Tuomo Karvonen

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Microbial processes in soil are moisture, nutrient and temperature dependent and, consequently, accurate calculation of soil temperature is important for modelling nitrogen processes. Microbial activity in soil occurs even at sub-zero temperatures so that, in northern latitudes, a method to calculate soil temperature under snow cover and in frozen soils is(More)
Reasonably simple yet realistic modelling schemes simulating the heat and mass balance within a snow pack are required to provide the necessary boundary conditions for meteorological and hydrological models. An improvement to a one-layer snow energy balance model (UEB, Tarboton et al., 1995) is proposed to better simulate snow surface and snow pack(More)
This thesis summarises development and application of a hydrological model for simulating forest canopy processes, snow accumulation and melt, soil and ground water interactions, and streamflow routing. A motivation behind the model development is to outline a methodology for predicting the influence of land use changes on catchment hydrological processes.(More)
The conceptual and parameter uncertainty of the semi-distributed INCA-N (Integrated Nutrients in Catchments-Nitrogen) model was studied using the GLUE (Generalized Likelihood Uncertainty Estimation) methodology combined with quantitative experimental knowledge, the concept known as 'soft data'. Cumulative inorganic N leaching, annual plant N uptake and(More)
A semi-distributed hydrological model was applied to a small forested catcment in southern Finland. The aim was to demonstrate how differences in terrain properties could be taken into account in modelling runoff generation, and to test how well the presented model simulated streamflow with only limited calibration. Modelling was based on subdivision of a(More)
Many crop models relate the allocation of dry matter between shoots and roots exclusively to the crop development stage. Such models may not take into account the effects of changes in environment on allocation, unless the allocation parameters are altered. In this paper a crop model with a dynamic allocation parameter for dry matter between shoots and(More)
Forest management practices such as clearcutting, site preparation, ditching, and ditch network maintenance increase nitrogen (N) load to streams. In environmentally sustainable forestry, water protection actions are required to decrease the nutrient loading. These include e.g. use of uncut buffer zones between a clear-cut area and a waterbody,(More)