Sea State and Boundary Layer Physics of the Emerging Arctic Ocean Office of Naval Research, Code 32, Arctic and Global Prediction, Department Research Initiative Inves&gators:  J.  Thomson,  V.  Squire,  S.  Ackley,  E.  Rogers,  Y.  Fan,  A.  Babanin,  P.  Guest,  T.  Maksym,  P.  Wadhams,  S.  Stammerjohn,  C.  Fairall,  O.  Persson,    

 M.  Doble,  H.  Graber,  H.  Shen,  J.  Gemmrich,  S.  Lehner,  B.  Holt,  T.  Williams,  J.  Bidlot,  F.  Girard-­‐Ardhuin,  W.  Perrie,  J.  Brozena    Program  managers:  Mar&n  Jeffries,  ScoR  Harper  

Mo&va&on   Climatology  &  Models   Measurements  

 hRp://www.apl.washington.edu/project/project.php?id=arc&c_sea_state  

 

Nome

Dutch Harbor

500 m

Ice edge deployments (buoys, AUV, UAV) Pack ice stations (on-ice array, AUV under-ice transects, LiDAR, EMI, CTDs) Transects and flux stations (Met, UAV, AUV, LiDAR, EMI, CTDs, buoys)

Underway (met tower, wave radar, underway CTD, cameras) Open water stations (mooring, buoys, CTDs, glider, AUV AUV, waveglider)

Barrow

NRL aircraft range

In  the  fall  of  2015,  a  6  week  experiment  will  be  conducted  to  measure   physical   processes   at   the   air-­‐ice-­‐ocean   boundary,  using   in  situ  and  remote  sensing  techniques  (Figure  5).    The  central   placorm  with  be   the  R/V   Sikuliaq,  which  will   transit  north  to  the  ice  edge  on  Oct  1,  and  follow  the  advancing  ice  south  (Figure  6).    

103 104 105 106 107 108

10−4

10−3

10−2

10−1

100

101

102

Fetch (scaled), g x / U2

Wave

energ

y (sc

aled),

g2 (H/4)

2 / U4

← P−M limit

iceseaswell

The  central  hypothesis  of  the  ‘Sea  State’  DRI  is  that  surface  waves  now  have  a  much  greater  role  in  the  contemporary  Arc&c   Ocean   (e.g.,   Figure   1)   and   the   dynamics   of   the  seasonal  ice  zone.    There  is  the  poten&al  for  a  feedback,  as  wave   genera&on   is   controlled   by   the   amount   of   open  water   fetch   (Figure   2).   At   smaller   scales,   waves   and   ice  interact   to   aRenuate   and   scaRer   the   waves   while  simultaneously  fracturing  ice  into  ever  changing  floe  sizes.  The  changing  seasonal  ice  zone  presents  new  opportuni&es  and   new   problems.   Naviga&on   and   other   mari&me  ac&vi&es  become  possible,  but  waves,  storm  surges,  air-­‐sea  fluxes  and  coastal  erosion  will  likely  increase.  

2002-2014 mean: yd 299 (Oct 26)

1989-2001 mean: yd 278 (Oct 5) 1979-1988 mean:

yd 266 (Sep 23)

Thomson  &  Rogers,  2014,  GRL  

Figure  1.    WAVEWATCH  3  model  hindcast  of  waves  during  a  storm  in  Sept  2012.    The  storm  coincided  with  

the  minimal  ice  extent  on  record.      

Figure  2.  Measured  wave  energy  and  open  water  distance,  scaled  by  wind  speed,  during  

the  open  water  season  of  2012.  

The  DRI  will  focus  on  arc&c  condi&ons  during  the  late  summer  and  early  autumn,  especially   the   freeze-­‐up   of   the   Beaufort   and   Chukchi   seas,   to   capture   the  strongest   storms   and  maximum  open  water.     The   fall   ice   advance   now   occurs  much  later  than  in  previous  decades  (Figure  3).    To  understand  the  implica&ons  of  this  shii,  the  WAVEWATCH3  model  has  recently  been  upgraded  with  several  different   ice   algorithms.     These   can   be   applied   in   a   hindcast   (e.g.   Figure   4)   or  forecast   mode   to   quan&fy   the   related   changes   in   the   wave   climate.   Results  suggest  that  stronger  wave  energy  flux  events  have  occurred  in  recent  years.  

Figure  3.    Date  of  seasonal  transiIon,  when  ice  begins  to  advance  in  the  Chukchi-­‐Beaufort  Sea,  by  year.    Data  from  NSIDC.  

Figure  4.    Daily  Ime  series  of  wave  energy  arriving  at  ice  edge  for  a  selecIon  of  recent  years.    Results  from  WAVEWATCH  3.    

Figure  6.  Cruise  track  for  the  R/V  Sikuliaq  during  the  fall  2015  field  campaign.  

Figure  5.    SchemaIc  of  the  fall  2015  field  campaign.    

Stammerjohn  et  al.,  2012;  GRL,  updated