Research Needs and Directions of Regional Climate Modeling Using WRF and CCSM
Climate varies across a wide range of temporal and spatial scales. Yet, climate modeling has long been approached using global models that can resolve only the broader scales of atmospheric processes and their interactions with land, ocean, and sea ice. Clearly, large-scale climate determines the environment for mesoscale and microscale processes that govern the weather and local climate, but, likewise, processes that occur at the regional scale may have significant impacts on the large scale circulation. Resolving such scale interactions will lead to much improved understanding of how climate both influences, and is influenced by, human activities. Since October 2003, the National Center for Atmospheric Research (NCAR) has supported an effort through the Opportunity Fund to develop regional climate modeling capability using the Weather Research and Forecasting (WRF) model (http://www.wrf-model.org/index.php) and the Community Climate System Model (CCSM) (http://www.ccsm.ucar.edu/models), with participations by members of both the Mesoscale and Microscale Meteorology and Climate and Global Dynamics Divisions. The goal is to develop a next generation community Regional Climate Model (RCM) that can address both downscaling and upscaling issues in climate modeling. Downscaling is the process of deriving regional climate information based on large-scale climate conditions. Both dynamical and statistical downscaling methods have been used to produce regional climate change scenarios; however, their resolution and physical fidelity are considered inadequate. Hence, the global change community has expressed a strong demand for improved regional climate information to explore the implications of adaptation and mitigation and assess climate change impacts (http://www.climatescience.gov/events/workshop2002/). Upscaling encapsulates the aggregate effects of small-scale physical and dynamical processes on the large-scale climate. One form of upscaling is the use of physical parameterizations such as that for deep convection. These are also considered to be inadequate, as much of the uncertainty in model sensitivity to greenhouse gases is now known to be associated with cloud parameterizations. Another form of upscaling is to explicitly include the effects of regional processes on the large-scale environment, both locally and remotely. Since their inception in the late 1980s, RCMs have been used predominantly to address downscaling issues through one-way coupling with global analyses or climate models. As part of the NCAR project, WRF has been adapted for simulating regional climate. Seasonal simulations over the U.S. have shown realistic features including the low-level jet and diurnal cycle of rainfall in the Central U.S. (Leung et al. 2005), and orographic precipitation in the western U.S. (Done et al. 2005). A WRF Regional Climate Modeling Working Group has been established to coordinate RCM research activities. To help define the next steps, a workshop on “Research Needs and Directions of Regional Climate Modeling Using WRF and CCSM” was organized to engage the regional and global climate modeling communities to: (1) define research needs for the development of a next generation community RCM based on WRF and CCSM; (2) define upscaling and downscaling research that can be addressed by RCMs; and (3) develop a plan of actions that would meet the research needs. This article summarizes the research issues and recommendations discussed at the workshop. There is no implied order in the research priorities listed below. Workshop agenda and presentations can be found at http://box.mmm.ucar.edu/events/rcm05/.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 898630
- Report Number(s):
- PNNL-SA-46312; TRN: US200706%%240
- Journal Information:
- Bulletin of the American Meteorological Society, 87(12):1747-1751, Journal Name: Bulletin of the American Meteorological Society, 87(12):1747-1751
- Country of Publication:
- United States
- Language:
- English
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