SWARP: WP2, wave modelling Fabrice Ardhuin, Mickael Accensi, Pierre Queffeulou, Fanny Ardhuin (Ifremer) Fabrice Collard (Oceandatalab) Aron Roland (TU Darmstadt) http://wwz.ifremer.fr/iowaga http://www.previmer.org/previsions/vagues

Outline 1. Building on other projects and developments : IOWAGA (ERC), Waves-NOPP (U.S. ONR) ... 2. Specific developments for SWARP: Numerics (implementation of new model version) Development of parameterizations: - friction below the ice - shorelines & ice-edge reflections - scattering Estimation of energy & momentum fluxes 3. Hindcasts & forecasts

Building on other projects and developments SWARP Kick-off, February 3, 2014 1 Building on other projects and developments wwz.ifremer.fr/iowaga

1. a multi-parameter global wave hindcast The ERC-funded IOWAGA project integrates - Coastal hydrodynamics - Air-sea fluxes - Remote sensing - Microseisms into a single consistent wave modelling system. → new version 4.18 of WAVEWATCH III (distributed by NOAA/NCEP) → hindcast database, >40 different parameters (http://tinyurl.com/iowagaftp) - Results from global multigrid (1993-2013) : GLOBAL : (30' resolution)... up to 80°N only PACE (10'): East Pacific (Alaska to Peru), with Hawaii & ... ATNW (10'): U.S. East coast + Gulf of Mexico ATNE (10'): Iceland to Morocco (6'). NC (3'): New Caledonia & Vanuatu (3') CRB (3'): Lesser Antilles (Puerto Rico to Venezuela, 3') 1 or 2 runs (with CFSR and / or ECMWF op. Winds) Recent runs : > 9000 full spectra output (along all shorelines + others) + finite element zooms in coastal areas

1. a multi-parameter global wave hindcast IOWAGA hindcast particularly focused on - better swells (swell dissipation based on Ardhuin et al. GRL 2009) - better high frequency energy ( → Stokes drift, mss, see JPO 2009, 2010) - better directional parameters (Ardhuin & Roland JGR 2012, Ardhuin et al. JASA 2013) important for acoustic and seismic noise General validation : Rascle & Ardhuin (Ocean Modelling 2013) Here are a few plots with data from http://tinyurl.com/iowagaftp … but GLOBAL : (30' resolution)... up to 80°N only

Specific developments for SWARP SWARP Kick-off, February 3, 2014 2 Specific developments for SWARP wwz.ifremer.fr/iowaga

2. developments for SWARP Extension to Arctic : just one more grid ? - 12 km polar grid, same as NSIDC or Ifremer-CERSAT sea ice products (concentration and drift from SSM/I + ERS / QuikSCAT / ASCAT) first tests : forced by global grid - next steps : Two-way nested in multigrid Bathymetry for new grid (IBCAO) Possible higher resolution if needed (12 km Arctic is less expensive that global hindcast)

2. developments for SWARP Parameterizations: Implementation of shoreline reflection on curvilinear grid - could be added for ice edge … Implementation of viscous & turbulent friction under the ice : Generalization of Liu & al. (JGR 1991) following work on swell dissipation (Ardhuin & al. 2009, Rascle & Ardhuin 2013, Perignon et al., submitted) - non linear dissipation rate for turbulent cases, no “eddy viscosity” - transition threshold (laminar to turbulent), random waves → smoothing Scattering term: to be defined Solution method taken from bottom topography scattering (Ardhuin & Magne 2007)

2. developments for SWARP It runs! … Example of wave data retrieval from SAR imagery (2011/03/04 9h14, Envisat) sea ice water WW3 results : Wave heights from SAR (not adapted yet to sea ice)

Hindcasts and forecasts SWARP Kick-off, February 3, 2014 3 Hindcasts and forecasts wwz.ifremer.fr/iowaga

2. Tests with different forcing products Sept 16th : Yearly sea ice extent minimum Sept 17th : Freeze observed by scatt., not by radiometer Sept 18th : Freeze observed by both sensors Concentration from radiometer Standard deviation of backscatter data Concentration from radiometer Concentration from radiometer Interest of the use of both scatterometer and radiometer data for MIZ monitoring Scatterometer sensor can detect the very first stage of sea ice

3. Hindcasts & forecasts 2008-2015: Arctic hindcasts - multi-grid system including 12 km grid - ECMWF winds + ?? ice - higher resolution mesh focusing on ice edge ? 2016: forecasts Deliverables: Jan 2015 : First version of wave and sea ice models. Data exchanged between the partners, deliverable 2.1 “First wave model results covering the MIZ” Jan 2016 : Validation completed. Data flows integrated to NavPlanner, deliverable 2.2 “Upgraded wave model” July 2016 : deliverable 2.3 “Forecast and hindcast simulations for demonstration”

3. Validation of the wave model a) wave parameters Generic validation: Altimeters (Hs & mss ): in ice-free water Permanent buoys: general context (Iceland + Barents Sea ) WIFAR 2012 + other field data validation: Detailed estimation of spectra, specific validation of wave attenuation rates SAR-derived attenuation rates rms error for Hs (%) Ardhuin et al. 2010 (Prévimer) Ardhuin et al. 2010

1. a multi-parameter global wave hindcast The ERC-funded IOWAGA project integrates - Coastal hydrodynamics - Air-sea fluxes - Remote sensing - Microseisms into a single consistent wave modelling system. → new version 4.18 of WAVEWATCH III (distributed by NOAA/NCEP) → hindcast database, >40 different parameters (http://tinyurl.com/iowagaftp) - Results from global multigrid (1993-2013) : GLOBAL : (30' resolution)... up to 80°N only PACE (10'): East Pacific (Alaska to Peru), with Hawaii & ... ATNW (10'): U.S. East coast + Gulf of Mexico ATNE (10'): Iceland to Morocco (6'). NC (3'): New Caledonia & Vanuatu (3') CRB (3'): Lesser Antilles (Puerto Rico to Venezuela, 3') 1 or 2 runs (with CFSR and / or ECMWF op. Winds) Recent runs : > 9000 full spectra output (along all shorelines + others) + finite element zooms in coastal areas

Scattering in the MIZ inferred from seismic/acoustic noise ? AGU meeting, San Francisco, December 2013 3 Scattering in the MIZ inferred from seismic/acoustic noise ? wwz.ifremer.fr/iowaga

k2 K k1 3. Scattering and noise : theory Hasselmann (1963) : nearly opposing waves generate seismic noise k2 K k1 Movie of sea surface elevation Z = Z1 + Z2 Any 2nd order quantity like Z2 will thus contain K = k1 ± k2 and f = f1 ± f2 Higher order interactions : K = k1 ± k2 ± k3 and f = f1 ± f2 ± f3 … and so on … The interaction of k1 and k2 gives noise at K = k1 + k2 and f = f1 + f2 Resonant interaction if 2 pi f / K = Cs , the phase speed of one seismic mode. For any f, this selects K.

5.1 Validation of the wave model a) wave parameters Generic validation: Altimeters (Hs & mss ): in ice-free water Permanent buoys: general context (Iceland + Barents Sea ) WIFAR 2012 + other field data validation: Detailed estimation of spectra, specific validation of wave attenuation rates SAR-derived attenuation rates rms error for Hs (%) Ardhuin et al. 2010 (Prévimer) Ardhuin et al. 2010

FF 3. Scattering and noise : When do we get noise ? From wave spectrum to acoustic or seismic noise : deep water waves : noise source proportional to Noise is linked to waves in opposite directions. Loud sources in MIZ ?? Example of seismic records around the Pacific due to « swell collision » : FF Obrebski et al. (GRL 2012)

3. Scattering and noise : Different modes Different modes : - seismic waves (Rayleigh or body waves) → can be recorded on land ! - acoustic gravity waves (evanescent : local sea state) 100 to 500 m depth Evanescent modes dominate (see Cox & Jacobs GRL 1989)

Example of a noise event ... 3. Scattering and noise : Example of a noise event ... KBS Greenland DBG Iceland SCO

Example of a noise event ... 3. Scattering and noise : Example of a noise event ... Modeled seismic sources Hs Seismic spectra at SCO

1. Bottom friction Cliffs north of Jan Mayen : strong wave reflection (another day)...

Perspectives 4 AGU meeting, San Francisco, December 2013 wwz.ifremer.fr/iowaga

Anybody has a mooring out there? - Introducing wave dissipation and scattering in the MIZ : Verification of dissipation with SAR-derived Hs and Tm02 Scenarii for scattering : how large can it be given seismic records ? - Deploying pressure sensors 100 to 500 m from the surface? Direct measurements of evanescent modes → measurement of I(f) integral, a very strong constraint on scattering strength. Anybody has a mooring out there? Les MNT dans la modélisation côtière - Journée Valor'IG09 It works ! Data from SBE26 in 100 m depth (Ardhuin & al. JASA 2013)