Study of Climate Change Impact on Hydrological Systems using Downscaling Tools

Climate change impact on hydrological systems has received wide attentions over the past decades. In this study, a coupled downscaling and hydrological modeling study was conducted. Statistical downscaling models are used for building the linkages between the atmosphere variables of general circulation model (i.e. CGCM3) and local weather records. The involved variables related to hydrologyinclude precipitation, temperature, radiation, wind speed and relative humidity. The output from downscaling wasused for coupling with the Soil and Water Assessment Tool (SWAT) to assess the hydrologic variability at the Heshui watershed, Jiangxi province, China. A highlight of this study wasthat the observed historical meteorological datacouldbe based on high resolution grid data, includingClimate Forecast System Reanalysis (CFSR) and APHRODITE's Water Resources. The monthly average stream flow and extreme record at historical and future periods wereexamined and compared. The results indicatedthat the downscaling tools could effectively help obtain high-resolution climate or climate change informationfrom relatively coarse-resolution climate models. This study alsoprovidedavaluableguideline for assessing water resourcesavailabilityunder climate change at the regionsthat containlimited meteorological data.