Assimilation of satellite data in a Suspended Particulate Matter transport model

Abstract

The GKSS-BSH three-dimensional suspended particulate matter (SPM) transport module was combined with the hydrodynamic circulation model HAMSOM to simulate 2 years of SPM distributions in the North Sea with fine spatial resolution (3 km horizontally and 21 vertical layers). In addition, the model was forced by wave fields computed with a WAM model set-up on the same grid. The SPM model calculates distributions of three SPM fractions with different settling velocities in the water column and the corresponding fine sediment fractions in the upper 20 cm of the bottom. The local shear stress velocities, derived from currents and waves control the processes of sedimentation, re-suspension and erosion. Waves, currents and the different sinking velocities of the three sediment fractions govern the vertical exchange. In a first step, the results were compared to ENVISAT MERIS satellite data and to in-situ measurements, and a quality control system for the satellite data was developed. In a second step, the satellite data were assimilated into the model using a sequential optimum interpolation scheme. Our focus is to develop a tool for SPM calculations based on modelling and data assimilation, which can be used for operational purpose. Results of the SPM simulations with and without assimilation will be presented and compared with independent observations.