Detail Abstract

Effects of Inhomogeneous Wind and Topography on Surface Mass Transport in a Shallow Lake

Abstract

Wind-induced surface mass transport was investigated under spatially inhomogeneous wind field and different bathymetry gradients in a hypothetical round shape lake. The simple lake was created on top of Lake Kasumigaura to disregard the effect of the shape providing a very first look at horizontal circulation driving changes in surface mass transport. The study utilized the Weather Research and Forecasting model coupled with the Large Eddy Simulation (WRF-LES) to recreate the spatial variation of wind over the shallow Lake Kasumigaura, Japan. Furthermore, this study carried out an integrated method of quantification to identify inhomogeneity levels of the spatial wind field based on a 2D mean filter coupled with the coefficient of variance . After that, each classified snapshot of the wind field was applied to the hypothetical lake with different bathymetry gradients using the hydrodynamic model Fantom-Refined 3D to numerically track floating particles. Based on the numerical results obtained, the effects of inhomogeneous wind field were noticeable under flat topography with strong wind. Interestingly, sloping boundary tended to accumulate the particles in the leeward direction, so that the difference between uniform and non-uniform wind cases was minor.