De c a da l Wa ve Va ria b ility in the e a ste rn No rth Atla - - PowerPoint PPT Presentation

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De c a da l Wa ve Va ria b ility in the e a ste rn No rth Atla ntic a sso c ia te d with the NAO Ha rrif Sa nto Pa ul T a ylo r Ric ha rd Gib so n Mo tiva tio n Pub lishe d o b se rva tio ns sho w No rth Atla ntic wa s g e tting ro ug

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SLIDE 1

De c a da l Wa ve Va ria b ility in the e a ste rn No rth Atla ntic a sso c ia te d with the NAO

Ha rrif Sa nto Pa ul T a ylo r Ric ha rd Gib so n

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SLIDE 2

Mo tiva tio n

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Ref: Carter, D., and L. Draper (1988), Has the north-east Atlantic become rougher?, Nature, 332, 494.

Pub lishe d o b se rva tio ns sho w No rth Atla ntic wa s g e tting ro ug he r o ve r 1960s – 1990s.

  • due to c lima te c ha ng e ?

? ? ? ?

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SLIDE 3

Que stio ns

  • I

s the re a n a ve ra g e wa ve c lima te a t a pa rtic ula r lo c a tio n?

  • Are the wa ve s o ve r the la st 25 – 50 ye a rs a re lia b le g uide to the ne xt 25
  • r 100 ye a rs?
  • T

he a va ila b le wa ve re c o rds a re to o sho rt, is the re a wa y to infe r a lo ng e r time histo ry fo r wa ve c lima te b a c k to the pa st (o ve r 400 ye a rs)?

3

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SLIDE 4

NAO a nd o the r two mo de s

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Re f: Mo o re , G., I . Re nfre w, a nd R. S. Pic ka rt (2013), Multide c a da l mo b ility o f the No rth Atla ntic Osc illa tio n, Jo urna l o f Clima te , 26(8), 2453–2466.

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SLIDE 5

Ma p o f the lo c a tio ns

5

  • Hindc a st da ta : NORA10 fo r a ll

fro m 1958 – 2011 (54 ye a rs)

  • All da ta c o nta in ,

, a nd

  • sa mple d e ve ry 3 ho urs.
  • Da ta

a lso c o nta in wa ve dire c tio n, wind spe e d a nd wind dire c tio n, a nd a split o f to ta l wa ve s into swe lls a nd wind wa ve s.

  • Ana lysis is pre se nte d
  • n

to ta l wa ve s.

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SLIDE 6

Mo de l/ b uo y c o mpa riso ns

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  • Sho wn he re fo r Ha lte nb a nke n
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SLIDE 7

Wa ve po we r e stima te

  • No te the use o f

ra the r tha n ( ~1.2 ).

  • Winte r we a the r is wo rst, summe r ra the r b e nig n.
  • We lo o k a t to ta l a ve ra g e po we r ye a r b y ye a r (with ye a r running fro m

summe r to summe r, a vo id splitting winte rs).

  • I

n the ne a r future , se a so na l va ria tio n c a n b e inc lude d fo r mo nthly wa ve po we r va ria b ility.

7

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SLIDE 8

Co rre la tio n with NAO a nd o the r mo de s

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  • Pre dic to r mo de l b a se d o n line a r re g re ssio n using c lima te indic e s.
  • I

ndic e s o b ta ine d fro m Clima te Pre dic tio n Ce nte r (NOAA, a va ila b le fro m 1950 o nwa rds).

  • Mo de l is tra ine d
  • ve r the

pe rio d

  • f hindc a st da ta

b y minimising the va ria nc e .

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SLIDE 9

Co rre la tio n with NAO a nd o the r mo de s

9

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SLIDE 10

Co rre la tio n with NAO a nd o the r mo de s

10

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SLIDE 11

Co rre la tio n with NAO a nd o the r mo de s

11

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SLIDE 12

Ang ula r pa rtitio ning a t F

  • rtie s

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205°-5°

No nline a r pre dic to r mo de l fo r b e tte r c o rre la tio n fo r lo c a tio ns in No rth Se a .

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SLIDE 13

Pro xy inde x b a se d o n pre ssure fie lds fo r re c o nstruc tio n prio r to 1950

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Re f: L ute rb a c he r, J., E . Xo pla ki, D. Die tric h, R. Ric kli, J. Ja c o b e it, C. Be c k, D. Gya listra s, C. Sc hmutz, a nd H. Wa nne r (2002), Re c o nstruc tio n o f se a le ve l pre ssure fie lds o ve r the E a ste rn No rth Atla ntic a nd E uro pe b a c k to 1500, Clima te Dyna mic s, 18 (7), 545–561.

  • Using re c o nstruc te d winte r pre ssure fie lds fro m L

ute rb a c he r (2002).

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SLIDE 14

Re c o nstruc te d o c e a n wa ve po we r a t Orkne y

14

25% va ria tio n

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SLIDE 15

T he M4 wa ve po we r ma c hine – Pro f. Pe te r Sta nsb y

  • T

hre e -flo a t syste m se pa ra te d b y ha lf a wa ve le ng th.

  • Bro a db a nd fre q ue nc y re spo nse in irre g ula r wa ve s.

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http:/ / www.ma c e .ma nc he ste r.a c .uk/

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SLIDE 16

Re c o nstruc te d pra c tic a l wa ve po we r e xtra c te d b y the M4 ma c hine a t Orkne y

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10% va ria tio n

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SLIDE 17

E stima ting 100-ye a r sto rm se ve rity

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  • Via the mo st pro b a b ly ma ximum individua l

wa ve he ig ht in a sto rm, (se e T ro ma ns a nd Va nde rsc hure n 1995).

  • Pe a ks-o ve r-thre sho ld,

thre sho ld va lue = 1000 la rg e st sto rms fo r 54 ye a rs o f da ta , whic h c o rre spo nds to a b o ut 20 sto rms pe r winte r, ro ug hly 1-2 pe r we e k.

  • Ma ximum like liho o d me tho d a s e stima to r

fo r e xpo ne ntia l-type ta il.

  • F

ive -ye a r sliding windo w a na lysis to o b ta in te mpo ra l va ria b ility o f .

Re f: T ro ma ns a nd Va nde rsc hure n (1995), Re spo nse b a se d de sig n me tho d in the No rth Se a : Applic a tio n

  • f a ne w me tho d, in Offsho re T

e c hno lo g y Co nfe re nc e , OT C 7683, Ho usto n.

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SLIDE 18

Co rre la tio n with the te le c o nne c tio ns

18

  • Sa me

pre dic to r mo de l a s the me a n wa ve c lima te c o rre la tio n, e xc e pt a ll NAO, E A a nd SCA indic e s a re lo w pa ss filte re d (mo ving a ve ra g e ) o f 5 ye a rs.

F ive -ye a r sliding windo w:

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SLIDE 19

Re c o nstruc tio n o f e xtre me a nd me a n wa ve c lima te

19

F

  • r o pe n No rth-Atla ntic

lo c a tio ns: va ria tio ns o f me a n a nd e xtre me wa ve c lima te a re c o mpa ra b le .

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SLIDE 20

Re c o nstruc tio n o f e xtre me a nd me a n wa ve c lima te

20

F

  • r No rth Se a lo c a tio ns:

va ria tio ns o f me a n a nd e xtre me wa ve c lima te a re diffe re nt.

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SLIDE 21

I n c o nc lusio n:

  • I

s the re a n a ve ra g e wa ve c lima te a t a pa rtic ula r lo c a tio n?

Yes, but the aver age has to be oversever al decades as ther e is a lot

  • f decadal var

iability (in gener al).

  • Are the wa ve s o ve r the la st 25 – 50 ye a rs a re lia b le g uide to the ne xt 25
  • r 100 ye a rs?

Maybe? Depending on what the NAO is doing.

  • T

he a va ila b le wa ve re c o rds a re to o sho rt, is the re a wa y to infe r a lo ng e r time histo ry fo r wa ve c lima te b a c k to the pa st (o ve r 400 ye a rs)?

Yes, by establishing a str

  • ng link with the NAO.

21

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SLIDE 22

Ac kno wle dg e me nt

F

  • r mo re info rma tio n:
  • Sa nto , H., T

a ylo r, P. H., Wo o lling s, T ., & Po ulso n, S. (2015). De c a da l wa ve po we r va ria b ility in the No rth‐E a st Atla ntic a nd No rth Se a .

Ge o physic alRe se arc h L e tte rs, 42(12), 4956-4963.

  • Sa nto , H., T

a ylo r, P. H., Wo o lling s, T ., & Gib so n, R. (2015). De c a da l va ria b ility o f e xtre me wa ve he ig ht a s a me a sure o f sto rm se ve rity in the No rth‐E a st Atla ntic a nd No rth Se a . Ge o physic alRe se arc h L

e tte rs (submitte d).

  • Sa nto , H., T

a ylo r, P. H., E a to c k T a ylo r, R. a nd Sta nsb y, P. (2015). De c a da l Va ria b ility o f Wa ve Po we r Pro duc tio n in the No rth-E a st Atla ntic a nd No rth Se a fo r the M4 Ma c hine . Re ne wable E

ne rgy (submitte d).

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We tha nk BP Sunb ury fo r pro viding the wa ve da ta a nd a c kno wle dg e suppo rt fro m UKE PSRC thro ug h pro je c t SMART Y.