, “. ~ .- ,_ . * -I ' REFERENCE- .? -BBRARY p ;A ~~~ect;~~~vol ...

e _*’ morning sun and by the rising temperature
, I‘ of the ground-below. As thishigh mountain
. u
$r Lirarms’up, it@es;.?ooler air from the val-
-‘, p ____ -I~y-Below.is,dr~tw71-.~rcf.a.Idng t~‘e.sl.~p~;;‘~ ‘I”’ j””
dent@ valleyairflows toward the, base of. ‘*-
;5 fhe, mountair@!dub the slope;kA “mountain-
_.- valley wind” ?stQus created by the tempera- ! ’ .
--‘.. .
‘. ~$re differenc&&nig ht, the.,process reverses ~ ,.
itself; ‘cooled by rapid,r$diation of heat -to.!he:
= ,,dark night sky, high mountain air descend?
“#into the vall~ey,gain$g speed as it becorr 78s --
Y------ I-. %e&ier. Mbuntain-valley winds are generallythought
to be too weak to be a source
‘, ’
, .
*
of, wind energy. In som,e areas, ,however,
. :
~~ ’ ght - r..;;I not be -- the case,
--i
Mountarn breezesdescendrng‘ into a
valley can be warmer or cooler than Jhe
:- ,&ys. Cd01 w$nds flow downhill underlthe
;;influence of gravity, and tend to occur at
night. WarFer winds gain heat energy by. ’
Se&&d winds ‘occur be&use adjacent&nd an&cocean masses have diff&nt *rat&. bf heatin”g and
---..-- fkchnra hrppypc n& lr rl~ dnn ihp nff-shnr~“~~p~&~ night
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lb
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compression,as they d,essend into valleys ’
.;
‘and may bring a local temperature rise of
- 30°F to the vallev. This air is comoressed as
?tdrops into the higher air pressures below.
These winds are known as “Chinooks” or?
. “Santa Anas” in the western United States.
, The higher.temperatures have”been blamed
I ’
for forestfires and a host of malfunctions
associated with over-use of air conditioners. I
The winds of the Chinooks
ribly destructive-speeds.
a
Windspeed kmcteristics
often reach ter-
, -j
, -
Mountain-valley winds. These gentle breezes occur be&use the air over high mountatn slopes warms up,faster
by day a$d cools down mot? rapIdlya\ night.
,’
.,,,,
7%. i, 0
*
given site, there will be a lengthof time , ’
when there is absolutely no wind. For some
-.Winds at virtually all sites have some other length of time, the wind will blow at an :
remarkauy uniform characteristics. At any
average speed, and ,... for another length of
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