Regional climate simulations have to take place in the context of global climate simulations. Several modeling framework may be used to accomplish this. In this research we pursue an ultra high-resolution climate modeling framework suitable for studies of regional climate change by interactively nesting a meso-scale model in a global climate model. This differs from the typical dynamical downscaling approach in that the mesoscale model is a part of the global model: information within the regional scale model will feed back to the large-scale model. We specifically propose to develop a model through two-way nesting of the WRF and CCSM. The nesting will be between the WRF and CAM, the atmospheric component model of the CCSM. The integrated model aims to be able to more accurately resolve and simulate severe weather events of regional climate importance at ultra-high resolutions, and meanwhile carry out long-term climate simulations to project future climate change. The model will be flexible enough to be configured for specific regions of interest. The specific objectives of this project are to:

1. Develop a mathematical framework of two-way interactions of the WRF and CCSM that will meet conservation and numerical stability requirements of the coupled system as a single climate model.
2. Implement the two-way nesting using parallel model coupling approach that scales on massively parallel computers.
3. Develop a suite of experiments, using the standalone WRF and CAM, and coupled WRF and CAM, to verify and evaluate the implementation of the model.
4. Demonstrate the utility of the model for regional climate change simulations.
5. Deliver an integrated CCSM-WRF climate model to the community.