Priority 4: Developing Community Models

Developing numerical models and making them available to the scientific community is at the heart of NCAR's research and service to the community. Key activities in this priority are community models, research models, and progress toward an Earth system model. Developing numerical models and making them available to the scientific community is at the heart of NCAR's service to the community. Leading the way in the key activity of community models are the CCSM and the WRF. The CCSM is a coupled model combining representations of the atmosphere, ocean, land, and sea ice. WRF is a next-generation mesoscale numerical weather prediction system designed to serve both operational forecasting and atmospheric research needs. There is strong community participation both in developing the models and in using them. Additionally, NCAR continues to develop and use together with the community to a lesser extent a variety of other research models. This combined model development will contribute to the creation of a comprehensive Earth System Model, a top priority for NCAR and a task that will likely be undertaken in collaboration with the the university community. This system will be developed around the interactions of the Earth's physical, chemical and biogeophysical systems with future inclusion of human and societal elements.

Accomplishments

The key activity of this strategic priority is community modeling. The defining factors of a community model are the wide inclusion of collaborators from the universities and other modeling centers, the accessibility of the models, and the community service provided by NCAR researchers to the outside community. The flagship models of this kind are the CCSM and the WRF. See projects related to this priority. On the following pages, we describe our work CCSM and Intergovernmental Panel on Climate Change (IPCC) that supports this strategic priority.

Another activity within this priority is the development of research models that are in line with community models but at this time lack the far-reaching community support factor. These models are integral parts of NCAR research, and are being developed with and used by both NCAR and university researchers. Much like the community models, simulations are run and the output data is shared and analyzed by NCAR scientists and our collaborators. See projects related to this priority.

The final key activity within this priority is moving toward an Earth System Model. Work in this area includes extending our community models to incorporate chemistry, biogeochemical cycling, and ecosystem; ability to cross scales of motion; and, at some point, incorporating the human factor. The framework should enable component models to function in a fully coupled manner, and employing a hierarchical approach that provides flexibility to select between formulations best suited to particular investigations. See projects related to this priority.On the following pages, we highlight our work and plans for Nested Regional Climate Model in support of this priority.

Program Plans

Community models

The CCSM project will work towards developing a first-generation coupled chemistry-climate model in the next two to three years. A project of this scope will necessarily involve scientific partnerships across NCAR and the external CCSM community. The current long-term plan of the CCSM project is to develop and freeze the next version of the model, CCSM-4, by the end of 2008. In addition to several other improvements, this version will most likely have new components for the carbon cycle and interactive atmospheric chemistry. This will enable a whole new range of scientific questions to be asked of, and answered by, the CCSM. In addition, the CCSM-4 will be the model used to contribute to the next IPCC report.

NCAR will continue to assist both domestic and international users of the WRF/ARW modeling system, and will organize WRF workshops and tutorials to accommodate the expanding use of WRF for both research and operations. Current plans are to convene the 8th WRF Users Workshop in June 2007 and to conduct tutorials in January and July of next year. We plan a major new code release (V2.2) that will allow community access to all of the newly developed model features. We are looking at establishing an external advisory board in order to provide community input on WRF code management and community-support activities.

Research models

Use WACCM to study the effect of the middle atmosphere on the tropospheric climate. NCAR scientists and collaborators will be looking at the potential impact that the middle atmosphere has on tropospheric climate sensitivity.

Extend WACCM to the top of the thermosphere and to implement the main thermospheric and ionospheric processes in the model. The plan is to develop a WACCM model that can reproduce the thermospheric thermal and compositional structures and €the diurnal variability, with an empirical,€ interacting ionosphere.

NCAR will continue to host the International Project Office for the International Geosphere-Biosphere Programme's (IGBP) Earth System modeling project: Analysis, Integration and Modeling of the Earth System (AIMES). The AIMES project extends Earth System modeling approaches to include human processes. Modeling activities in AIMES will continue to test the sensitivity of tradeoffs in vulnerability and resilience in terms of economic and ecosystem consequences.

Continue evaluation of MOZART-4 through comparisons with satellite and in situ measurements as well as additional testing of the impact of analyzed meteorological fields on chemical simulations.

Continue to analyze the incorporation of interactive chemistry in the CAM. For extended chemistry-climate studies, a number of different options exist for simulating aerosols and chemistry to facilitate using the model in the optimal configuration. For example, aerosols can either be prescribed, simulated using simple input oxidant fields, or simulated with a model. We plan to evaluate the model performance under different options.

Toward an Earth system model

The near-term goals of the NRCM project are to improve our understanding and ability to simulate the complex, multi-scale interactions intrinsic to atmospheric and oceanic fluid motions. The accurate representation of these scale interactions is critical to both climate projections and weather predictions, and they are likely key to resolving some of the longest standing biases in climate model simulations. Future plans for the nested regional climate modeling include analyzing the initial data, continuing experiments using the NASA Columbia computer for another six years of climate simulations (2000 - 2005), taking the next critical step of embedding ARW into CAM to undertake both current and future climate simulations. Future work in support of intraseasonal tropical climate variability research includes quantifying the role of convective organization in the MJO. Other plans include extending current climate and tropical cyclone research, and utilizing the new NCAR NRCM to examine the environmental changes associated with observed trends and variations of tropical cyclones. The NRCM will be coupled into the NCAR CAM to enable projections of future trends in tropical-cyclone characteristics.

Continue to improve predicting intra-seasonal tropical climate variability. Future plans are to quantify the role of convective organization in the MJO by dynamical and numerical modeling, by designing new mesoscale parameterizations for climate models, by multi-scale simulations of natural precipitating systems observed by Tropical Rainfall Measuring Mission (TRMM)/CloudSat, and by analysis of multi-scale convective organization in the aforementioned tropical channel model.

NCAR scientists have examined the historical record of tropical cyclones in the North Atlantic for long-period variability and trends in frequency. Future plans include extending this work to other ocean basins. NCAR scientists also will utilize the new NCAR NRCM to examine the environmental changes associated with these observed trends and variations of tropical cyclones.

On the following pages, we report on some of the highlights related to this priority.