STATEMENT OF TASK
An ad hoc committee will plan and conduct a public workshop that will examine the state of knowledge regarding the climate response to solar variability and will explore some of the outstanding scientific issues that might guide future research thrusts.
The committee will hold a data-gathering meeting in the process of developing the agenda for the workshop and defining the specific topics for invited presentations and discussions. The committee will subsequently select and invite speakers and other participants and moderate the discussions at the event. The committee will prepare a workshop report that will summarize what transpired at the event but will not contain any findings or recommendations.
The committee will consist of 10-14 people who will meet once in person in early summer 2010 to plan the workshop, which will be open to the public. The workshop itself will be held in late fall 2010 over 3.5 days and will include approximately 25 invited participants. After the workshop, a short summary report without findings or recommendations will be produced.
Prior to its first meeting, the organizing meeting will review with the study sponsors and with the director of the Board on Atmospheric Sciences and Climate potential topics for discussion at the workshop. Based on discussions to date with NASA, the following is a tentative list of questions to be addressed at the workshop:
• What part of observed atmospheric variability is in response to solar forcing, particularly in the lower atmosphere? Are attributed signals consistent over different timescales?
• What are the associations between sunspots or cosmogenic isotopes and the magnitude of solar irradiance changes in the past?
• If long-term solar irradiance variations are insufficient to impact climate, were other solar-modulated parameters, such as galactic cosmic-ray flux, responsible for the reported paleo Sun-climate connections?
• Is empirical evidence sufficient to conclude that the spatial response in climate models is consistent or not? What does the evidence imply about the relative roles of the Sun and greenhouse gases (GHGs) in past, present, and future climate change, and what does this mean for projections of regional climate response to other radiative forcings, such as GHGs?
• What are the research directions and model extensions necessary to improve the models, using solar forcings and observed climate responses to test their fidelity?
• Are the long-standing concepts of radiative forcings and responses that are the basis for the models adequate to accommodate the actual physical processes?
• What are the research needs in the near term to inform the next Intergovernmental Panel Climate Change assessment?