Contributions to the SWOT coastal & estuaries white paper SWOT SWOT, Science Definition Team meeting,

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  • SWOT

    SWOT mission Surface Water and Ocean Topography

    Contributions to the SWOT

    coastal & estuaries white paper

    1) Summary of Issues of coastal areas & estuaries, & the SWOT interest & contribution 2) Some results & some answers to the questions of the SWOT use in the macrotidal coasts & estuaries 3) Simulated HR Data in the San Francisco Bay/Estuary Case 4) Recommendations

    B. Laignel, Y. Chao, T. Strub, P. De Mey, F. Lyard, I. Turki

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

  • SWOT

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

    Coastal zones = very complex areas with diverse environments rocky shores with cliffs, beaches with sand, gravel or pebble, estuaries, coastal marshes, wetlands, dunes

    with a difficult balance between economic and ecological issues

    Strong human impact : Population density, harbour, industrial and tourism activities

    è strong urbanization, many building infrastructures, pollutions (human activities) Climate change :

    sea level rise, increase of extreme events in some regions (floods, storm surges)

    3 main issues Inundations : sea level rise & increase of storm surges & floods

    Coastal & estuarine morphological evolution : shoreline retreat, inundation of the wetlands… Water quality change : change of estuary zonation (salinity, turbidity zonation…),

    change of turbidity plume affecting the coastal zone, change of interactions beetwen the hydrodynamics & pollutants

    Issues in the coasts & estuaries

  • SWOT

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

    To answer of these issues : to know perfectly hydrodynamics of these environments

    & its temporal & spatial variabilities

    But these environments are affected by large variations of water level, in connection with many factors & phenomena,

    tide, wave, storm surge, sea level rise, streamflow and groundwater

    Currently The combined effects of these factors & phenomena

    on the spatial & temporal variation of water levels & their impacts on inundations & coastal morphological evolution

    are not well known & therefore difficult modeled

    Hydrodynamics in the coasts & estuaries is complex

    Map of water level in Seine estuary by modeling (T-UGOm) Strong variation of WL Spring tide & Low tide Max variation can reach 8 m PhD L. Chevalier, 2014

  • SWOT

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

    ✔ Most coasts & estuaries do not have enough gauging station to understand the variability of water level & the gauges are sparse ✔ In the coastal zone, the gauges are located in sheltered areas (harbour) & do not allow to precisely study the extreme events that are the phenomena with the most serious consequences in the shoreline

    Main cause of difficulties to the study the variability of the hydrodynamics : low number of gauges

    French network of tidal gauges (REFMAR) 63 tidal gauges For 3427 km of french coasts

  • SWOT

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

    The spatial variability is only studied by modeling, But : - Models are calibrated/validated with few gauging stations or not, - Models require accurate bathymetry data, sometimes difficult to obtain or not existing

    - Models used are more or less adapted to the coast & estuary : Hydrological models simulate moderately or not the marine phenomena (tide, wave, storm surges, sea level rise) Oceanographic models simulate moderately or not the discharge and not the water inputs from groundwater To improve the modelling, we need : -  the scientific communities of oceanographs & hydrologists working together, -  more data of the water level & bathymetry : in situ & satellite data…

    Causes of difficulties to model the hydrodynamics

  • SWOT

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

    to provide information on the spatial variability in different energy conditions, which is curently, mainly & indirectly obtained by modeling But ✔ the previous altimeter missions (TOPEX/Jason) have an inter-track spacing which limited their ability to map smaller-scale features (shelf tides, coastal tides, effect of storm surges in the water level…) (B.K. Arbic et al., Tides/SWOT white paper) ✔ In the estuaries,

    - the contribution of satellites mainly concerns the monotoring of water color & relation to the suspended sediment - there are few studies of hydrological variability from altimetry

    Contribution of satellites to study the hydrodynamics in the coastal zones

  • SWOT

    To provide a spatial information on the water levels with high spatial resolution (maybe 250 m in the coastal zones and 100 m in estuaries)

    In different hydrodynamic conditions : Combination of neap/spring tide, high/low tide, storm surges or not,

    high/low flow

    - at the regional scale, in key sectors (with economic and/or ecological interest and/or potential hazard…) : wetlands, islands, estuary mouth, floodplains, zones with shoreline retreat…

    - at the global scale, from the comparison of regional panel

    In order : to better understand & modelling the hydro-meteo-marin phenomena

    & their impact on the spatial water level & on the evolution of the coastal & estuairies systems at the regional & global scale

    SWOT contributions

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

  • SWOT SWOT

    contributions Water level maps obtained by modeling in the

    Normandy coast & Seine estuary, The water levels are spatialy, highly variable in - different hydrodynamic conditions - specific hydrodynamic condition This high spatial variabilty of water level can be observed for distance less than 1 km Only SWOT has sufficient spatial resolution to study & better understand & model this spatial variation in different hydrodynamic conditions

    Seine estuary PhD L. Chevalier, 2014

    Neap tide

    Spring tide

    H ig

    h tid

    e H

    ig h

    tid e

    Lo w

    ti de

    Lo

    w ti

    de

    Normandy coast

  • SWOT

    The monitoring & mapping of water levels & morphological changes associated is an essential support for the implementation of strategies for navigation, economic development & security of property and people (inundations, coastal retreat…)

    ✔ Identification, survey & mapping of seasonal & interannual variability of water level & inundations (flood & storm surge), including support for modeling the propagation of inundations (providing elements for understanding the limits of inundations extension) ✔ Understanding of the interactions between different water bodies & their impact on the water level & changes in the estuary zonation related to the sea level rise ✔ Survey & mapping of the islands & channels changes ✔ survey & mapping of the seasonal & interannual changes of water areas in the wetlands (natural and artificial lakes) for a best managment of water level for several using (agriculture, nature reserves, leisure centers…) ✔ Ecological conservation & restoration: evolution of fauna & flora & their habitats in relation to the water level… ✔ survey of the water quality in relation to the hydrodynamic conditions, for :

    survey of evolution of the salinity gradient and high turbidity zone prevention of low water thresholds leading to the decrease of oxygen in estuaries prevention of flood thresholds leadind to the turbidity plumes into the sea

    ✔ survey of the water level in the main big harbours

    Many applications of SWOT in coastal zones

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

  • SWOT

    ✔ How to establish the continuum from regional ocean – coasts – nearshore – estuaries – rivers ? ✔ What is the offshore limit of SWOT HR simulations required for coasts - nearshore - estuaries ? ✔ How do we develop discharge algos at river mouths ? ✔ What ocean & wave models are available in coastal/littoral for testing 100 m / 250 m resolution processes? Which scenes & preliminary SWOT analyses should be provided by the project in coasts, estuaries, open ocean at 100 / 250m resolution ? ✔ What are the most appropriate models in estuaries ? ✔ About the SWOT simulator HR, what are the needs for coastal areas & estuaries ? ✔ What is the SWOT sensitivity to record the tide in coastal zones ? ✔ Can SWOT capture the storm surges which are the main phenomena of change in coastal areas (with inundation & coastal retreat) & the floods in estuaries ?

    Some questions for using SWOT in the coasts and estuaries…

    SWOT, Science Definition Team meeting, San Diego 13-15, January , 2015

  • SWOT

    SWOT mission Surface Water and Ocean Topography

    Some results & some answers to the questions of the SWOT u