Projecting Future Extreme Precipitation Pattern in Ohio

Global warming has the potential to intensify hydrological cycle, hence causing more frequent extreme precipitation events. This study aims to project future changes in precipitation pattern in Ohio. We first compared the daily precipitation data output from 20th century runs of various climate models with the historical observations from climate stations within Ohio to evaluate the accuracy of the models and identify the biases. We then apply the bias correction to the 21st century runs of climate models for daily precipitation to make projections on future precipitation patterns for Ohio. In order to examine the spatial variation, we use spatial disaggregation techniques to statistically downscale climate model output. We apply the techniques to both global (GCM) and regional climate model (RCM) output and compare the results to observed values in order to assess the validity of the downscaling method and the performance of climate models. Initial results suggest that the bias correction and spatial disaggregation method, when applied to RCM output, is most successful in reproducing the main features of the observed hydrometeorology from the retrospective climate simulations. By applying this method to future simulations, we find that (a) Annual precipitation is going to increase for Ohio; such increase will be more in northeast and less in southwest; (2) Seasonally, total precipitation will increase most in summer and will decrease slightly in winter; (3) Number of wet days will increase for northeast but decrease for southwest; (4) Number of days with extreme precipitation will increase dramatically for all Ohio.