Climate change and soil moisture: a case study

An important aspect of regional climate change is alteration in soil moistu re availability. The EPIC (Erosion Productivity Impact Calculator - Sharple y and Williams, 1990) model is applied to estimate soil hydrology consequen ces in a representative subcatchment (24 km(2)) of Lake Balaton, Hungary. T he study is based on the soil hydrology parameters of the EPIC model, which exhibit a relatively fast response to the climate variations. To specify t he regional climate scenario for Hungary in semi-annual time resolution, a statistical approach computing regression between regional and hemispherica l mean climate characteristics is employed. The semi-annual scenarios are f urther refined by applying the principle of geographical analogy. This diff erence corresponds to a 0.5 degrees K increase of the hemispherical mean te mperature, i.e. the climate after 20-40 years of monotonous warming (IPCC, 1996a). Diurnal statistical parameters which correspond to present (base-li ne) and future climates of the investigated site are finally introduced int o the built-in weather generator of the EPIC model. A supplementary factor of variation in soil hydrology is crop-rotation, responsible for half of th e standard deviations, as compared to the hypothetical maize monoculture ex periment. Climate generated differences in transpiration, soil moisture con tent, and crop-available water during water stress days. In connection with the assumed warming, there is a general trend towards drought during the v egetation growing period. (C) 1999 Elsevier Science Ltd. All rights reserve d.