Page 269 - NS-2 Textbook

264 NAUTICAL SCIENCES

Approximate equivalent
sea disturbance scale
'" in open sea
0
" g, Se. Mean height
:. Speed DesC'rlptivc state ofwa\'es
= in knots tenTIS Sea critelion no. Description (in feet)
?
0 Less than 1 Calm Sea like a mirror. 0 Cahn (glassy)
l-:J Light air Ripples with the appearance of scales Calm (rippled) 1;:1
arc formed, but without foam crests.
2 ·1-6 Light breeze Small wavelets, still short but more
pronounced. Crests haye a glassy
appearance and do not break.
3 7-10 Gentle breeze Large \V,wclets. Crests begin to break. 2 Smooth (wRyelets) 2V2
Foam has glass), appearallee. Perhaps
scattered whitecaps.
" 11-16 :\Ioderate breeze Small waves, bec-Qming longer. Fairly :J Slight 5
frequent whitecaps.
5 17-21 Fresh breeze :\fodemte W,lVes, taking a 1110re Moderate 9
pronounced long form. Many whitecaps "
are formed (chance of some sprayJ,
6 22-27 Strong breeze Large w,wes begin to form. The white .5 Rough 14
foam crests are more e).iensiye eH·rywhere
(probably some spray),
7 2·S-33 1Ioderate gale Sea heaps up and white foam from 6 \'ery rough 19
breaking wa\"es begins to he blown in
streaks along the direction of the wind.
(Spray bec"Qllles hea\)').
8 3-4-40 Fresh gale 110derately high \Yaws of greater length. 7 High 2.5
Edges of crests break into spray. The foaIll
is blown in well-marked streaks along the
direction of the wind.
9 41-47 Strong gale High W;l\'es. Dense streaks of foam along 7 31
the direction orthe wind. Sea begins to
roll. Spray may affect viSibility.
to 48_55 Whole gale Very high wa\"es with long, Q\'erhanging 8 Very high 37
crests. The resulting foam in great patches
is blown in dense white streaks along the
direction of the wind, On the whole the
surface of the sea takes on a white
appearance, The rolling of the sea
becomes hea\)' and shoeklike. Visibility is
affected.
11 56-63 Storm Exceptionally high wan's (SmalI- and 9 Phenomenal 45 or
medium-sized ships might for a long time more
be lost to view behind the waves,) The
sea is completely covered with long white
patches of foam l)ing along the direction
of the wind. E\'erywhere the edges of the
\\'a\'e crests are blown into froth,
Visibility affected.
12 Above G.l Hurricane and The air is filled with foam and spray, Sea 9
typhoon completel), white with driving spray.
Visibility yer), seriously affected.
The Beaufort Wind Scale and Correlative Sea Disturbance Scale.

inches. Squalls and typhoons occur over the Bay of Ben- from central Asia now blows southV\Testwru."d across the
gal during this time. continent over the Himalayas and into the southern
Winter (Northeast) Monsoon. As the cold season of the countries. The northeast wind persists from late Septem-
Northern Hemisphere approaches, the continental high ber until April, when the humidity begins to rise for the
over Siberia regenerates and begins to dominate the air next summer monsoon.
circulation over South and Southeast Asia. The wind During the winter monsoon there is little rain, and
now reverses itself and blows from the northeast. The by the time January and February arrive, the soil is
rains of the summer season cease. A warm, IOV\T-pressure parched and cracked, leaves have curled and died, and
area now exists over the Indian Ocean. The cooler, dry air dust lies thick over much of the cmmtryside. Dust in