OCEAN SEASONS
247.
‘
months the surface waters become warmed and we have
seen on page 222 that owing to the bad conductivity of the
water this heat is only very slowly dissipated into the
deeper
layers.
The
'
.
result is that a layer
'
is formed at the sur—
.
face with a temperature
two
or
three
.
_
,.
degrees higher than
'
.
that
of
the
water
_
-
*beneath.
,
Between
_
'
-
these
two
water
'
masses thereis a very
.
,
'
narrow layer in which
the temperature
_
WINTER
SPRING
.
N
changes very abruptly
from that of the upper
-
'
'
'
Water mass to that of
_
4
IN
-
the
_—
lower.
This
is
:
'
._
known as the “ dis_
.
'
continuity layer
”
and
'
_
'
,
_
owing
to
certain
’
.
physical properties of
water it becomes ex.
tremely .difcïult for
,
the upper and lower
-
'
_water masses to mix
.onewith another, thus
w
sp
me
SUMMER
'
im—
'_
'
_
_
.
…
‘
penetrable boundary.
and
… under the
m
.
action of very severe ‘
.
.
_
‘
,
'gales can it be broken down.
The depth at.which the
layer is formed becomes deeper as the summer advances,
_
but never gets much below twenty metres.
,
_