Public Release: 

The Sunspots Are Coming

National Science Foundation


Scientists To Debate Year 2,000 Solar 'Max' Effects On Earth

Atmospheric scientists participating in a workshop funded in part by the National Science Foundation (NSF) will debate the effects of so-called "space weather" on earth's navigation and communication signals -- two of the major systems affected by an upcoming "solar max." The workshop will take place in Bethesda, Maryland, at COMSAT Corporation, from October 22-24, 1997.

Moving through its eleven-year activity cycle, the sun will be in its most active state around the year 2,000, with manifestations of the "solar max" (better known as the peak of the sunspot cycle) persisting through the early years of the next decade.

"Space weather" refers to conditions on the sun, in the solar wind, and in earth's atmosphere that can influence the performance and reliability of space-borne and ground-based technological systems, and can endanger human life or health. Adverse conditions in the space environment, say atmospheric scientists, can cause disruption of satellite operations, communications, and navigation and electric power distribution grids, leading to a variety of socioeconomic losses.

The workshop will bring together space-weather modelers, atmospheric researchers, systems engineers and operators, and others whose navigation and communication systems employ signals that propagate through the ionosphere, the layer of earth's atmosphere above the stratosphere.

As the turn of the millennium nears, emerging human technologies and a natural cycle that has existed for eons will converge in unknown ways, according to NSF's Sunanda Basu and other atmospheric scientists organizing the workshop.

The human world has changed much since the last solar 'max,' in 1989, explains Basu. No longer does the potential for global armed conflict dominate technological development, particularly for applications in navigation and communications. The Global Positioning System (GPS), for example, is becoming ubiquitous, and some of its applications more demanding of accuracy. A plethora of communication systems is emerging, says Basu, including many that employ VHF and/or UHF bands for links via the ionosphere.

Abrupt variations in solar ultraviolet radiation and in the solar wind that interact with earth's atmosphere are "space weather" events that strongly perturb the ionosphere, according to Basu, and result in many propagation anomalies. "Such events will become increasingly common and severe as we near the solar-activity maximum that will occur during the years spanning the turn of the century."

The workshop will provide two-way interaction between space weather scientists and the designers and operators of communication, navigation, and other systems that depend on radio wave propagation.

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