Climate And Weather of the Sun-Earth System

A new SCOSTEP Program for 2004-2008


Scientific Motivation for CAWSES

There are both purely scientific and applications motivations for identifying and producing an improved understanding of variations in the Sun-Earth system. The Earth, solar system, and beyond provide the cosmic environment in which humankind lives. The quest for applying research and technological tools to secure a better understanding of the human environment is perennial. Achieving sufficient understanding of our solar-terrestrial environment is of great practical significance.There is evidence that changes in the Sun potentially influence climate on Earth. Also the heightened sensitivity of increasingly sophisticated technology to fluctuations in the solar-terrestrial environment makes it increasingly important to be able to forecast adverse conditions, or analyze the features of the disturbed system that cause operational problems.

Although present concepts of the solar-terrestrial environment identify separate physical domains – Sun, heliosphere, magnetosphere, thermosphere/ionosphere, middle atmosphere, and the lower atmosphere climate system – in fact the solar-terrestrial environment is a system whose state at any given time and at any specific location typically results from a linkage of multiple physical processes that occur simultaneously or sequentially in many domains.

For example, variability on decadal time scales permeates the terrestrial and space environments. There are multiple solar sources of this variabilitySolar radiation is the major source of terrestrial energy.The rise and fall of the Sun's 11-year activity cycle causes terrestrial temperature and density changes, especially in the thermosphere. Significant changes also arise from the cumulative effects of geomagnetic storms, as clouds of charged particles propagate through the heliosphere and input energy more or less efficiently to the magnetosphere and the polar regions of the atmosphere with seasonal changes in Earth's orientation and during maximum and descending phases of the solar cycle. Solar wind modulation of the interplanetary environment alters the interaction of the magnetosphere and upper atmosphere with energetic solar particles and galactic cosmic rays, and produces additional fluctuations, as well as those produced by internal dynamical oscillations within terrestrial regimes. Long-lasting human habitation in space is in its early beginning phase, and there is much to learn about how life there will succeed. Our experiment with human habitation on Earth is much longer-running, but there is still much to learn about how interactions between the Sun and Earth can affect it, and how to distinguish between natural variations and anthropogenic ones.

CAWSES Office, Center for Space Physics, Boston University, 725 Commonwealth Ave. Boston, MA 02215 USA; Phone: 617/353-5990; FAX: 617/353-6463;