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FFORECASTINGORECASTING DDANGEROUSANGEROUS
SSEAEA--SSTATES:TATES:
BEYOND HBEYOND HSS AND TAND TPPJaak MonbaliuJaak Monbaliu andand
Alessandro ToffoliAlessandro ToffoliHydraulics LaboratoryHydraulics Laboratory
Department of Civil Engineering, K.U.Department of Civil Engineering, K.U. LeuvenLeuven
Contact:Contact: jaakjaak..monbaliumonbaliu@@bwkbwk..kuleuvenkuleuven.ac.be.ac.be
CLIMARCLIMAR--IIII
Second JCOMM Workshop on Advances MarineSecond JCOMM Workshop on Advances Marine ClimatologyClimatology
Brussels, Belgium, 17Brussels, Belgium, 17--22 November 200322 November 2003
Forecasting Dangerous Sea-States 2
CCONTENTSONTENTS
1.1. INTRODUCTIONINTRODUCTION•• The E.U. Project MaxWaveThe E.U. Project MaxWave
2.2. DANGEROUS SEADANGEROUS SEA--STATESSTATES•• The New Year’s WaveThe New Year’s Wave
•• Worldwide ship accidents due toWorldwide ship accidents due toheavy seasheavy seas
•• Casualties & seaCasualties & sea--statesstates
3.3. GLOBAL MAPSGLOBAL MAPS•• Wave ParametersWave Parameters
•• Ocean CurrentsOcean Currents
4.4. CONCLUSIONSCONCLUSIONS
Forecasting Dangerous Sea-States 3
• Forecasts and Statistics of Rogue Waves
• Investigation of Accidents due to Rogue Waves
EU Project MaxWave
http://w3g.gkss.de/projects/maxwave/
0 200 400 600 800 1000 1200-10
-5
0
5
10
15
20
time [s]
heig
ht [s
]
Partners:• GKSS• DLR• DNMI• DNV• IST• K.U. Leuven• MeteoF• OSW• TuB• UKMet• IBWPAN
Forecasting Dangerous Sea-States 4
!(
0°0'0"E
0°0'0"E
10°0'0"E
10°0'0"E
50°0'0"N 50°0'0"N
60°0'0"N 60°0'0"N
70°0'0"N 70°0'0"NNNEWEW YYEAR’SEAR’S WWAVEAVE
DraupnerDraupner5858oo 10’ N10’ N0202oo 30’ E30’ E
0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0- 1 0
- 5
0
5
1 0
1 5
2 0
t im e [s e c ]
elev
atio
n [m
]
D r a u p n e r O il F ile d - 1 9 9 5 / 0 1 0 1 1 5 . 2 0 - 1 5 . 4 0 U T C
• 1ST January 1995
HS = 11.93 m
TP = 16.84 s
HHmaxmax = 25= 25 mm
Acknowledgments: www.statoil.com
Forecasting Dangerous Sea-States 5
0 50 100 0
2
4
6
8
10
Time [h]
H m
0 [m]
0 50 100 0
0.01
0.02
0.03
0.04
0.05
S [-
]
00 01.4 mH m =
210
2
−
=m
S
TgH
Sπ
0
2
4
6
8
10
12
-10 -5 0 5 10
50
55
60
65
70
longitude[deg]
latit
ude[
deg]
Significant Wave Height [m] 1995/01/01 15:00 UTC
• At the peak of the storm:
Forecasting Dangerous Sea-States 6
SSHIPHIP AACCIDENTSCCIDENTS
Five years of ship accidents (1995-1999)due to bad weather werecollected from the Lloyd’s Marine Information Service (LMIS) andLloyd’s Casualty report.
Forecasting Dangerous Sea-States 7
Legendship_density
0.09
0.10 - 6.78
6.79 - 13.47
13.48 - 26.86
26.87 - 53.64
53.65 - 147.36
147.37 - 1,713.77 More than 4 ship accidents per MAR zone
The ship density is computed assigning index of 100 if 8 callsigns are counted in an area of 500 X 500 km2 per day. A callsign is the name that a ship uses for radio transmissions. Adatabase containing ship tracks was kindly provided by JCOMMOPS.
SSHIPPINGHIPPING AACTIVITIES ANDCTIVITIES AND AACCIDENTSCCIDENTS
Forecasting Dangerous Sea-States 8
0 50 100 150 6
8
10
12
14
Time S
ea-S
tate
s
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.4 0.3 0.2 0.1 Hz
0o
90o
g p
CCASUALTIES &ASUALTIES & SSEAEA--SSTATETATE
1. Ship accidents Database1. Ship accidents Database•• Location:Location:
–– MAR zonesMAR zones
–– Latitude & LongitudeLatitude & Longitude
•• Time:Time:
–– Day of the events (local time)Day of the events (local time)
•• 270 Accidents analyzed270 Accidents analyzed
2. Sea2. Sea--State at the time of theState at the time of theaccidents:accidents:
•• ECMWFECMWF –– ERA40ERA40 (grid =(grid = 1.51.5°°X1.5X1.5°°))
•• Integrated parameters before and atIntegrated parameters before and atthe time of the casualtiesthe time of the casualties
Forecasting Dangerous Sea-States 9
WWAVEAVE PPARAMETERSARAMETERS
00 01.4 mHm =
202
gTHS mπ=
0
110 m
mTm
−− =
{ })(max2
ωωπS
TP =
total
seawind
mm
0
0
( ) directionwavemeanϑ
0.10.20.30.4 Hz
0o
90o••Total SeaTotal Sea
••Wind SeaWind Sea
••SwellSwell
Parameters were retrieved for:
A space window of 3°x3° around thecasualty
A time window involving 2 daysbefore, the day of the casualty andthe day after (UTC time)
Forecasting Dangerous Sea-States 10
0 2 4 6 8 10 12 0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
H m0 [m]
Nor
mal
ized
n
o of
acc
iden
ts
Maximum Hm0 [m]
0 10 20 30 0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
T P [s ]
Nor
mal
ized
n
o of
acc
iden
ts
0 10 20 30 0
0.02
0.04
0.06
0.08
0.1
U 10 [m/s ]
Nor
mal
ized
n
o of
acc
iden
ts
TP [s]
10 m Wind Speed [m/s]
Hm0 < 4 m for2 accidentsout of 3
At thetime ofmax Hm0
At thetime ofmax Hm0
SSEAEA--SSTATESTATESMaximum significant wave heightrecorded within 3 days (the daybefore, the day of the casualtiesand the day after) and the relatedpeak period and wind speed
Forecasting Dangerous Sea-States 11
WWAVEAVE SSTEEPNESSTEEPNESS
0 0.02 0.04 0.06 0
10
20
30
40
50
60 Wave S teepness
S [-]
Nor
mal
ized
n
o of
acc
iden
ts
0 0.02 0.04 0.06 0.08 0
0.2
0.4
0.6
0.8
1
S [-]
( m 0
Sw
ell )
/ ( m
0
Tot
al )
0 5 10 15 0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
(Ma ximum) H m0 [m]
(Max
imum
) S [-
]
From Pierson-Moskowitzspectral formulation: S = 0.04 (const.)
S > 0.035 for 2 accident out of 5
210
2
−
=m
s
gTHS π
Max Steepness vs. Max Hm0
M0 swell/M0 totvs. Steepness
Forecasting Dangerous Sea-States 12
Histogram of for accidents
0 0.2 0.4 0.6 0.8 1 0
0.5
1
1.5
2
s in( θ )
Nor
mal
ized
n o o
f acc
iden
ts
CCROSSINGROSSING SSEASEAS
8.02.00
0 ≤≤total
seawind
mm
swellwindsea ϑϑϑ −=
( ) 8660.0sin >ϑ
( ) 7071.0sin >ϑ
)4590)(( oo ±−+=ϑ
*)3090)(( oo ±−+=ϑ
Crossing Seas
1.
characterized by:
Assumptions
8.02.00
0 ≤≤total
seawind
mm
2.
( )ϑsin
(40% of the events)
Forecasting Dangerous Sea-States 13
SSPECTRALPECTRAL DDIRECTIONALIRECTIONAL WWIDTHIDTH
20 ≤≤ σ
0 = unidirectional spectrum
= uniform spectrum2
0 0.2 0.4 0.6 0.8 1 0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
| s in( θ ) | [-]
σ [-]
Directional information of thedifferent wave components canbe obtained from the circularstandard deviation (σ).
( ) ( ) ( )fEfDfF ϕϕ ,, =
Forecasting Dangerous Sea-States 14
Location: West of Shetland IslesTime: 9th November 1998, 22:00 UTCDamage: an area of the bow, 20 m abovethe water line, was pushed in by 0.25m (Gorf et al. 2000, Proc. Int. Conf.“Rogue Wave 2000”).
SSCHIEHALLIONCHIEHALLION FPSOFPSO
Acknowledgments: www.offshore-technology.com
Forecasting Dangerous Sea-States 15
0 20 40 60 80 0
0.2
0.4
0.6
0.8
1
m 0
win
d se
a /
m 0
tot [-
]
0 20 40 60 80 0.4
0.6
0.8
1
1.2
1.4
σ [-]
Time [h]
0 20 40 60 80 2
4
6
8
10 H
m0 [m
]
Time [h]0 20 40 60 80
0.01
0.02
0.03
0.04
0.05
S [-
]
0 20 40 60 80 8
9
10
11
12
13
T m-1
0 [s]
Time [h] 0 20 40 60 80
5
10
15
20
25
30
U 10
[m/s
]
Sea-state from ECMWF-ERA40database. Period between1998/11/07 and 1998/11/10
Rapid developments play an important role
Hm0 and S Tm-10 and U10
M0 wind sea/M0 tot and σ
Forecasting Dangerous Sea-States 16
2. Wave Steepness
1. Significant Wave Height
3. Directional Width
Wave Steepness0.002 - 0.007
0.008 - 0.016
0.017 - 0.026
0.027 - 0.031
0.032 - 0.036
0.037 - 0.045
0.046 - 0.060
GLOBAL DISTRIBUTIONGLOBAL DISTRIBUTION
Significant Wave Height [m]0.07 - 1.64
1.65 - 2.55
2.56 - 3.50
3.51 - 4.69
4.70 - 6.18
6.19 - 8.57
8.58 - 10.64
Directional Width0 - 0.26
0.261 - 0.52
0.521 - 0.62
0.621 - 0.74
0.741 - 0.87
0.871 - 1.16
1.161 - 1.414
Forecasting Dangerous Sea-States 17
OOCEANCEAN CCURRENTSURRENTS
Warm Currents
Cold Currents
Accidents
Strong ocean currents:
•Agulhas Currents (~ 2 m/s)
•Kuroshio Currents (~ 1.6 m/s)
Forecasting Dangerous Sea-States 18
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110°0'0"E
110°0'0"E
120°0'0"E
120°0'0"E
130°0'0"E
130°0'0"E
140°0'0"E
140°0'0"E
20°0
'0"N
20°0
'0"N
30°0
'0"N
30°0
'0"N
40°0
'0"N
40°0
'0"N
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110°0'0"E
110°0'0"E
120°0'0"E
120°0'0"E
130°0'0"E
130°0'0"E
140°0'0"E
140°0'0"E
20°0
'0"N
20°0
'0"N
30°0
'0"N
30°0
'0"N
40°0
'0"N
40°0
'0"N
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110°0'0"E
110°0'0"E
120°0'0"E
120°0'0"E
130°0'0"E
130°0'0"E
140°0'0"E
140°0'0"E
20°0
'0"N
20°0
'0"N
30°0
'0"N
30°0
'0"N
40°0
'0"N
40°0
'0"N
SteepnessSteepness
Significant wave heightSignificant wave height
Directional widthDirectional width
SEASEA--STATES ALONG THESTATES ALONG THEKUROSHIO CURRENTSKUROSHIO CURRENTS
Wave Steepness0.002 - 0.007
0.008 - 0.016
0.017 - 0.026
0.027 - 0.031
0.032 - 0.036
0.037 - 0.045
0.046 - 0.060
Significant Wave Height [m]0.07 - 1.64
1.65 - 2.55
2.56 - 3.50
3.51 - 4.69
4.70 - 6.18
6.19 - 8.57
8.58 - 10.64
Directional Width0 - 0.26
0.261 - 0.52
0.521 - 0.62
0.621 - 0.74
0.741 - 0.87
0.871 - 1.16
1.161 - 1.414
Forecasting Dangerous Sea-States 19
CCONCLUSIONSONCLUSIONS
• Wave fields were used in the analysis of accidents due to bad weather.
• The classical spectral parameters (e.g. Hm0) are not sufficient. (Apparently rather low sea-state were found)
• Additional parameters are needed:– Directional information (e.g. crossing seas)– Rapid developments– Environmental factors (e.g. ocean currents)
• Ships react differently to a certain sea-state and hence an interpretation of wave forecast will be needed for each type of ship and possibly for each individual ship.
• BB for ships
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