Mark,
Here is a reference based on empirical data for north-south-facing
slope differences:
Tajchman, S.J., M.M. Harris, and E.C. Townsend. 1988. Variability of
the radiative index of dryness in an Appalachian watershed. Agric.
For. Meteorol. 42:199-207. The study aimed to explain why
north-facing slopes are more mesic than south-facing slopes, but I
assume they measured exposure differences. Not sure if they compared
radiative indices of dryness of east- and west-facing slopes.
Robert Leo Smith cites this study and gives a description of the
effect in his fifth edition textbook, Ecology and Field Biology -
Chapter 4-Climate:Microclimate/North Facing and South Facing Slopes.
Doesn't say anything about east-west-facing slope differences.
Hope this helps.
Steve Brewer
At 5:35 PM +0100 8/13/10, Mark Wilson wrote:
Hi folks,
I am looking for a reference which states
(1) that in the northern hemisphere the north side of boulders are
less exposed to the sun than the south side
and
(2) that the east side of boulders are exposed to the sun only in the
morning when temperatures tend to be cooler while west sides are
exposed during the afternoon when temperatures tend to be higher and
as a result the north and east side of boulders are likely to stay
cooler and damper longer.
Any suggestions?
Mark
--
J. Stephen Brewer
Professor
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PO Box 1848
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University, Mississippi 38677-1848
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