In recent years, much concern has been expressed on the deleterious effects that anthropogenic emissions of acidic pollutants have on ecosystems of both industrialized countries and remote areas of the world. In many of these regions, seasonal snowcover is a major factor in the transfer of atmospheric pollutants, either to terrestrial and aquatic ecosystems or to the more permanent reservoirs of glaciers and ice sheets. The recognition of the role that seasonal snowcovers can thus play in the chemical dynamics of whole ecosystems was recently echoed by the Committee on Glaciology of the National Research Council (National Academy of Sciences, National Academy of Engineering and the Institute of Medicine) which recommended that studies on "Impurities in the snowpack, their discharge into runoff, and management of the problem" be rated at the highest prority level (ref. a). It is in this context that the Advanced Research Institute (ASI) brought together scientists active in the fields of snow physics, snow chemistry and snow hydrology. The programme was structured so as to facilitate the exchange of information and ideas on the theories for the chemical evolution of seasonal snowcovers and snowmelt and on the impact of the chemical composition of the meltwaters on the different components of hydrological systems. As a consequence the ASI also attracted participants from potential users of the information that was disseminated; these were particularly concerned with the effects of snowmelt and snowcover on terrestrial biota and those of lakes and streams.

Seasonal Snowpacks examines the processes which control the chemistry of seasonal snowcover and provides detailed information on the biogeographical distribution of snow (e.g. urban, alpine snowpacks), snow composition (e.g. micropollutants, stable isotopes) or the physical and biological processes which influence the chemical changes in snow (e.g. wind, microbiological activity). The fluxes of chemicals at the snow-atmosphere and snow-soil interfaces are examined, as are processes which modify composition within the snowcover. It is the first book in which the reader will find a comprehensive overview of the theoretical concepts, latest measurement techniques, process-oriented research methods, and models of studies in snow chemistry. The linkages between snow chemistry, atmospheric chemistry and hydrology will make this book of use to both research workers and students in the physical and biological sciences and to natural resource management personnel.

A multidisciplinary 2001 overview of life in, on and under snow for anyone interested in the cryosphere.

various places of the world. Thus, it is hoped that this up-to-date subseries would increase the "awareness" of the world's citizens and encourage governments to devote more attention and resources to address this issue. The series editors thank the international panel of contributors for bringing this timely series into completion. We also wish to acknowledge the very insightful input of the following colleagues: Prof. A. L. Page ofthe University of California, Prof. T. C. Hutchinson of the University of Toronto, and Dr. Steve Lindberg of the Oak Ridge National Laboratory. We also wish to thank the superb effort and cooperation of the volume editors in handling their respective volumes. The constructive criticisms of chapter reviewers also deserve much appreciation. Finally, we wish to convey our appreciation to my secretary, Ms. Brenda Rosier, and my technician, Ms. Claire Carlson, for their very able assistance in various aspects of this series. Aiken, South Carolina Domy C. Adriano Coordinating Editor Preface to Acidic Precipitation, Volume 4 (Advances in Environmental Science) Acidic precipitation and its effects have been the focus ofintense research for over two decades. Initially, research centered on the acidity status and acidification of surface waters and consequent impact on the status of sports fisheries; evidence suggested impacts on fisheries in Sweden and Norway, and in North America, in eastern Ontario, Quebec, and in the Adirondack Mountains of New York.

The cryosphere encompasses all regions of the planet that experiences water in ice form for some portion of the year. In this book, authors Melody Sandells and Daniela Flocco deliver an introduction to the physics of the cryosphere. This includes the Arcti