New Daily and Monthly Downscaled CMIP5 Climate Projections

This presentation highlights an effort to apply two statistical downscaling techniques -- monthly bias-correction and spatial disaggregation (BCSD) and daily bias-correction and constructed analogs (BCCA) -- to a large ensemble of new climate projections released through the World Climate Research Programme (WCRP) Coupled Model Intercomparison Project phase 5 (CMIP5). The downscaled projections have been developed over the contiguous U.S. and represent the latest content addition to the "Bias Corrected and Downscaled WCRP CMIP3/5 Climate and Hydrology Projections" web archive, available at: http://gdo-dcp.ucllnl.org/downscaled_cmip_projections/.

Archive efforts stem from recognition that water managers need to assess what future climate change could mean for the management of their systems, and to assess when vulnerabilities and impacts would appear to cross thresholds triggering need for adaptive intervention. In order to assess such needs, managers must be able to quickly and easily access global climate projection information that has been bias-corrected to account for systematic climate model errors and downscaled to reflect local controls on climate.

Reclamation began addressing this need in 2007, collaborating with Santa Clara University and Lawrence Livermore National Laboratory to apply the monthly BCSD technique to 112 monthly global climate projections over the continental U.S. Since making that dataset and web-service publically available in November 2007, more than 1000 users in the U.S. and abroad have submitted 11000 download requests, using this information to support a variety of research, planning and education activities. Building on the success of that effort, the collaboration expanded to include Scripps Institution of Oceanography, U.S. Geological Survey, Climate Central and the U.S. Army Corps of Engineers in applying the daily BCCA technique to a 53-member subset of the 112 original projections, thereby producing downscaled information on daily temperature range and precipitation patterns, which are respectively relevant to ecological and flood risk studies. Reclamation has also collaborated with University of Washington and the National Weather Service Colorado Basin River Forecast Center to develop hydrologic projections over the Western U.S. corresponding to the 112 monthly climate projections. For more information on this resource, see the web site listed above.

The presentation will focus on the new CMIP5 content addition, data access, tutorials, and application examples using the original CMIP3 content. The new CMIP5 content has been developed at the same spatial and temporal specifications as the archive's downscaled CMIP3 content, thereby permitting easy comparison between the two WCRP sets of information. CMIP5 content will include >80 historical climate simulations setting up >200 future projections representing four representative concentration pathways (2.6, 4.5, 6.0 and 8.5). The presentation will also discuss other downscaled climate and hydrologic projection products that are being evaluated or in development by archive collaborators.