Effect of Climate Change on Forest Soil Hydrology - Case Study Achenkirch

2003

S. 60

Artikel aus einem Buch

200107821

We compared the recently measured and the simulated soil water content, the rate of water runoff at the soil surface and the percolation rate below the rooting zone for a montane Norway spruce (Picea abies) forest soil in Achenkirch, Tyrol. The site Achenkirch was already subject to long-term biogeochemical measurements and a thorough assessment of the nitrogen dynamics. Our objective was the predicition of soil hydrology in a changed climate in order to eventually predict the nitrogen cycle under future warmer conditions. The IPCC scenario of a doubled partial pressure of atmospheric CO2 predicts a global rise in temperature of approx 2°C. A two-step modelling approach was taken: (i) The large scale simulations of the global climate model ECHAM4 were amended with regionally vaild features and constraints in order to provide a climate predictions for Southern Bavaria and Northern Tyrol. (ii) The derived climate data were used as input data for the forest hydrology model Brook-90 and the soil hydrology model Hydrus-2D. The climate model yielded little changes in winter temperatures, but a warming of summer air temperatures of up to 5°C within 50 years. The simulated precipation considerably biased. We therefore calculated the relative regional climate change from the consistently biased simulations of the present and future climate and superimposed the time series of measured climate data with the derived indexes of climate change. Rain is frequent in Achenkirch and soils are consequently always moist.