To build aspects of general interest into whole IUGG sections, the
Chief Editor of the U.S. National Report initiated a new category of report,
which is the title of this section. Of seven SPA reports solicited under this
category, five were received. They serve to illustrate that SPA research can
be inherently interesting, can be intrinsically valuable, and can push on the
frontiers of knowledge. They fall under the headings climate change, space
impacts, space utilization, and space exploration. In the first of
these, `The sun-climate question: Is there a real connection?,' George
Reid gives
a balanced presentation of recent work in this controversial but potentially
highly important area. The data bases available to address the question
have expanded over the past two decades until now they support systematic
studies which, combined with numerical modeling of the climate system,
characterize a maturing science. That maturation and the associated
stabilization of the research program on sun-climate effects are summarized
here. Climate change is also the subject of Ray Roble's report: `Major
greenhouse cooling: The upper atmosphere response to increased CO
.'
Compared to other atmospheric gases, carbon dioxide is a good radiator of
heat. By radiating down, it heats the earth and contributes to greenhouse
warming. By radiating into space, it cools the atmosphere above about 50
km. Recent research shows that as atmospheric CO
increases, the upper
atmosphere cools more than the earth heats. The first signs of an
anthropogenic influence on global climate might, therefore, be
detected above 50
km, and may already have been seen. From sun-climate effects the subject
shifts to space weather, the topic of Nelson Maynard's report: `Space
weather prediction.' He recounts the activities over the past several years
that have led to the first numerical codes for operational space
weather prediction and that have expanded into a broad base of
research that is being
organized under the National Space Weather Program. A counterpart to
space weather prediction is space weather control---interacting with the
space environment to control it or modify it or use it---part of the subject of
John Raitt's report: `Disturbing the universe---our piece of it, anyway:
Active experiments in space.' This multifaceted field is yielding results
with important implications for our increasing ability to adapt the space
environment and to adapt to the space environment. The `General Interest'
suite concludes with an item from space exploration. Margaret Kivelson's
`Serendipitous science from flybys of secondary targets: Galileo at Venus,
Earth, and asteroids; Ulysses at Jupiter' reports on the increases in our
knowledge of the space environments of selected planets and asteroids
resulting from their being gravitational stepping stones or visits of
opportunity for well-instrumented spacecraft on their way to conduct
other business.
The general interest reports present space as a place where humans do things and as an environment that does things, at least indirectly, to humans. They invest space with parts and properties and illustrate that it is in the self interest of humankind to bring these phenomena into the sphere of knowledge. The following reports describe areas of basic research where that sphere has expanded in the past four years. The organization follows the traditional SPA division of research into solar and heliospheric, magnetospheric, and aeronomical.