/2017 9:07 PM, Steve Koerner wrote:
Don't forget to include water vapor in your hypothesising:

https://en.wikipedia.org/wiki/Electr...ption_by_water



On Sunday, November 12, 2017 at 10:44:48 AM UTC-7, wrote:
Is is a great question, and one I am currently working with. Our understanding of the atmosphere, I think, is incomplete, and needs reviewed and updating. Doing so will easily explain such a problem. As it stands there are deep contradictions and paradoxes associated with radiation and the atmosphere.
Air is a near perfect insulator (it has a conduction value of near zero; 0.024 no units) so the thought heat energy is transferred this way cannot be so .
Add to that: air is assumed to (with the exception of about 1% greenhouse gases) not absorb or emit any IR radiation: this is a contradiction to Radiation theory, and quantum mechanics where all matter above absolute 0 Kelvin radiates IR.

So something is wrong, because the air does increase, and decrease in temperature, and does so quickly.
My hypothesis is O2 and N2 (99% of the dry atmosphere) do absorb and emit IR radiation: I have the quantum theory to show where they do, the experimental instrument to show it does, and the application proof to show it does.

I am currently writing up my work - it is a massive undertaking; I predict the biggest upset is science of our time: greenhouse theory will collapse. Special greenhouse atmosphere theory is pre quantum mechanics 19th Century science; it has not been updated with 20th Century knowledge - yet.


--
Dan, 5J


Right, a democratic organization isn't always democratic when zealots take it upon themselves to be societies censors because they know what truth is.

Tom
  #32  
Old December 19th 17, 09:34 AM posted to rec.aviation.soaring
Tango Whisky
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Default How does sun heat the air?

Le mardi 19 décembre 2017 05:20:26 UTC+1, a écritÂ*:
Sigh ... there's a great deal of misinformation here. A correct answer is long and complicated, but the short of it is that there are numerous gas absorption bands in the "solar shortwave" -- these range from the Hartley-Huggins bands of Ozone in the UV (responsible for the stratosphere), the Chappuis band of O3 in the mid visible, a variety of weak absorption bands of Oxygen, and then a substantial H2O absorption band at 940 nm ... with increasing numbers of absorption bands in the near infrared due to a variety of trace gases starting with H2O and CO2.

So sunlight can and does heat the atmosphere through direct absorption; absorbing aerosols also play a role.

Nonetheless, as is everybody's direct experience -- a lot of light gets down to the ground on a cloud-free day.


Well of course you have a variety of absorption bands, but if you take absorption coefficients and spectral intensity into account, it all boils down to one thing: Albedo rules.
  #33  
Old December 19th 17, 10:58 AM posted to rec.aviation.soaring
Paul Ruskin[_2_]
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Default How does sun heat the air?

On Tuesday, December 19, 2017 at 4:20:26 AM UTC, wrote:
Sigh ... there's a great deal of misinformation here. A correct answer is long and complicated, ...


Any chance of putting some numbers on it? At least approximately?

Where does the energy end up, and by which mechanism?

Paul

  #34  
Old December 19th 17, 08:50 PM posted to rec.aviation.soaring
[email protected]
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Default How does sun heat the air?

Agreed on the Albedo rules observation. I experienced low albedo recently but found that zinc, exercise, and weight loss brought it right back up. Changed my life.
  #35  
Old December 19th 17, 10:00 PM posted to rec.aviation.soaring
Dan Daly[_2_]
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Posts: 718
Default How does sun heat the air?

On Tuesday, December 19, 2017 at 2:50:44 PM UTC-5, wrote:
Agreed on the Albedo rules observation. I experienced low albedo recently but found that zinc, exercise, and weight loss brought it right back up. Changed my life.


I would have thought that Fettuccine Albedo would make you gain weight...
  #36  
Old December 19th 17, 10:11 PM posted to rec.aviation.soaring
Darryl Ramm
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Posts: 2,403
Default How does sun heat the air?

I want to know if the sun can warm the latte in my cup holder. I'm also considering dual cup holders for redundancy.
  #37  
Old December 20th 17, 02:03 AM posted to rec.aviation.soaring
Eric Greenwell[_4_]
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Posts: 1,939
Default How does sun heat the air?

Tango Whisky wrote on 12/19/2017 12:34 AM:
Le mardi 19 décembre 2017 05:20:26 UTC+1, a écrit :
Sigh ... there's a great deal of misinformation here. A correct answer is long and complicated, but the short of it is that there are numerous gas absorption bands in the "solar shortwave" -- these range from the Hartley-Huggins bands of Ozone in the UV (responsible for the stratosphere), the Chappuis band of O3 in the mid visible, a variety of weak absorption bands of Oxygen, and then a substantial H2O absorption band at 940 nm ... with increasing numbers of absorption bands in the near infrared due to a variety of trace gases starting with H2O and CO2.

So sunlight can and does heat the atmosphere through direct absorption; absorbing aerosols also play a role.

Nonetheless, as is everybody's direct experience -- a lot of light gets down to the ground on a cloud-free day.


Well of course you have a variety of absorption bands, but if you take absorption coefficients and spectral intensity into account, it all boils down to one thing: Albedo rules.


The air that makes our thermals is the air heated near the surface. Look at a RAOB
on a soaring day, and you can see the thin super-adiabatic layer near the surface,
then the much thicker adiabatic lay above to the inversion level. We all know some
surface areas get hotter than others and produce thermals, while any direct
heating of the atmosphere is uniform, and unlikely to produce thermals.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

  #38  
Old December 20th 17, 03:28 AM posted to rec.aviation.soaring
[email protected]
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Posts: 36
Default How does sun heat the air?

The people who really care about this stuff are climatologists (and climate modelers), and increasingly the solar power community. The issue as far as the soaring community is concerned is that most of the sunlight that is lost to absorption in the atmosphere is mostly-always lost

* UV is absorbed in the stratosphere; as far as total energy is concerned there is not much variability in what gets to the ground.

* Chappuis-band O3 absorption (in the visible red) can change the surface heat flux a few percent, no more

* the big H2O band at 940 nm is very important climatologically .. but is perhaps 5% of total energy flux and not as variable as people might think

* H2O and CO2 (and some others) at wavelengths 1.4 microns lead to substantial extinctions in the 1.4 - 3 micron wavelength domains -- but our human eyes don't see that, the sun's solar output is decreasing at longer wavelengths, nor do silicon solar cells get energy from these wavelengths.

When you look at energy balance commonly more than 20% of the sun's radiation is absorbed in the atmosphere, and this is very important to the thermal structure of the atmosphere, but it isn't highly variable (as a fraction of total energy) so people just don't pay too much attention to it, for purposes like soaring.

This energy ends up as heat, distributed non-uniformly through the atmospheric column. The most blatantly obvious effect is that we have a stratosphere; there are also climatically-important consequences to this in the troposphere. Most of this heat is deposited at altitudes where we don't fly.

The dominant issues that effect lower-boundary layer heating rates are pretty obvious: clouds! Yes, surface-albedo ... and then a very large factor not discussed here is what meteorologists call the "Bowen ratio:" the ratio of the latent-to-sensible heat flux from the surface ... how much of the heat is used to evaporate water.

Deserts are good for soaring because most of the captured radiation does go to sensible heat.

A "secret" most western pilots don't know -- the best soaring season in the northeast is spring, before the trees leaf out. It's our desert. After they leaf out ... then every damned tree is a water-sucking nuisance ... and a subtle point is that deciduous trees flux more water than conifers ... there are easily-observable differences in Bowen-ratio from deciduous vs conifer forests.

More subtly there is a second "good" period in the fall when the trees lose their leaves, although with the declining sunlight it's not really great. But since the time of Benjamin Franklin naturalists noted that stream flows in the northeast jump after the trees lose their leaves in the fall, and correctly attributed the reason for this.

One of several reasons "the high ground" is usually better soaring (everywhere) is that water runs off it; the trees are almost always water-stress limited and shifted to species (conifers) that do that better. A water-stressed tree keeps its stomata closed: doesn't flux water but also cannot photosynthesize.

Plants do change the surface albedo, usually lower it. Plants look green because they don't use green light, and they want to reflect it to avoid its heat. They also increase the albedo at longer wavelengths. But this effect on albedo is usually less important that their water flux ... if they aren't water stressed.

Soil moisture can be measured (sort-of) by remote sensing in the microwave, and there are very large variations in soil moisture temporally (ask any farmer), but also spatially across the terrain ... in places (not our western deserts) where there's enough water for plants to grow generously.

Hey Eric Greenwell? You still flying around Richland Washington? I flew with you, and towed you years ago when I worked at PNL. It's pretty arid out there ... but nobody finds good thermals coming up off the big irrigated crop circles. In desert terrains stay away from green like the plague.

In the northeast the hierarchy is plowed-fields better than conifers, conifers better than growing hay or corn UNLESS the farmers are complaining about a dry spell, say out of the river bottoms and anywhere with deciduous trees, worse yet willows.






  #40  
Old December 20th 17, 04:20 AM posted to rec.aviation.soaring
Michael Opitz
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Posts: 318
Default How does sun heat the air?

At 02:28 20 December 2017, wrote:
The people who really care about this stuff are climatologists (and
climate=
modelers), and increasingly the solar power community. The

issue as far
a=
s the soaring community is concerned is that most of the sunlight

that is
l=
ost to absorption in the atmosphere is mostly-always lost=20

* UV is absorbed in the stratosphere; as far as total energy is

concerned
=
there is not much variability in what gets to the ground. =20

* Chappuis-band O3 absorption (in the visible red) can change the

surface
=
heat flux a few percent, no more

* the big H2O band at 940 nm is very important climatologically ..

but is
p=
erhaps 5% of total energy flux and not as variable as people might

think=20

* H2O and CO2 (and some others) at wavelengths 1.4 microns

lead to
substa=
ntial extinctions in the 1.4 - 3 micron wavelength domains -- but

our
huma=
n eyes don't see that, the sun's solar output is decreasing at longer
wavel=
engths, nor do silicon solar cells get energy from these

wavelengths. =20

When you look at energy balance commonly more than 20% of the

sun's
radiati=
on is absorbed in the atmosphere, and this is very important to the
thermal=
structure of the atmosphere, but it isn't highly variable (as a

fraction
o=
f total energy) so people just don't pay too much attention to it,

for
purp=
oses like soaring.

This energy ends up as heat, distributed non-uniformly through the
atmosphe=
ric column. The most blatantly obvious effect is that we have a
stratosphe=
re; there are also climatically-important consequences to this in

the
trop=
osphere. Most of this heat is deposited at altitudes where we

don't fly.
=
=20

The dominant issues that effect lower-boundary layer heating rates

are
pret=
ty obvious: clouds! Yes, surface-albedo ... and then a very large

factor
n=
ot discussed here is what meteorologists call the "Bowen ratio:"

the ratio
=
of the latent-to-sensible heat flux from the surface ... how much of

the
he=
at is used to evaporate water.

Deserts are good for soaring because most of the captured

radiation does
go=
to sensible heat. =20

A "secret" most western pilots don't know -- the best soaring

season in
th=
e northeast is spring, before the trees leaf out. It's our desert.

After
=
they leaf out ... then every damned tree is a water-sucking

nuisance ...
an=
d a subtle point is that deciduous trees flux more water than

conifers ...
=
there are easily-observable differences in Bowen-ratio from

deciduous vs
co=
nifer forests. =20

More subtly there is a second "good" period in the fall when the

trees
lose=
their leaves, although with the declining sunlight it's not really

great.
=
But since the time of Benjamin Franklin naturalists noted that

stream
flow=
s in the northeast jump after the trees lose their leaves in the fall,

and
=
correctly attributed the reason for this.

One of several reasons "the high ground" is usually better soaring
(everywh=
ere) is that water runs off it; the trees are almost always water-

stress
li=
mited and shifted to species (conifers) that do that better. A
water-stres=
sed tree keeps its stomata closed: doesn't flux water but also

cannot
photo=
synthesize.=20

Plants do change the surface albedo, usually lower it. Plants look

green
b=
ecause they don't use green light, and they want to reflect it to

avoid
its=
heat. They also increase the albedo at longer wavelengths. But

this
eff=
ect on albedo is usually less important that their water flux ... if

they
a=
ren't water stressed.

Soil moisture can be measured (sort-of) by remote sensing in the
microwave,=
and there are very large variations in soil moisture temporally

(ask any
f=
armer), but also spatially across the terrain ... in places (not our
wester=
n deserts) where there's enough water for plants to grow

generously. =20

Hey Eric Greenwell? You still flying around Richland Washington? I

flew
w=
ith you, and towed you years ago when I worked at PNL. It's

pretty arid
ou=
t there ... but nobody finds good thermals coming up off the big

irrigated
=
crop circles. In desert terrains stay away from green like the

plague.

In the northeast the hierarchy is plowed-fields better than conifers,
conif=
ers better than growing hay or corn UNLESS the farmers are

complaining
abou=
t a dry spell, say out of the river bottoms and anywhere with

deciduous
tre=
es, worse yet willows. =20


Thanks for a great post!

RO


 




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