Infrared Sensitivity to Dissolved Water

["J. Henderson" <hendersonj@xxxxxxxxxxxxxxx>]

Dear Mr. Costa:

I noted your request from the infrared list:

________________________________________________________

>I red in this book:

>Earth's Nature From Space by N.P. Kozlov

>that, brightness of materials depend on their water content. From the 
>graph that is presented it looks that this is specially true for infrared 
>radiation. The same material (for example, soil) with different water 
>contents will have different brightness.

>Does anyone know more texts about this ?

________________________________________________________

There are a number of studies in the literature which indicate that
infrared film can detect varying amounts of water present as a function of
density (brightness) recorded on the film.  Many crop and soil marks and
other land scars have not yet disappeared to the infrared spectrum, even
though they are indiscernible to the eye or fail to record on panchromatic
film.  Strandberg used aerial infrared recording to record traces of
disturbed soil.  Hydrologists also use infrared to map the presence of
clear or turbid water on the landscape.  I refer you to the following for a
discussion of those applications:

1.  Strandberg, C.H. 1964. An aerial water quality reconnaissance system. 
Photogram. Eng., 30, 46-54.

2.  Strandberg, C.H. 1966. Water quality analysis.  Photogram. Eng., 32,
234-248.

3.  Strandberg, C.H. 1967a. Aerial discovery manual. New York:  John Wiley
and Sons, Inc.

4.  Strandberg, C.H. 1967b. Photoarchaeology.  Photogram. Eng., 33,
1152-57.

5.  Matthews, S.K. 1968.  Photography in Archaeology and art.  London: 
John Baker, Publishers.

However, I am unaware of any application in which infrared film has been
used as a quantitative measure of water present in soil.  I suspect that
such a measurement is possible if a standard reflective object (a gray
card, for example) were placed in the scene to calibrate relative exposure.

Hope this helps you.

Sincerely,

James W.  Henderson
Applied Photographic Research
804 Center Street, Oregon City, OR 97045-1951
(503) 655-6817

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