Author(s): Hein Hartmut; Stephan Mai; Ulrich Barjenbruch
Keywords: No Keywords
Abstract: In coastal regions the estimation of most accurate drying periods of tidal flats is important for heat flux processes. In relation with climate change impact on coastal regions, the rising sea level and increased tidal amplitudes result in shorter drying periods of tidal flats. Due to the different albedo of seawater and tidal flats the heat balance changes. Moreover, heat budget in coastal wetlands is important for the health of the ecosystems. Our study investigates into the uncertainty of drying periods, due to an uncertain representation of the topography in coarse coastal climate impact models. Therefore we use an example region: the east Frisian Wadden sea between the island Borkum and the German coastline. To simulate likely future states of drying periods we use a so called “model-chain” , which is the synonym for the regionalization or downscaling of global climate scenarios toward the regional coast. Our results show the importance of the numerical algorithm (e. g. first-order or high-order). Dependence of the grid-size of simulations is crucial to the drying period. With higher resolution of the topography, individual tidal creeks are better represented. In general, we conclude that the coarser the grid-size, the shorter the drying periods. With the indicated rising sea non-linear aspects play a significant role. One must conclude that inhomogeneous grid-sizes result in inaccurate estimations of changes in coastal heat budgets and may cause false interpretation of future health changes of the coastal ecosystem.