Introduction

    In an effort to create the best possible quality-assured ozone record, the WMO/NASA International Ozone Trends Panel in 1988 called for a complete re-evaluation of the long-term ozone record based on calibrations and auxiliary information which was not done systematically before. This was strongly endorsed by the Executive Council of the World Meteorological Organization (WMO). To stimulate relevant action the National Oceanic and Atmospheric Administration (NOAA) took the initiative under the Information Management Element of the NOAA Climate and Global Change Program. As a result, three international workshops addressing the state of the total ozone data set obtained by the global network of Dobson spectrophotometer stations have recently been held, in collaboration with WMO and the International Ozone Commission (IOC) under the Co-chairmanship of Prof. Robert D. Hudson and Dr. Walter G. Planet.

    The First International Dobson ozone Data Workshop was held September 11-13, 1991, in the Washington D.C. area. The workshop participants discussed the shortcomings of the existing data set and the need for a revised, more accurate and coherent data set useable for climate trend analyses and also for satellite comparisons. The participants recommended (see WMO Ozone Report #24) a second workshop where those who have already re-analysed their data sets would present their procedures and results to those station operators who have not yet begun re-analysis of their own data sets or who have applied incorrect procedures.

    The Second International Workshop was held June 1-3, 1992, in conjunction with the Quadrennial Ozone Symposium at Charlottesville, Virginia. The major recommendation of the participants of this Second Workshop was to prepare a Handbook which will contain procedures, algorithms, etc. useful for re-evaluating historical Dobson data sets. Primary authors and contributors were solicited from the international Dobson community.

    The draft of the Handbook has been reviewed by a significant segment of the Dobson community including participants at the Third workshop held at Hradec Kralove, May 24-28, 1993. Thereby, it should be considered a library reference alongside previous publications which have become standard over the years.

    This Handbook follows the consensus of the participants of the Third Workshop and, therefore, could be considered a collective effort although the personal contributions in drafting and collating the sections of this Handbook by Rumen D. Bojkov, Walter D. Komhyr, Alan Lapworth and Karel Vanicek should be explicitly acknowledged.

Robert D. Hudson and Walter G. Planet
Co-chairmen of the Workshops and Editors

Section 1

Section 2

Section 3