There is a considerable worldwide resource commitment aimed at improving the ability to accurately simulate the current global climate and to predict future climates. However, the global models do not possess sufficient horizontal resolution to define the regional and local aspects of the climate change. Unfortunately, such regional variations in the climate–system response to global–scale changes can be large, and knowledge of the regional variation is critical in formulating a targeted human response. The method most often used to obtain regional climate change information is to embed higher resolution models of the atmosphere within the coarse–resolution global simulation or forecast models. Technical areas that must be included in such an effort include the modeling of 1) regional (mesoscale) atmospheric processes, 2) the surface–hydrologic system and its interaction with the atmosphere and biosphere, and 3) natural and agricultural vegetation and its response to atmospheric and surface hydrologic processes.

In order to enhance the ability of the world–wide atmospheric–sciences community to address regional–climate–change questions, RAL in collaboration with NESL (NCAR Earth System Laboratory)/MMM is encouraging NCAR to develop a community regional–climate modeling system, most likely WRF–based. Progress in regional climate research and applications could be facilitated if NCAR maintained a standard version of the model, with improvements made and bugs fixed based on the collective experience of the user community. In order to provide community support in this area, NCAR will work toward creating a formal organization of a small core group of scientists with experience in the relevant areas, such as mesoscale modeling, land–surface modeling, and biological–system modeling.

Scientific Questions

There are numerous pressing scientific questions that can be answered with a well-tested, well-maintained and community-accepted regional climate modeling system. These include the following.

• Impacts of regional changes in landscape properties, for example associated with urbanization and deforestation, on regional weather.
• The dynamics of the coupled regional responses of atmospheric, surface-hydrologic and biological processes to large-scale forcing, such as associated with ENSO.
• The coupled regional response of the atmospheric, surface-hydrologic and biological systems to various large scale climate change scenarios, for example associated with CO2 doubling.

Long-term Goals

• Develop a community team that will be recognized as a world-wide scientific leader in regional climate modeling, based on its research experience.
• Develop a community regional-climate modeling system that becomes as well accepted as the community mesoscale modeling system and the CCSM.

Contact: Dr. Tom Warner