The Advanced Study Institute (ASI) under discussion was initiated by the "Special Programme Panel on Radio meteorology" of the Scientific Affairs Division of NATO. The domain of this panel - and consequently the topics of their former ASI-~rogrammes - is the influ ence of the non-ionized atmosphere on electromagnetic wave propagation, its prediction and its use as a re mote sensing technique. It is the final goal to inform radio and radar engineers about the various defects caused by the propagation medium atmosphere. Today there exist high-sensitive radar systems which can pro vide identification and produce images of distant ob jects very accurately by measuring a) the effect of the target on the shape of a short radar pulse, or b) the wave front (phase and amplitude distribution) and its orientation in space. But usuallv the radar-to-target path is through the inhomogeneous and turbulent atmo sphere and so the absolut limits of the system are very often determined by this atmosphere. It was the plan of this ASI to arrange an interdisciplinary information exchange between radar experts and propagation specia lists in order to get a better understanding of the susceptibility to atmospheric effects and to develope new methods that will reduce or correct these errors. The lectures given and especially the intensive dis cussions during the workshop sessions contributed to this aim.

The Advanced Study Institute (ASI) under discussion was initiated by the "Special Programme Panel on Radio meteorology" of the Scientific Affairs Division of NATO. The domain of this panel - and consequently the topics of their former ASI-~rogrammes - is the influ ence of the non-ionized atmosphere on electromagnetic wave propagation, its prediction and its use as a re mote sensing technique. It is the final goal to inform radio and radar engineers about the various defects caused by the propagation medium atmosphere. Today there exist high-sensitive radar systems which can pro vide identification and produce images of distant ob jects very accurately by measuring a) the effect of the target on the shape of a short radar pulse, or b) the wave front (phase and amplitude distribution) and its orientation in space. But usuallv the radar-to-target path is through the inhomogeneous and turbulent atmo sphere and so the absolut limits of the system are very often determined by this atmosphere. It was the plan of this ASI to arrange an interdisciplinary information exchange between radar experts and propagation specia lists in order to get a better understanding of the susceptibility to atmospheric effects and to develope new methods that will reduce or correct these errors. The lectures given and especially the intensive dis cussions during the workshop sessions contributed to this aim.

This foreword deals exclusively with the planning, organization, and execution of the Workshop's scientific as well as cultural programs. It is opened with a synopsis on how the global political changes that occurred immediately after the Workshop caused the ~elay in producing the proceedings, followed by a brief exposition on need, timeliness, and importance of this second ARW in the field of electromagnetic imaging, radar remote sensing, and target versus clutter di~rimination; and an outline of the objectives. An informal discussion about some of the organizational details, a retrospective summary of events, and a preview of the third workshop, planned for 1993 September 19-25, is intended to recapture the spirit of this second NATO Advanced Research Workshop (1988 September 18-24), and will reveal how successful it was in compar ison to the first of 1983 September 18-24, how its accomplishments may be appreciated and why a third and last workshop was requested by its participants to take place during 1993 September 19-25.

These proceedings contain lectures, research papers and working group reports from the NATO Advanced Study Institute on "Surveillance of environmental pollution and resources by electromagnetic waves", held at Spatind, Norway, April 9-19, 1978. Remote sensing of the environment has developed into a very complex multidisciplinary field. It encompasses a huge range of different instrumental techniques and analytical methods, designed to provide information about a vast number of environmental parameters. Nevertheless, the approach to solve specific problems and the ways of handling the collected information are to a large extent the same or similar. This commonality is the basis for the Advanced Study Institute. To provide the best possible background, both tutoria11y and for a fruitful exchange of research ideas and results, a number of outstanding scientists were invited to review some major fields. The material presented in these proceedings is certainly not complete in the sense that it covers all aspects of the subject. The selection is deliberately due to the program committee and the editor. The program committee would like to express their gratitude to Dr. Ti10 Kester, head of the NATO Advanced Study Institute Program, NATO Scientific Affairs Division, for his support and encouragement during the organization of the Institute. Oslo, June 1978.