Aerosol Workshop — June 2-3, 1997
Session 1: Objectives and Approach
Robert Curran, NASA Headquarters
The effect of atmospheric aerosols on climate is recognized as being one of the greatest sources of uncertainty in our understanding of long-term climate change. NASA, as well as other agencies in the United States and elsewhere, have made large investments in past, current and future satellite measurements, some of the measurements being explicitly focused on aerosols.
A primary objective of the workshop is to investigate what progress in our understanding of aerosols and climate can be extracted from this existing investment. What information is missing from currently available measurements? Can other agencies or countries be expected to fill in missing data? Are there model assimilation experiments that should be carried out with existing satellite data? Can such experiments, in addition to advancing our understanding of aerosol effects on climate, help to define future sensor needs?
Secondary objectives of the workshop include taking an end-to-end look at the role of aerosols as a climate forcing. Although the focus will be on satellite data, there should be some time to address other issues. We would like to document a research approach as an input to the NASA Aerosol Research Plan. We would also like to address and coordinate with the aerosol research plans of the other agencies, to help get the most out of increasingly scarce federal science funding.
James Hansen, NASA Goddard Institute for Space Studies
The rationale for the broad scope of the workshop is the following. First, the indirect aerosol effect on climate (via changes of cloud properties), as well as the direct aerosol radiative forcing, must be considered, because the indirect effect is potentially the larger climate forcing. Second, combinations of satellite observations, in situ data, and appropriate modeling are required, because of the high precision with which aerosol and cloud changes must be specified in order to define the radiative forcing.
The scientific target of the workshop is "quantitative definition of the global distribution of aerosol (direct and indirect) radiative forcing for the period of satellite data (approximately 1980 to the near future) using satellite data, modeling/analysis and whatever else is available".
The short-term product being sought is guidance to NASA for the preparation of a NASA Research Announcement (NRA). The NRA will seek proposals which contribute to the above scientific objective. It is expected that the first stage of this research initiative will rely on available and planned satellite observations and field experiments, and that the workshop will focus on how to get more out of satellite data with the help of modeling and analysis. Thus the workshop itself will not focus on defining field measurement programs, but the research supported is expected to help define necessary future field programs that may be included in a team research approach.
Desired outcomes include: 1) bright ideas (strategies) on how to quantify (and confirm) aerosol climate forcing, 2) productive interactions/cooperation between specialized groups [satellite <=> global modeling <=> in situ data <=> small scale modeling], and 3) interagency coordination/cooperation in the implementation of a complete aerosol/climate program, including field programs and long-term monitoring.