Mesoskalige Modellierung der Bodenhydrologie

Abstract

This paper presents the modeling of soil hydrology within a soil-vegetation model. Until now the components of soil hydrologic cycle were only roughly taken into consideration in mesoscale models. Due to a very large influence of the soil moisture on the development of the lower atmosphere, some important hydrological processes are included here into the soil-vegetation model of the 'Karlsruher Atmospharisches Mesoskaliges Modell' (KAMM2; Karlsruhe atmospheric mesoscale model): parameterizations of water storage at the earth surface, runoff and macropore flow. The boundary conditions of the soil model were altered to obtain a realistic infiltration of precipitation and the simulation of ground water. Further different parameterizations of soil hydrologic parameters and a soil texture classification were included. For each parameter of soil and vegetation a season dependent dataset was obtained. For the validation of this extended model, simulations were ran and compared to measured values. Sensitivity studies show that the choice of soil texture and soil texture classification and to a smaller extent also the initial value of soil moisture have a large influence on the lower atmosphere. Important processes are further the ponding of water at the earth surface and macropore flow, while ground water can be ignored. The best results for parameterization of soil water transport are obtained utilizing hydrology approaches that were not yet applied in meteorology.