How fast does the skin of the airplane cool to surrounding temperatures?

writes:

You really should read the textbooks.

I have.

Try this website:
http://www.islandnet.com/~see/weathe...nts/frost1.htm

I quote from this article from the above site:

The above site is not a textbook.

"Frost forms first on rock, glass, or metal surfaces that lose heat
more rapidly through radiative cooling than the surrounding air. This
is why car windshields frost over before frost forms on surrounding
vegetation. If the surface on which it forms has a temperature below
the frost point, frost may even appear when the officially reported air
temperature is above freezing."

Surfaces such as metal and glass cool more during the night because of
radiative cooling. However, they emit in the infrared, and water
vapor, CO2, and other gases in the atmosphere absorb it, so it doesn't
get very far.

Early in the morning, as temperatures rise, the air may be filled with
moisture but slightly warmer than surfaces that have cooled greatly
during the night and conduct heat well (such as metal). The moisture
in the air may condense (and even freeze) on such surfaces. But there
isn't much radiation loss at ground level unless the air temperature
is lower than surface temperatures. Remember that not only does the
atmosphere absorb infrared, but it also emits it.

The aviation weather textbooks teach the same thing. Another website,
this time by NASA:

http://aircrafticing.grc.nasa.gov/co...4_2_1a_RI.html

This site requires Flash, so I can't read it.

Now try to tell people the dry surface temp won't drop below the
air temp.

I already have.

--
Transpose mxsmanic and gmail to reach me by e-mail.

You'll notice some have claimed to observe frost forming as I had
suggested it might, When theory and observations differ, it's the
theory that should change.



On Dec 8, 7:47 pm, Mxsmanic wrote:
writes:
You really should read the textbooks.I have.

Try this website:
http://www.islandnet.com/~see/weathe...nts/frost1.htm

I quote from this article from the above site:The above site is not a textbook.

"Frost forms first on rock, glass, or metal surfaces that lose heat
more rapidly through radiative cooling than the surrounding air. This
is why car windshields frost over before frost forms on surrounding
vegetation. If the surface on which it forms has a temperature below
the frost point, frost may even appear when the officially reported air
temperature is above freezing."Surfaces such as metal and glass cool more during the night because of
radiative cooling. However, they emit in the infrared, and water
vapor, CO2, and other gases in the atmosphere absorb it, so it doesn't
get very far.

Early in the morning, as temperatures rise, the air may be filled with
moisture but slightly warmer than surfaces that have cooled greatly
during the night and conduct heat well (such as metal). The moisture
in the air may condense (and even freeze) on such surfaces. But there
isn't much radiation loss at ground level unless the air temperature
is lower than surface temperatures. Remember that not only does the
atmosphere absorb infrared, but it also emits it.

The aviation weather textbooks teach the same thing. Another website,
this time by NASA:

http://aircrafticing.grc.nasa.gov/co.../4_2_1a...This site requires Flash, so I can't read it.

Now try to tell people the dry surface temp won't drop below the
air temp.I already have.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Tony wrote:
You'll notice some have claimed to observe frost forming as I had
suggested it might,

Agreed. It's quite common for frost to form on glass and metal
surfaces that are exposed to a clear night sky even when the local air
temperature never drops below 35F at any time.

When theory and observations differ, it's the
theory that should change.

But in this case the observations are in good agreement with the theory
of radiant heat transfer to a clear night sky.

The effect is well known to amateur astronomers since it causes the
optics of their telescopes to cool down below the dew point and have
water condense on them even though the air temperature remains well
above the dew point. Various solutions are used such as slight heating
of the optical elements or installing tubes (dew caps) that extend well
past the end of the telescope and therefore don't allow as much heat
radiation to the cold, clear night sky.

peter writes:

But in this case the observations are in good agreement with the theory
of radiant heat transfer to a clear night sky.

How much frost do you see condensing on Styrofoam?

--
Transpose mxsmanic and gmail to reach me by e-mail.