Sea surface state (MS) is determined visually and depends upon wind force. Wind force is
visually described both in words and in Beaufort wind scale numbers (Forces).
We have made an attempt to review manuals and guides on ship wind observations and so
far managed to find the only one, namely, “Instructions to hydrometeorological stations
and posts”(Issue 9, Part 2, 1948), which gives the joint table of wind force and sea surface
state described by the so-called Beaufort-Simpson scale (Table 1). This table was used in
Russian observations to estimate both wind force and the MS parameter.
In the period of 1962-1992 the same Beaufort scale was used and word description of
indicators required to define the surface state of an ocean, sea, lake or large water body
(MS) corresponds to that given in Table 3, which we included into the format.
Since 1992 the Beaufort scale has been modified. Wind speed increased and the
corresponding wind force given in numbers remained unchanged (Table2).
In original historical tables the MS parameter has already been encoded and given in
Russian national manuals on ship observations do not mention that Beaufort scale should
be used to estimate MS. They give only Table 3, which we include into the format.
In my opinion, when MS is converted to wind force Beaufort scale used at the time, when
observations were made, should be applied.
The digitization work is go on OK. At present time we prepare 100 cruises-files with
meteorological and actinometric observations and forwarding to NCAR in a week.
Wind force, wind speed and sea surface state
Wind force Sea surface state with wind waving
Visual wind force
Wind speed m/s
Word description Indicators for
on board a ship
description wind force and
0 Calm 0,0-0,5 Flags are still Calm glassy 0 Like a mirror
1 Light airs 0,6-1,7 Calm rippled 1
2 1,8-3,3 Smooth wavelets 1-2 Small wavelets,
Light breeze Flags slightly no breaking, no
waver in the wind foam
3 Gentle 3,4-5,2 Flags flap in the Slight 2 Large well-
breeze wind defined wavelets,
flocks of sheep
here and there
4 Moderate 5,3-7,4 Small flags and a Slight to Moderate 3 Small waves,
breeze pendant in streaks breaking, flocks of
(stretch) sheep everywhere
5 Fresh breeze 7,5-9,8 Big flags in Moderate 4 Moderate waves,
streaks blocks of sheep
6 Strong 9,9- Wind begins to Rough 5 Large waves,
breeze 12,4 sing in the wires foam and spray
7 Near gale 12,5- Very rough 6 Sea heads up,
15,2 foam in streaks
8 ветер Gale 15,3- Very rough 7
18,2 It is difficult to High waves, dense
9 18,3- walk a deck 7 foam, spray
Strong gale 21,5 against the wind High impairs visibility
10 21,6- 8 Very high
Storm 25,1 Very high tumbling waves,
surface white with
11 Violent 25,2- 9
storm 29,0 Phenomenal Exceptionally high
12 Более 9 waves, sea
29,0 covered in foam,
Harricane air filled with
spray and foam,
Beaufort scale to estimate wind force
Wind speed Wind impact on Sea state
Wind Word M/s Km/h knots ship and rigging
0 0-0,2 0-1 0-1 Air is Calm glassy
Calm (0) (0) (0) absolutely calm.
Pendant is still
1 Light airs 0,3-1,5 1-5 1-3 Light air is felt
(1) (3) (2) from time to Calm rippled
2 1,6-3,3 6-11 4-6 Continuous
Light breeze (3) (8) (5) breeze. Flags Small wavelets
in the wind
3 Gentle 3,4-5,4 12-19 7-10 Flags and Large wavelets, some
breeze (5) (15) (8) pendants flap in breaking, glassy foam
4 5,5-7,9 20-28 11-16 Small waves, breaking,
Moderate (7) (24) (13) Pendant is in a flocks of sheep here
breeze streak and there
5 8,0-10,7 29-38 17-21 Big flags flap in
Fresh breeze (9) (33) (19) the wind and Moderate well-defined
are instreaks. waves, flocks of sheep
Wind moves everywhere
6 10,8-13,8 39-49 22-27
Strong breeze (12) (44) (25) Wind begins to Large waves, foam and
sing in the wires spray.
7 13,9-17,1 50-61 28-33 Wind sings in Sea heads up, foam in
Near gale (15) (55) (31) the wires and streaks
walking a deck
against the wind
8 17,2-207 62-64 34-40 Very difficult to Higher long waves,
Gale (19) (68) (37) walk a deck foam in streaks
against the wind
9 20,8-24,4 75-88 41-47 Small damage
Strong gale (23) (81) (44) to rigging is High waves, dense
possible. foam, spray impairs
Unfixed objects visibility.
10 24,5-28,4 89-102 48-55 Considerable Very high tumbling
Storm (27) (95) (51) damage to waves, surface white
rigging is with foam, visibility
11 28,5-32,6 103- 56-63 Exceptionally high
Violent storm (31) 117 (59) Same waves, sea covered in
(110) foam, visibility
12 Свыше Свыше Свыше Air filled with spray
Harricane >33 >117 >63 Severe damage and foam, visibility
Code. Table 3. Sea Surface State (MS).
Number Indicators to define sea surface state
(number of wave degree).
0 Sea surface is calm glassy
1 Ripple; small wave crests appear.
2 Small wave crests begin to break,
however foam, which is generated, is not
white but glassy.
3 Small waves are clearly visible, crests of
some of them break forming here and
there white froth – flocks of sheep.
4 Waves take a well-defined form, flocks of
sheep are formed everywhere.
5 Crests of considerable height appear wind
begins to tear foam away from wave
6 Crests outline long streaks of wind
7 Long streaks of foam torn off by wind
cover wave slopes and in places reach
8 Wide streaks of foam cover wave slopes
making sea surface white. Only here and
there in wave troughs there are areas free
9 Sea surface is covered with a thick layer
of foam, air is full of water spray, and
visibility is affected considerably.