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