Decent into Cleveland

"Bob Gardner" wrote in message .net...
I question the "sun-heated" part of your post. The sun heats the earth,
which in turn heats the atmosphere from the bottom up. Most ice is found in
the top one-third of any cloud.

I don't think this works with a heavy cloud deck and clear on top
where you get little sun penetration. I would think there would have
to be a warmer boundry layer at the tops. This would certainly
account for the much heavier concentration of super cooled moisture.
There was no question the really heavy icing was right at the tops -
you could hear the stuff applying itstelf.


It does take a while for ice to sublimate
off...I have picked up ice climbing through a layer out of Seattle that
didn't disappear for about 30 minutes, and this was in a Baron.

Sumblimate, yes, but I expected the stuff to fall off pretty quickly
once the temp was well above freezing. It didn't - probably took a
long time to warm the plane up.


Glad that it worked out, though.


Me too.

I would suspect your OAT to be incorrect.

Ice invariably will melt off fast, and in big chunks, below the freezing
level.

Karl

Look at any text on the atmosphere and you will learn that temperature
decreases with altitude, cloud cover not withstanding (absent an inversion).
The sun does not heat clouds.

Bob Gardner

"john cop" wrote in message
om...
"Bob Gardner" wrote in message
.net...
I question the "sun-heated" part of your post. The sun heats the earth,
which in turn heats the atmosphere from the bottom up. Most ice is found
in
the top one-third of any cloud.

I don't think this works with a heavy cloud deck and clear on top
where you get little sun penetration. I would think there would have
to be a warmer boundry layer at the tops. This would certainly
account for the much heavier concentration of super cooled moisture.
There was no question the really heavy icing was right at the tops -
you could hear the stuff applying itstelf.


It does take a while for ice to sublimate
off...I have picked up ice climbing through a layer out of Seattle that
didn't disappear for about 30 minutes, and this was in a Baron.

Sumblimate, yes, but I expected the stuff to fall off pretty quickly
once the temp was well above freezing. It didn't - probably took a
long time to warm the plane up.


Glad that it worked out, though.


Me too.

"Bob Gardner" wrote in message news:GwAhb.535167$cF.206989@rwcrnsc53...
Look at any text on the atmosphere and you will learn that temperature
decreases with altitude, cloud cover not withstanding (absent an inversion).
The sun does not heat clouds.

Look, I am no atmospheric expert, but the above is just a plain silly
statement (less charitable types might say stupid). What do you think
happens to all that energy? It ALL get reflected back into space?

Clouds, which you should know even from just from watching the weather
on TV, are insulators of sorts. This means that the sun's energy (the
part that doesn't get reflected) get absorbed by the cloud as it is
transmitted through it. If were an ideal insulating situation, the
temp gradation would be linear, but, obviously, its not (gas laws and
all that), but the principle is the same. My bet is the energy
transfer to the clouds is greatest at the tops and reduces with
altitude according to some unknowable (too many variables) function.
If your statement were correct, the temp at the tops would be the same
during the day as during the night which is, I think, silly. This
does not mean the temp is going to rise as you climb (gas laws again).
What is does mean is that the cloud's capacity to absorb moisture (or
supper cooled stuff) very near the tops could be substantially greater
than near the bottoms.

Read this, and google on cloud temperatures.

http://www.cpc.ncep.noaa.gov/product...uv_clouds.html

When you look at a satellite shot, the whitest clouds are the coldest....at
their tops.

I have attended a whole bunch of international icing conferences hosted by
the FAA, with meteorologists and aerodynamicists from all over the world in
attendance, and I have read the papers they presented at those conferences.
I have written and lectured on airframe icing. Simply stated, you are wrong.

Bob Gardner

"john cop" wrote in message
om...
"Bob Gardner" wrote in message
news:GwAhb.535167$cF.206989@rwcrnsc53...
Look at any text on the atmosphere and you will learn that temperature
decreases with altitude, cloud cover not withstanding (absent an
inversion).
The sun does not heat clouds.

Look, I am no atmospheric expert, but the above is just a plain silly
statement (less charitable types might say stupid). What do you think
happens to all that energy? It ALL get reflected back into space?

Clouds, which you should know even from just from watching the weather
on TV, are insulators of sorts. This means that the sun's energy (the
part that doesn't get reflected) get absorbed by the cloud as it is
transmitted through it. If were an ideal insulating situation, the
temp gradation would be linear, but, obviously, its not (gas laws and
all that), but the principle is the same. My bet is the energy
transfer to the clouds is greatest at the tops and reduces with
altitude according to some unknowable (too many variables) function.
If your statement were correct, the temp at the tops would be the same
during the day as during the night which is, I think, silly. This
does not mean the temp is going to rise as you climb (gas laws again).
What is does mean is that the cloud's capacity to absorb moisture (or
supper cooled stuff) very near the tops could be substantially greater
than near the bottoms.

"Bob Gardner" wrote in message .net...
Read this, and google on cloud temperatures.

http://www.cpc.ncep.noaa.gov/product...uv_clouds.html

When you look at a satellite shot, the whitest clouds are the coldest....at
their tops.

That is not inconsistant with anything I said.

I have attended a whole bunch of international icing conferences hosted by
the FAA, with meteorologists and aerodynamicists from all over the world in
attendance, and I have read the papers they presented at those conferences.
I have written and lectured on airframe icing. Simply stated, you are wrong.

Bob Gardner

Whow, does this mean you get to ignor the laws of physics or do you
get to rewite them?

-The sun does not heat clouds.-

For this to be true, the clouds would have to be perfect transmitter
of all the radiant energy that wasn't reflected. You know thats not
true from the simple fact that it gets darker as you decend into the
cloud. Its a silly statement.

On 10 Oct 2003 16:45:47 -0700, (john cop) wrote:

"Bob Gardner" wrote in message news:GwAhb.535167$cF.206989@rwcrnsc53...
Look at any text on the atmosphere and you will learn that temperature
decreases with altitude, cloud cover not withstanding (absent an inversion).
The sun does not heat clouds.

Look, I am no atmospheric expert, but the above is just a plain silly
statement (less charitable types might say stupid). What do you think
happens to all that energy? It ALL get reflected back into space?


Not all, but in general, clouds reflect much more light and energy
back into space. They insulate the lower levels, but prevent the
sun's heat from reaching the earth.

Cloudy nights tend to be warmer, but cloudy days tend to be cooler.
Transversely, clear nights are colder and clear days tend to be
warmer.

snip

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)

john cop wrote:

Look, I am no atmospheric expert, but the above is just a plain silly
statement (less charitable types might say stupid). What do you think
happens to all that energy? It ALL get reflected back into space?

If you think about the characteristics of glass in the visible spectrum, and
consider that clouds behave similarly in the infrared, you might be a little
more charitable.

Here's another picture to look at:

http://www.nws.noaa.gov/sat_tab.html

Bob Gardner

"john cop" wrote in message
om...
"Bob Gardner" wrote in message
news:GwAhb.535167$cF.206989@rwcrnsc53...
Look at any text on the atmosphere and you will learn that temperature
decreases with altitude, cloud cover not withstanding (absent an
inversion).
The sun does not heat clouds.

Look, I am no atmospheric expert, but the above is just a plain silly
statement (less charitable types might say stupid). What do you think
happens to all that energy? It ALL get reflected back into space?

Clouds, which you should know even from just from watching the weather
on TV, are insulators of sorts. This means that the sun's energy (the
part that doesn't get reflected) get absorbed by the cloud as it is
transmitted through it. If were an ideal insulating situation, the
temp gradation would be linear, but, obviously, its not (gas laws and
all that), but the principle is the same. My bet is the energy
transfer to the clouds is greatest at the tops and reduces with
altitude according to some unknowable (too many variables) function.
If your statement were correct, the temp at the tops would be the same
during the day as during the night which is, I think, silly. This
does not mean the temp is going to rise as you climb (gas laws again).
What is does mean is that the cloud's capacity to absorb moisture (or
supper cooled stuff) very near the tops could be substantially greater
than near the bottoms.

This is an interesting discussion. I wonder if there might be some mixing
of terms that is adding to the confusion. Let's see if we can agree on a
few basics and take it from there.

The dominant part of the sun's emissions that supplies heating to the earth
is in the infrared end of the spectrum. While there are materials that
approach being 100% IR transmissive, water is not one of them. IR is
quickly absorbed in water. This is evidenced by the spectrum of light
present as water thickness is increased. For example, the deeper part of a
swimming pool appears bluer than the shallow part because the sun's light
has transition through more water, 2 x the depth, before reaching our eyes.
The deeper the water, the bluer and darker it looks (provided the water is
clear).

Does a cloud absorb IR radiation? Well, it's made up of water and water
absorbs IR. The answer is yes, clouds absorb IR radiation. If you have any
doubt, think of being outside on a hot day and what happens to the heat you
feel from the sun when a cloud passes overhead. The heat on your skin from
the sun drops significantly if the there is any thickness to the cloud.

This does not refute the thermal satellite imagery in any way. The
satellite imagery shows IR emissions. The earth's surface is much warmer
than the cloud tops and the earth has pretty high IR emissivity. It
registers as warmer due to its higher IR emissions.

Temperature vs altitude within clouds is a different matter and is affected
by several factors, some of which, like convective cooling, may overwhelm
the others.

Just another 2 cents into the discussion.

JimC

"Bob Gardner" wrote in message
news:54Ihb.536556$cF.207547@rwcrnsc53...
Here's another picture to look at:

http://www.nws.noaa.gov/sat_tab.html

Bob Gardner

"john cop" wrote in message
om...
"Bob Gardner" wrote in message
news:GwAhb.535167$cF.206989@rwcrnsc53...
Look at any text on the atmosphere and you will learn that temperature
decreases with altitude, cloud cover not withstanding (absent an
inversion).
The sun does not heat clouds.

Look, I am no atmospheric expert, but the above is just a plain silly
statement (less charitable types might say stupid). What do you think
happens to all that energy? It ALL get reflected back into space?

Clouds, which you should know even from just from watching the weather
on TV, are insulators of sorts. This means that the sun's energy (the
part that doesn't get reflected) get absorbed by the cloud as it is
transmitted through it. If were an ideal insulating situation, the
temp gradation would be linear, but, obviously, its not (gas laws and
all that), but the principle is the same. My bet is the energy
transfer to the clouds is greatest at the tops and reduces with
altitude according to some unknowable (too many variables) function.
If your statement were correct, the temp at the tops would be the same
during the day as during the night which is, I think, silly. This
does not mean the temp is going to rise as you climb (gas laws again).
What is does mean is that the cloud's capacity to absorb moisture (or
supper cooled stuff) very near the tops could be substantially greater
than near the bottoms.