Coupling of the GKSS Suspended Particular Matter (SPM) model with the

DMI circulation model: BSHcmod

Jens Murawski, Gerhard Gayer

WP6: YEOS Sediment transport model

• The development of a prototype of aYellow-Bohai Sea sediment forecasting system

• Task 6.5: Implementing and testing of the operational configuration of the GKSS-SPM model.

• First steps: Coupling of the GKSS-SPM model with the DMI circulation Model BSHcmod. Tests of the SPM-BSHcmod in the North Sea and Baltic Sea.

Whats done?

• Rewriting of the f77-SPM-subroutines to f90 language: SPM_module.f90.

• Numerical Implementation of the GkSS-SPM model into the DMI circulation model.

• Writing of Preprocessing skripts and tools to download and handle wave data.

• Modification of existing scripts to run the coupled SPM-circulation model, including preprocessing.

• First tests of the coupled SPM-circulation model in the North Sea / Baltic Sea using the operational setup provided by the GKSS.

Motivation, Features• Why? SPM is of particular importance for the eccosystem. It

regulates the penetration depth of light and influences the nutrients concentration in the water column.

• Where? The Suspendet Matter model is the collaborative development of the GkSS research center and the BSH (Gerhard Gayer et al. 2005).

• Processes? The regional circulation model (cmod) was extended by an Suspended Particulate Matter module to include vertical exchange processes (sedimentation, resuspension and erosion), bottom processes (consumption and bioturbation) and the horizontal redistribution of SPM due to currents and waves.

• Features? The new feature of the SPM model is the inclusion of wave effects into the description of the sediment dynamic. The SPM contribution of 79 rivers is included in the model.

• 3 suspended matter fractions: wsink(frac1)=0.0001 m/s

wsink(frac2)=0.00002 m/s wsink(frac3)=0.001 m/s

Modelled processes

zh

smu /01,0

smu /028,0

smu /0099,0

Z1 = 0,…,1mm

Z2 = Z1,…,10cm

Z3 = hero,…,10cm

Z4 = 10cm

hero = 0,…,10cm

transportvertical exchange vertical exchange

transport

resuspension

erosion

sedimentation

Bioturbation, diffusion

sinking

1. currents:

2. waves:

T

hHu Swave

)(~

wavecur uuu ,

UCu Dcur

Shear Stressvelocity

sinking

sedimentation

1 water column: SPM dynamic0.0001950.0003610.0003860.0004100.0004310.0004470.0004590.0004670.0004690.0004660.000458

0.0000460.000093

6.656.65

htt 100

2,08m 2,11m

From Sedimentation

to Resuspension

0.0004470.0004450t

0.0001910.0003650.0003910.0004170.0004400.0004600.0004750.0004850.0004900.0004890.000485

0.00.000098

6.656.65

0.0004780.000477 Increasing wave height,

constant currents

NEA: 24 nm, NS: 6 nm, BS: 1nm

Model domains and nesting

no SPM

SPM

const. bv

const. bv

SPM-configuration at the sea bottom

Global,medium range:

ECMWF

Regional,short range:

Hirlam

4x/day

Weather models

6

1

30

6 x 10

10

1,2 x 2

Wave model: WAM cycl. 4,Kitaigoroskii scaling

4x/day60h

River Inflow

Firth ofForth

Humber

Wash

ScheldtRhein

WeserElbe

q < 10 mg/lq > 10 mg/l

Scheldt 100 mg/lWash 60 mg/lHumber 55 mg/lFirth of Forth 48 mg/lElbe 38 mg/lWeser 35 mg/lRhein 30 mg/l

qTime

Vol

Time

mass

79 rivers

Cliffs

Suffolk 50 kg/sNorfolk 45 kg/sHolderness 58 kg/s

Suffolk

Norfolk

Holderness

English channel

Constant massInput rate at theSpecified gridpoints in theEnglish Channel(North Seaboundary) andat the Cliffs(Suffolk, Norfolk,Holderness)

First results:runtime 23 dayslonger forerunneeded

Next steps• More and longer test runs in the North Sea.

Comparrison of DMI model results with GKSS/BSH results.

• Going to the Yellow sea:

SPM bottom configuration map?

River loadings (annual variability)?

Const. coarse grid boundary values?

• Validation data Yellow-Bohai Sea?

• Data assimilation: Satellite information?

Thank you