Land Ice Sea Surface model: Short description and verification

Abstract

Land Ice Sea Surface model (LISS) is a new model for prediction of soil temperature and soil moisture. It is a part of the Non-hydrostatic Multi-scale Model on B-grid (NMM-B). The skin temperature, that represents the temperature of the interface between ground and air, is calculated from surface energy balance. It includes total influence of the soil processes and vegetation cover. Evapotranspiration is parameterized with β parameter that takes into account evaporation from the bare soil, evaporation from interception reservoir and transpiration of the plants. Model has four layers and one or more layers for snow, depending on its amount. Soil temperatures are calculated using Fourier diffusion law and water content using Darcy law. LISS has been tested using two different data sets (Caumont, France 1986; Bondville, USA 1998) as well as against NOAH-LSM simulations. Annual balance of energy and water showed numerical stability. The annual diurnal variation of surface temperature is close to the observed value. RMSE for the surface temperature is 1.9°C for Bonville site. Surface fluxes in 36-hour period of snow growth simulations for Bondville are close to the observed values.