This international meeting examined the role of sustained, regular measurements in advancing our understanding of the Sun as a large-scale, time-varying system. Observers and theorists cmae together to examine what has been learned from synoptic measurements, to identify scientific opportunities for the next decade, and to discuss technical approaches for exploiting these opportunities. Although the Sun varies on timescales from milliseconds to gigayears, this workshop will focus on phenomena in the solar atmosphere that develop over time (diachronically) on scales of hours to decades. Many of the discussions addressed current problems in solar activity and how synoptic observations help solve those problems, and strategies for defining, collecting, combining, archiving, and interpreting sustained time series of imaged data.
Our understanding of the Sun as a slowly evolving star is imperfect but is under intense investigation by means of neutrino spectroscopy and helioseismology. There are also structures and events that involve subarcsecond angular scales and change on timescales of milliseconds to seconds. Between these extremes lies a range of phenomena that occur on size scales that are a significant fraction of the solar radius and develop on timescales of hours to decades. These diachronic phenomena are central to understanding the solar activity cycle and the behavior of the Sun as a large-scale, coupled system. Such phenomena can be studied advantageously with "synoptic" instruments that are designed to provide regular, accurate, and well-calibrated data over a decade or more -- for example, synoptic magnetographs have revealed more about the magnetic cycle than any other tool. A new generation of synoptic magnetographs, coronagraphs, filtergraphs, and spectrometers has been proposed that greatly exceeds in sophistication and power the "patrol" instruments that have sometimes been associated with synoptic observing in the past. Synoptic measurements from space are powerful new tools for solar research. New techniques for distributing, combining, and interpreting time series of such data will be required to fully exploit the potential of these instruments to elucidate phenomena such as active regions and complexes, global magnetic patterns, coronal structures, and mass ejections.
The main themes of the meeting included:
- current problems in solar activity and how synoptic measurements aid in their solution
- new results derived from synoptic observations
- state of the art of observational techniques and new and proposed synoptic instruments
- coordinating and combining ground- and space-based observations
- enabling easy access to and use of synoptic data
- techniques for modeling diachronic and time-series phenomena
- integration with studies of the solar interior and heliosphere
- future needs and opportunities
K. S. Balasubramaniam, R. Canfield, D. Gary, J. Harvey, D. Rabin, N. Sheeley, A. van Ballegooijen.
The Astronomical Society of the Pacific will publish the prodeeings of this meeting: ASP Conference Series Volume 140, 1998. The editors of these proceedings are K. S. Balasubramaniam, J. W. Harvey, and D. M. Rabin.