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  • Regional tidal correction

    CP4O final meeting

    02/07/2014

  • NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    Regional tidal correction

    ! Tides repartition over the global ocean ! In the open ocean

    Low amplitudes, large spatial scales (several hundreds/thousands of km)

    Not the main oceanic process

    ! On the continental shelf Tidal amplitudes increase (up to meters), small spatial scales (a few tens of km)

    Often prevails over the rest of the ocean dynamics

    02/07/2014 2

    FES2012 M2 wave amplitude (cm)

  • Regional tidal correction

    ! Tidal corrections for altimetry data ! Global models

    Distributed in the altimeter products: FES2004, FES2012, (FES2014, coming soon)

    GOT4.7

    Other models, not distributed in the L2/GDR altimeter products: DTU10, EOT11a, TPXO7.2

    ! Grid resolution From 1/2 degree (~50km) for GOT to 1/16 degree (~7km) for FES2012

    Too coarse to catch the non-linear tidal processes on the shelves

    ! Errors About 1-2cm in the open ocean

    Locally up to several tens of centimeters in the coastal zones

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    3

  • Regional tidal correction

    ! Motivations for regional tidal modelling ! Bathymetry

    Badly known in some regions

    Global implies impossible to check everywhere carefully

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    4

    Bathymetry 2010 vs XBTs depth

    Bathymetry 2009 vs XBTs depth

    NEA (optimal) COMAPI

    Bathymetry Version-2009

    M2

    NEA (hydrodynamic)

    Bathymetry Version-2009

    M2

    NEA (hydrodynamic)

    Bathymetry Version-2010

    M2

  • Regional tidal correction

    ! Motivations for regional tidal modelling ! Higher spatial resolution to catch the small-scale tidal structures

    Global models: 1/2(~50km), 1/4(~25km), 1/8(~12,5km)

    Typical size of M4 structures : a few tens of kilometers

    Not accurate enough to well represent the complex tidal dynamics and the high spatial variability of the process in the coastal zones

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    5

    Extract of FES2012 mesh

    Finite elements size: Deep ocean:

    75 km Shallow waters: 7.5 km

    NEA regional mesh

    Finite elements size: Deep ocean: 20 km Shallow waters: 500 m

  • Regional tidal correction

    ! Motivations for regional tidal modelling ! Regional tuning of the hydrodynamic model

    Global model: one global value for each parameter (ex: bottom friction coeff.)

    Regional model: one value adapted to the zone

    Better modelling of the local physics

    ! Direct compatibility with global models via the boundary conditions

    Regional models can be patched in compatible global models

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    6

  • Regional tidal correction

    ! Motivations for regional tidal modelling ! Regionally tailored assimilation experiments

    Number of assimilated observations directly linked to computing limitations (RAM)

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    7

    Assimilated observations in FES2012 AVISO data: crossover points offshore

    + alongtrack data in the coastal areas

    Assimilated observations in the NEA model TP/J1 CTOH coastal data

    + Tide gauges

    Global Regional

  • Regional tidal correction

    ! Regional tidal modelling applications ! COMAPI regional tidal models (NEA and MED) for coastal altimetry

    CNES/NOVELTIS/LEGOS project (2009-2010)

    Main improvements (RMS reduction): Celtic Sea, Irish Sea, English Channel

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    8

    COMAPI/FES2004

    Diff. of altimeter SLA RMS Diff. of altimeter SLA RMS

    COMAPI/GOT4.7

  • Regional tidal correction

    ! Specific processing for CP4O ! Computation of the COMAPI tidal correction over NEA for CryoSat-2

    Prediction of the tide at each location and date of the CryoSat-2 measurements

    From January 2011 to January 2013

    Compatible with FES2004 ocean tide and loading tide.

    Evaluation performed by CLS, in collaboration with NOVELTIS (see T. Moreaus presentation).

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    9

  • Regional tidal correction

    ! Other applications ! TIPS: Tidal Prediction Service - http://tips.noveltis.com/

    Maintained and developed on NOVELTIS funds

    Global and regional tidal modelling: elevations and currents

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    10

  • Regional tidal correction

    ! Other applications ! TIPS: Tidal Prediction Service - http://tips.noveltis.com/

    Various applications and end-users:

    Boundary conditions for ocean modelling

    Ocean model validation

    Offshore activities

    Marine energy site assessment

    02/07/2014 NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    11

    Average Power Density (kW/m)

    http://energie.edf.com

  • NOV-7085-SL-4084 NOVELTIS 2014. This document is the property of Noveltis, no part of it shall be reproduced or transmitted without the express prior written autorisation of Noveltis.

    Regional tidal correction

    ! New developments and Perspectives ! Continuous update/development of tidal atlases

    TIPS-NEA, TIPS-Orkney & TIPS-Islay in 2013

    FES2014 global model under development (CNES project)

    CP4O follow up : proposition for a regional tidal model in the Arctic (with DTU)

    Same methodology can be applied over any continental shelf 02/07/2014 12

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