SEA WATER
239
math of a heavy storm or the herald of wind to come.
WaVes are of great importance in helping to keep the surface
-
waters of the sea. mixed, while in_the tidal zone they have
_
left their mark in the many adaptations shown by littoral
animals for protection against the pounding surf.
»_
»
Waves are generally the result of the action of wind
on the sea surface, from the faintest-ripple caused by the
light airs of summer to the tumultuous mountains of water
raised by the full force of a winter’s gale (Plate 83).
The
size of the wave depends upon the Strength of the wind
and upon the distance through which the
can
act.
The— largest waves therefore occur in the; oceas where
there has been sufcient distance over which the wind
'
has blown.
Mr.- Vaughan Cornish in his book on Ocean
Waves states that a fetch of some 600 to 900
miles is
quired to produce the largest waves.
height et a
'
wave is the vertical distance between the summit of the
crest and the‘ deepest part of the;troughl Figures for the
—
height of waves in relation to the speed of the wind are given
-
“
by Cornish as follows
With wind0f 31 miles per hour the
’
height of the wave is 21ft., at 50 m.p.h. it is 35ft., at“ 63.5 —
m.p.h. 4 5 ft., and above”7 5 mzp.h; about: 7ofti; these gures
are under conditions when the wind has had a long feteh.
‘
In a wind of 30 m.p.h. the speed of the Wave
about
25 m.p.h.,…at 50 m.p.h.._it is 40 m.p.h., and at 68 m.p.h.
—
itiS54-'
-
.
"
_',1Ïrhe wave in the open ocean is
of the typeknown as an
0ècillàtory_
That… is,
an _udulaËion , passes ‘ .
through the water, after the…wave has passed, the water '
particlesarèæ still where :they
not received,“
any movement in a horizontal direction.
Actually the
movement of the water particles is a circular one, backward
and upward on the lower half of the wave front, then forward
and upward to the summit of the crest, forward and doWn-
239
math of a heavy storm or the herald of wind to come.
WaVes are of great importance in helping to keep the surface
-
waters of the sea. mixed, while in_the tidal zone they have
_
left their mark in the many adaptations shown by littoral
animals for protection against the pounding surf.
»_
»
Waves are generally the result of the action of wind
on the sea surface, from the faintest-ripple caused by the
light airs of summer to the tumultuous mountains of water
raised by the full force of a winter’s gale (Plate 83).
The
size of the wave depends upon the Strength of the wind
and upon the distance through which the
can
act.
The— largest waves therefore occur in the; oceas where
there has been sufcient distance over which the wind
'
has blown.
Mr.- Vaughan Cornish in his book on Ocean
Waves states that a fetch of some 600 to 900
miles is
quired to produce the largest waves.
height et a
'
wave is the vertical distance between the summit of the
crest and the‘ deepest part of the;troughl Figures for the
—
height of waves in relation to the speed of the wind are given
-
“
by Cornish as follows
With wind0f 31 miles per hour the
’
height of the wave is 21ft., at 50 m.p.h. it is 35ft., at“ 63.5 —
m.p.h. 4 5 ft., and above”7 5 mzp.h; about: 7ofti; these gures
are under conditions when the wind has had a long feteh.
‘
In a wind of 30 m.p.h. the speed of the Wave
about
25 m.p.h.,…at 50 m.p.h.._it is 40 m.p.h., and at 68 m.p.h.
—
itiS54-'
-
.
"
_',1Ïrhe wave in the open ocean is
of the typeknown as an
0ècillàtory_
That… is,
an _udulaËion , passes ‘ .
through the water, after the…wave has passed, the water '
particlesarèæ still where :they
not received,“
any movement in a horizontal direction.
Actually the
movement of the water particles is a circular one, backward
and upward on the lower half of the wave front, then forward
and upward to the summit of the crest, forward and doWn-