Re: Kodak Newsletter (IR part): leaf reflectance

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On 14 Oct 99 at 9:10, Lee Tarpley wrote:

> > > ============================================================
> > > InFocus, the Email Newsletter for Kodak.com Members
> > > Oct. 10, 1999
> >
> > > Infrared: See the World in a Whole New Light
> >
> > Too bad they didn't have it proofread before sending it out....read
> > and shiver:
> >>Green leaves reflect
> > > infrared radiation to keep plants from drying out, and thus
> > > appear icy white in an infrared picture.
> 
> Yes, they really should have proofed it: I am not aware of any scientific
> basis for the claim that leaves reflect VNIR to keep from drying out.

Ah, overlooked that one....good thing they didn't let me proofread 
it....;-))
There might be some kind of argument here, but the way they word it 
(drying vs *icy* white), they might have taken a very simplistic 
approach....ie heat vs cold....and that simply doesn't belong there, 
as near-IR has nothing to do with heat.

Not sure what happens beyond near-IR....but leaves do evaporate 
moisture (some stronger than others, depending on climate), and oddly 
enough there is almost as much near-IR below a tree than in bright 
sunlight....yet it is much cooler below a tree, so far-IR must act 
differently, perhaps in combination with evaporation (=also a 
temperature drop).
Does anyone have a continuous spectral chart on leaves, both 
reflection & transmission? I do have one on the sun spectrum hitting 
the earth, but never seen one for leaves (which probably differ quite 
a bit with different species).





--                 
Bye,

Willem-Jan Markerink


      The desire to understand 
is sometimes far less intelligent than
     the inability to understand


<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]
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