The Contribution of High Resolution Medium Range Weather Forecast to the Improvement of Hydro-Climate Prediction

The hydro-climate prediction driven by the short-range climate forecast, focus on the soil moisture (SM) and surface runoff, are still unskillful after one or two months leading time, based on the current operational Climate Forecast System (CFS) version 2. In this study, we explored the potential improvement for the SM and Runoff forecast by merging more skillful high resolution Medium Range Forecast (MRF). The evaluation shows the MRF has better forecast skill over the CFSv2 ensemble forecast, in particular during the second week. Although the difference in the Pearson correlation for precipitation is most insignificant at statistics testing, the MRF show strong skill at temperature over the CFS. As a result, combining MRF and CFS forecast together as the meteorological input for the Variable Infiltration Capacity (VIC) meso-scale hydrological model, it will improve the soil moisture and accumulated runoff forecast. The improvement can persistent to the next few months in some region, due to the soil moisture memory.