Homogenization has become one of the basic elements of climatological studies. Beside the well-known use in the climate change studies, more and more users request long-term time series in homogenized form. Not only is this positive development the result of the work of the enthusiastic colleagues active on this field for a long time, but also the new observation methods. The overall trend shows a decrease of human observations, growing rate of automatization. In consequence, often we do not measure the same meteorological parameter, than earlier, only something similar to that, certainly new methods of observation are used, which imply rather different data quality problems, etc. The merging of satellite and radar information into the classical database could effect large breaks as well.

The further development needs to solve a number of problems. It is not evident for everybody, that big differences can exist between two time series that originate from the same data, but were homogenized with different methods. The same is valid for the controlled and corrected data using different quality control methods. Comparison of different methods is still missing. The overall practice is to select according to the metadata, which is often missing, because registering metadata was a neglected field of climatology for long, just like homogenization itself. Therefore, on one side comparative studies are requested, and on the other side, the method of homogenization has to be adjoined to each homogenized time series.

Among the numerous unsolved tasks and main problems of homogenization, the homogenization of daily data is to be emphasized:
it is rarely addressed and poses significant problems.

Therefore it can be concluded, that there is a valid request for the seminars with similar topic in the future, and the organizers were pleasantly surprised when the representative of WMO and the President of the hosting institute (HMS) stressed the same idea: this seminar is organized traditionally in Budapest. We promise to do all our best to keep this tradition alive, and to assure a platform of practice and exchange of experience for interested scientists. The Organizers are proud of the further support of this international scientific seminar.

We wish success for studying the presentations given on the 3rd seminar and are looking forward to meet you on the fourth one in Budapest, in 2003.

The Organizers