Organization: National Science Foundation (NSF)

Research Title: Solar Influences

Funding Level (millions of dollars):

FY94 5.9
FY95 6.1
FY96 6.0

Committee on Environment and Natural Resources (CENR) Component:
(a) Subcommittee: Global Change Research Subcommittee (100%) NSTC Committee on Fundamental Science
(b) Environmental Issues: Natural Variability (50%); Greenhouse gases (30%); Exploratory (20%)
(c) Research Activity: System structure and function: Understanding (100%)

Organizational Component:
Directorates for Geosciences and Mathematical and Physical Sciences
Division of Atmospheric Sciences
National Science Foundation, 4201 Wilson Boulevard
Arlington, VA 22230

Point of Contact:
Richard A. Behnke
Phone: 703-306-1518

Research Goals:
To observe and understand the mechanisms that give rise to variable radiative output from the sun, how particles and fields from the sun interact with Earth's magnetosphere and ionosphere, and the coupling, energetics and dynamics of upper atmospheric regions from the mesosphere to the exosphere. The ultimate goal is to develop a predictive capability of the effects of the solar terrestrial environment on the Earth and its climate.

Research Description:
The Solar Influences Program (SIP) at NSF has three elements: 1) studies of the coupling, energetics and dynamics of atmospheric regions; 2) studies of the coupling between the upper atmosphere and the near-Earth space environment; and 3) ground-based observations, theory and analysis aimed at understanding the variable radiative outputs of the sun. The research is based on a synergistic approach involving observations, data interpretation, and theoretical analysis and modeling. Because of the immense size of the physical systems involved, many studies are carried out via coordinated experimental campaigns using a vast array of state-of-the-art optical, radiowave and other types of instruments. The Solar Influences Program has already led to improved understanding and models of the processes governing how energy is coupled through the atmosphere via particle transport, chemistry, electrodynamics and winds. It has been discovered that the mesosphere and lower thermosphere are exceedingly sensitive to changes in greenhouse gas concentrations in the lower atmosphere -- small variations in the greenhouse gas concentrations cause large changes in the temperature of these tenuous high-altitude atmospheric regions. Another vital goal of SIP is to develop an understanding of the solar radiative component of global climate change. In fact, the role of solar variability may have

Program Interfaces:
SIP activities are integral to NASA, NOAA and international civilian space efforts such as EOS, UARS, TIMED, TIROS, and ISTP. Similar connections exist with several DoD satellite missions. DoD laboratories actively participating in SIP include Phillips Lab and the Naval Research Lab. In addition to several hundred university-based scientists, SIP involves scientists from research divisions of numerous industry and non-profit corporations. In addition, SIP supports many cooperative efforts with Canadian, European, Australian, Japanese, and Russian space science communities; for example, SIP has funded a project to establish an atmospheric observatory in the polar cap at Resolute Bay, Canada. The National Academy of Sciences has strongly endorsed SIP and has recommended that appropriate elements be the US contributions to the international Solar Terrestrial Energy Program (STEP). Finally, SIP has a strong educational interface, exemplified by the attendance of over 180 students at a recent 1994 Summer Workshop in Boulder, Colorado.

Program Milestones:
1995-97:: Develop observational capabilities to monitor the variability of the sun's radiative outputs and the solar diameter and develop instrumentation for remote sensing upper atmospheric phenomena; conduct international campaigns coordinated with satellite measurements to study how solar wind energy is coupled through the magnetosphere and upper atmosphere. 1996-1998 Develop physical models for the mechanisms responsible for solar variability and construct a general circulation model for the flow of energy from the solar wind through the magnetosphere into Earth's upper atmosphere; develop a system of models that account for the dynamic interactions between the ionosphere, thermosphere, and lower atmosphere. Monitor the build-up of greenhouse gases through their effect on middle atmosphere temperature by establishing and maintaining a long-term data base.

Policy Payoffs:
Among the important contributions made in the study of solar influences is the recognition that the upper atmosphere is a very sensitive indicator of global warming because changes observed in these tenuous regions are more dramatic. If such sensitive indicators can be adequately calibrated, upper atmosphere observations could become an important element in formulating policies with regard to the build-up of greenhouse gases and the regulation of chlorofluorocarbons. In addition, knowledge gained by studying the natural variability of the sun is essential to establish a context by which the natural short-term changes in the atmosphere may be separated from anthropogenic changes.