CGD Director's Message from James Hurrell

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The Annual Scientific Report (ASR) highlights the major research accomplishments of the past year, and there are many to report from the Climate and Global Dynamics Division (CGD) of NCAR. The accomplishments are strongly aligned with and supportive of the vision and mission of the institution, and they reflect the hard work and dedication of the entire CGD staff as well as the indispensable contributions of many colleagues from the university, government and international research communities. I am proud and honored to be working with such a great group of people.

Our mission in CGD is to: (1) obtain a comprehensive understanding of the Earth’s climate system components and the interactions among them; (2) to represent this understanding in models of the components and of the coupled system; and (3) to further our understanding by applying the models to scientific and societal questions and thereby provide a basis for prediction of weather and climate. Over the past year, we continued to fulfill this mission through a strong record of achievement in scientific research, community modeling and data set development. We are also very proud of our community service, leadership of national and international research programs, and educational and outreach activities. Accomplishments in these areas are detailed throughout the ASR.

A major focus of divisional activities over the past year was improving the Community Climate System Model (CCSM). Enhancements to versatility and sophistication were made in all individual model components: atmosphere, land, ocean and sea ice. The latest version of the model, CCSM3, is being used for a wide variety of studies concerning climate variability and climate change. Most prominent among these are key simulations for the next major assessment of the Intergovernmental Panel on Climate Change (IPCC). These simulations were not only done at NCAR in 2004, but at several Department of Energy (DOE) labs as well as the Earth Simulator in Japan. Such collaborations allowed for larger ensembles of simulations at higher resolution for longer periods of time than would have otherwise been possible. The IPCC integrations also included important provisions for model data needed by groups interested in impacts, mitigation, and regional modeling at high resolution.

Coordinated by a Scientific Steering Committee (SSC) consisting of both NCAR and external scientists, the CCSM project runs under NSF and DOE sponsorship at NCAR. In addition, NOAA and NASA play important roles through the U.S. Global Change Research Program and U.S. Climate Change Science Program. In June 2004, CCSM3 was released to the worldwide community. The release included a comprehensive suite of control integrations, including simulations of present-day and pre-industrial conditions at three different model resolutions. The new release was also designed to be very portable across a variety of computer architectures.

The 9^th Annual CCSM user workshop was held in Santa Fe, New Mexico in July 2004.&; Attendance, which has increased every year, exceeded 330 participants, more than three times the number of attendees at the first workshop in 1996. University scientists represented the largest group (135), followed by NCAR (120) and DOE (49) scientists. The SSC began planning of the next major scientific directions for the project. One important theme is process-oriented high-resolution modeling targeted at remaining systematic biases in CCSM3 integrations. The second major thrust is the development of a first generation fully coupled climate-chemistry model. This system will include the physical components in CCSM, along with new modules for prognostic aerosols, isotopes of water and carbon dioxide, reactive gas chemistry, oceanic and terrestrial biogeochemistry, and chemical transport. All of these modules were under active development in 2004.

In addition to efforts supporting the development and continuous improvement of a comprehensive climate modeling system, CGD scientists made significant advances toward increased understanding of atmospheric and climate variability and climate change through the parallel development and analysis of observational, assimilated, model-generated and model-forcing datasets, and the application of these datasets in empirical studies and diagnostic analyses to document comprehensively climate variability, its causes and the processes involved.

Major new advances were made by CGD scientists and collaborators in 2004 in our understanding of the diurnal cycle of precipitation, the mechanisms responsible for interannual and longer variations of major climate phenomena such as the El Niño-Southern Oscillation (ENSO), monsoons and annular modes, extreme events, and multi-decadal variations throughout the Pacific. Accomplishments over the past year also include comprehensive diagnostic studies of the global and regional atmospheric moisture, heat, and energy budgets; observational analyses of upper ocean and sea ice variations; new analyses of the total mass of the atmosphere and its variations globally; a new look at the flow of energy through the climate system; new knowledge and insights into several aspects of the global water cycle, droughts and their historical variability; increased scientific understanding of land-atmosphere interactions, and in particular surface forcing of climate; advances in documenting and understanding climate variability over the past millennium, as well as much farther back in time; understanding the sources of predictability in the tropical Atlantic region; and in applying concepts and methodologies developed by the climate dynamics community to diagnose and interpret climate change scenarios.

CGD scientists also played leadership roles in 2004 in designing and advocating the global climate observing system and articulating the need for and benefits of a climate information system; in evaluating, improving, restructuring, and computing high-level derived products from climate datasets including atmospheric reanalyses; developing advanced data assimilation techniques, including work as part of the NCAR Data Assimilation Initiative; and advancing assimilation techniques for biogeochemistry and carbon cycle studies. Also, through both the CCSM3 climate change simulations and other analysis efforts, CGD scientists became heavily involved in the next IPCC assessment as convening lead authors, lead authors and contributing authors, consistent with the mission statement of NCAR.

Finally, I would like to note that many of these accomplishments came under the leadership of Maurice Blackmon, who took on a special assignment for the NCAR Directorate in June of 2004. Maurice faithfully served CGD as Division Director for the better part of a decade, and under his watch the program flourished. Thank you, Maurice, for your hard work and dedication.

Sincerely,

Jim Hurrell
CGD Director