Luyten coherens a numerical tool for the management of the marine coastal environment

COHERENSA numerical tool for management of the 

coastal marine environment

Patrick Luyten, Valérie Dulière, Geneviève Lacroix, …RBINS‐OD Nature

ExamplesProtection of beaches and coast lines

Fishery policies

Ports, shipping lanes, coastal industries, tourist areas

Pollutants from rivers and human-induced discharges

Operational forecasts

Climate change

Core(hydrodynamics, numerical/parallel and

other common tools)

user-friendly interface for setupstandard data formats for easy

visualisationinundation

waves biology(microplankton, nutrients)tracers sediment

structures module (dams, groynes, discharges)

Lagrangian Eulerian dredging/relocationsea bed morphologywater column transport

available in progress plannedresidence times

to be merged

model coupler

What does COHERENS contain?

Sea ice

Inundation schemes

Flow over an obstacle

Multiple weirs

Discharge module

Locations are either fixed or moving (e.g. ships)

Vertical position selected by the user:o bottomo surfaceo fixed distance from the bottomo fixed distance from the surface

Homogeneous or directional volume discharge

Discharged variable can be T, S, sediment or contaminant concentration

Overview of the different modulesfor sediments

Bed load module:Algebraic equationSediment transport module

Morphological module

Suspended load: Advection diffusion equationSediment transport module

Dredging dumping module

Morphological module

8

3 22

1

4

Update of bed elevation

Vertical sorting

Avalanching

COHERENS

• Wave parameters from SWAN• Sea bed: enhancement of the bed 

shear stress (important for sediment erosion and bed load)

• Water column: Stokes drift and wave radiation stress (2‐D and 3‐D)

Wave model (SWAN)

• Water depths and currents from COHERENS for wave‐energy equation

y g

Model coupler• Exchange data between 

COHERENS and SWAN using MCT library

• Performs interpolations• Generic to allow coupling with 

other (e.g.meteorological) external models or for 2‐way nesting 

Wave-current interaction and model coupling

User friendly set up

Objectives:

User-friendly setup

Standard data formats

Make COHERENS easier to use for less experienced users

Implementation:

Central Input File (CIF): comprehensive setup of model parameters using (e.g.) short hand switches

Internationally recognized data formats (CF-1.6) for input/output (netCDF) files

COHERENS

Climate studiesCORDEX,

CREST

Operational forecastsOPTOS

BiologyMIRO&CO, CLIMARCO

Sediments Indy67, Tiles Capacity building

CEBioS

Tracersoil spills, fish larvae,

Emosem, Jellyfor, Newstep

Applications at RBINS

Data assimilationJERICO, BCZ

Polar studies (Recto)

Example of application :Identification of potential polluters

Image from CleanSeaNet

Modelled slick

Observed slick

Model results

Release

2012/10/10 6h08

Observed slick

2012/10/10 6h00

Forecast and backtrack of drifting objectsSAR (Search And Rescue)Backtrack beached porpoises

Probable zones of death for beached porpoises (spring 2006 and 2009)

- 6 main spawning grounds in the North Sea,

Superindividuals (107 eggs)3-month period

Spawning grounds: Eastern Channel, Belgian Coast, Texel, German Bight, Norfolk, Thames

-4 -2 0 2 4 6 848.5

50.5

52.5

54.5

56.5

Longitude (°E)

Latit

ude

(°N

)

eggs/m²/d

FRBE

NL

GE

UK

0

1.5

2.5

3.5

6

10

16

NGBTx

BC

EC

Th

Redrawn fromICES, 2005, Bolle et. In prep

Nurseries: France, Belgium, Netherlands, Germany, Norfolk (UK), Thames (UK)

-4 -2 0 2 4 6 848.5

50.5

52.5

54.5

56.5

Longitude (°E)

Latit

ude

(°N

)

FRBE

NL

GE

UK

NoGE

NLBE

FR

Tha

- 6 nurseries: coastal areas (< 20m), high proportion of sand and/or mud (from EMODNET-

GEOLOGY substrate map

Kaskela et al, 2010

-4 -2 0 2 4 6 848.5

50.5

52.5

54.5

56.5

Longitude (°E)

Latit

ude

(°N

)

FR

BE

NL

GE

UK

mud to sandy mud sand to muddy sand coarse-grained sediment mixed sediment bedrock

20 m

Intro Model Results CCL-Perspectives

IBM: spawning grounds & nurseries

-4 -2 0 2 4 6 848.5

50.5

52.5

54.5

56.5

Longitude (°E)

Latit

ude

(°N

)

FRBE

NL

GE

UK

1995-2011

Final dispersal pattern

# larvaeNurseries

No

Tha

Origin

-4 -2 0 2 4 6 848.5

50.5

52.5

54.5

56.5

Longitude (°E)

Latit

ude

(°N

)

eggs/m²/d

FRBE

NL

GE

UK

0

1.5

2.5

3.5

6

10

16

NGB

TxBC

EC

Th

Origin of the larvae

Spawning grounds

-4 -2 0 2 4 6 848.5

50.5

52.5

54.5

56.5

Longitude (°E)

Latit

ude

(°N

)

FRBE

NL

GE

UK

NoGE

NLBE

FR

Tha

Nurseries

Intro Model Results CCL-Perspectives

Forecast model simulation Source : wikipedia

Dispersion related to release moment(hourly release during 24h)

Situation after 4 weeks

India: Mandovi/Zuari estuary

http://odnature.naturalsciences.be/coherens/

COHERENS international user group(1727 registrations)