42
Shore breakers :
As waves enter shallow water, their height (H) increases and their
wavelength (L) decreases . This means,of course,that the steepness of
the wave increases ,and you can readily see this as a wave gets
bigger and steeper just before it collapses as a breaker at the
shoreline.
At least three types of breakers are recognized :
1 – In a spilling breaker, the upper part of the crest becomes
oversteepened and « spills » down the front side of the advancing
wave, continually breaking , and slowly losing its energy across the
surf zone.
2- In a plunging breaker, the entire wave front steepens , curls and
collapses , or « plunges » forward , releasing much of its energy
instantaneously.
3-In a surging breaker, the flat , low waves do not become
oversteepened or actually break , instead they move smoothly up and
then down the face of the beach , refelcting much of their energy
seaward.
(source : invitation to oceanography .2006.p : 236,244)
Exercises :
Exercise : Fill in the blanks with the right words :
1- An ocean wave is usually created by ………………
2- The highest part of the wave is called…………………..
3- The lowest part of the wave is called……………………
4- Waves
are
distinguished
from
one
another
by :………………,…………………….,………….
5- The vertical distance separating the crest from the trough is
……………………
6- The horizontal distance between te crest of one wave and the crest
of the adjacent wave is…………………..
7- The smallest waves which have period of less than one-tenth of a
second are called………………………..