Previous 21ST century climate projection datasets from coupled model intercomparison projects(cmip) such as cmip phase 3 and cmip phase 5 (CMIP3 and CMIP5, respectively) have been used for producing…

Previous 21ST century climate projection datasets from coupled model intercomparison projects(cmip) such as cmip phase 3 and cmip phase 5 (CMIP3 and CMIP5, respectively) have been used for producing high resolution gridded (12-KM or 6-KM) hydrologic projections over thecontiguous united states (CONUS) via a modeling chain consisting of applying downscaling methods and hydrologic models after selection of a number of cmip simulations. Such productshave been applied for water resources applications at both regional and watershed scales. Usesinclude ecological assessments, water management applications, and risk management decision making.while high-resolution hydrologic modeling is important to resolve local variations of energy andmoisture fluxes over heterogeneous topography vegetation and soil, computational constraintsrestrict century-long simulations forced by large ensembles of climate forcings. Recent advancesby ncar are leveraging the concept of catchment based spatial discretization. This improves hydrologic model performance by making model components more landscape aware. This allows for fewer overall spatial elements than traditional, grid-based models. Catchment-basedriver routing models more accurately depict river reaches and catchments than grid-based routing models. This supports streamflow estimates at geographically accurate river locations of interest. Now that cmip phase 6 (CMIP6) climate model and CONUS focused statistically downscaled data are available, we propose a project that will incorporate the new, CONUS-wide climate information and our new hydrologic modeling approach to update the existing 21ST century hydrologic (streamflow) projection datasets publicly available for download on the green dataoasis (GDO) website over the CONUS and across transboundary basins. The provision ofreliable, consistently generated information, representing state of the art earth system model (ESM) output is a critical need for federal, state, and local agencies.