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

Modelled processes Z1 = 0,…,1mm Z2 = Z1,…,10cm Z3 = hero,…,10cm Z4 = 10cm hero = 0,…,10cm transport vertical exchange transport resuspension erosion sedimentation Bioturbation, diffusion sinking 1. currents: 2. waves: Shear Stress velocity sinking sedimentation

1 water column: SPM dynamic ,08m2,11m From Sedimentation to Resuspension Increasing wave height, constant currents

NEA: 24 nm, NS: 6 nm, BS: 1nm Model domains and nesting no SPM SPM const. bv

SPM-configuration at the sea bottom

Global, medium range: ECMWF Regional, short range: Hirlam 4x/day Weather models

x ,2 x 2 Wave model: WAM cycl. 4, Kitaigoroskii scaling 4x/day 60h

River Inflow Firth of Forth Humber Wash Scheldt Rhein Weser Elbe q < 10 mg/l q > 10 mg/l Scheldt 100 mg/l Wash 60 mg/l Humber 55 mg/l Firth of Forth 48 mg/l Elbe 38 mg/l Weser 35 mg/l Rhein 30 mg/l 79 rivers

Cliffs Suffolk 50 kg/s Norfolk 45 kg/s Holderness 58 kg/s Suffolk Norfolk Holderness English channel Constant mass Input rate at the Specified grid points in the English Channel (North Sea boundary) and at the Cliffs (Suffolk, Norfolk, Holderness)

First results: runtime 23 days longer forerun needed

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