Potential changes in rainfall erosivity under GCM climate change scenarios for the southern Appalachian region, USA

Abstract

The potential change in rainfall erosivity, the R-factor in the RUSLE model was investigated under three future climate change scenarios A1FI, A1B and B1 in the New River basin of East Tennessee. Data from Community Climate System Model (CCSM) global circulation model (GCM) was used for spatial–temporal statistical downscaling to the study site. R-factors for future dates were estimated by spatial downscaling of monthly precipitation data obtained from CCSM model and then temporally downscaled to produce daily weather series by means of the CLIGEN stochastic weather generator. CLIGEN was calibrated by the historic rainfall data for the period 1959 to 2000, and used to model future rainfall amounts and associated statistics for 2010–2099. Erosivity R-factors for the historical dataset was estimated as 4085MJmmh−1ha−1 and increased between 7% and 49% for future GCM scenarios estimated as 4525.5, 5376.2, and 6281.3MJmmh−1ha−1 per B1, A1B, and A1FI scenarios, respectively. Results showed that for all three GCM scenarios increased rainfall erosivities had similar monthly distributions. Projected erosivities suggest that by about 2099 the annual rainfall erosivity in the study region will be about the same as what is currently experienced in northern to central Alabama. The same statistical downscaling technique applied in this study is applicable to other world regions. This study provides necessary information to assess potential changes in sediment yields in the southern Appalachian region from various land use activities impacting soil cover. Particularly important to this region where coal mining activities are common, is estimating the potential in change in sediment yields from this land disturbance, and plan for improved erosion control practices.