Research Projects - Climate Change (Track 1)

Climate Modeling

2009 Annual Report Highlights

Title: Regional and Sub-regional Climate Downscaling for Climate Change Impact over Nevada.

Authors: Dr. John Mejia; Dr. Darko Koracin; and Benjamin Hatchett (Desert Research Institute).

Climate modeling efforts for climate change impact assessment over the SW U.S (with emphasis over the state of Nevada) focus on developing and implementing different approaches to downscale GCMs to grid sizes appropriate (e.g., preferably <10km) for hydrological, ecological, and economic impact modeling studies and predictions. Dynamical and statistical downscaling should produce significant and more reliable climate signals when processes are strongly associated with topographic forcing and other surface boundary conditions upon prescribed large-scale forcing obtained from different climate change future scenarios. However, obtaining reliable estimates of the significance and uncertainty associated with downscaling present and future climate projections are persistent modeling challenges. Interpreting and understanding the inherent weaknesses of the GMCs and those added by the downscaling techniques are part of our current efforts.

Mean surface temperature for Oct-Nov 1975, forced with NCEP/NCAR reanalysis data (2.5° ~ 260 km grid size) and dynamically downscaled using a Regional Climate model for 36, 12, and 4 km grid sizes. Information is gained by incorporating the underlying improved boundary conditions, such as the topography. Note, not necessarily more accurate, but how much more meaningful and richer spatial structures start standing out as we decrease the grid size.

Click photo to enlarge

This work was supported by NSF Cooperative Agreement EPS-‐0814372 to the Nevada System of Higher Education.