CR 33:195-206 (2007)  -  doi:10.3354/cr033195

ABSTRACT: Changes in the spatial and temporal features of precipitation patterns may have important effects on the magnitude and timing of erosive rainfalls, which will in turn result in changes in soil degradation response. This study presents a secular timescale environmental hazard assessment to account for the impacts of climate erosive forcing on an agricultural landscape identified as potentially vulnerable, mainly to erosional soil degradation processes. An empirical probabilistic model for temporal characterisation of this impact, termed CHIEF (Climate Hazard Index Erosive Forcing), was developed to evaluate the annual balance between climate driving and climate resisting forces in the Po River Basin (northern Italy) during the period 1775 to 2003. In the CHIEF approach, an ecological system adapted to the natural hydro-climatic regime was assumed; fluctuations in this regime, especially those exceeding thresholds of rainfall energy intensity, may trigger erosional soil degradation processes. In this way, the time sensitivity of the CHIEF model reflects the magnitude of annual input nested within patterns of long-term environmental change occurring within a specific temporal window, in order to capture different modes of climatic variability and their hydro-geomorphological implications.

KEY WORDS: Rainfall · Climate erosive forcing · Net erosion · Climate change · Po River Basin · Northern Italy