Biennial Scientific Report 2001 – 2002

Contents Preface Foreword Recent highlights On the role of cirrus clouds in climate 11 Pathways in the ocean 19 Monitoring of tropical processes relevant to climate change 29 Current projects Preface • In 2001 the Intergovernmental Panel on Climate Change (ipcc) published its Third Assessment Report (tar). It was concluded that " There is new and stronger evidence that most of the warming observed over the last 50 years is attributed to human activities ". Moreover " Confidence in the ability of models to project future climate has increased ". With these significant conclusions climate change continues to be an important issue on the scientific and political agenda. Baede, who retired. By continuating its own research and by participating in various national and international networks and programmes, the Department continued to contribute to further understanding of the global climate system. Foreword • knmi has a long tradition in research of the atmosphere, the ocean and the solid earth. With the establishment of a separate Climate Research and Seismology Department in 1995 knmi has focused most of its research on the issue of climate change. The climate research strategy developed over the years. The current programme is based on three criteria, namely 1) the questions that knmi receives from society; 2) the current scientific challenges in climate research; and 3) particular expertise available at knmi. The result is a programme centred around three broad themes, namely monitoring, understanding and prediction of climate variability and change. Work is carried out in a five specialised divisions, in close collaboration with other knmi departments, and many national and international research institutes. To increase the coherence of the research programme a number of interdivisional projects was started in 2002. One of these will coordinate activities related to Monitoring of the Atmospheric Composition from Satellites, another is concerned with Patterns of Climate Variability, and a third deals with Regional Climate Prediction. At the end of 2002 these projects were in different stages of start-up. The Seismology Division has both an operational and a research task. Operationally, it is responsible for the monitoring of seismic events. Its research programme focuses on seismic risk for both natural and induced events. In addition it has a programme on atmospheric infrasound and activities related to the implementation of the Comprehensive Nuclear-Test-Ban Treaty. This fourth Biennial Report follows the format of earlier reports: three Recent Highlights are followed by Progress Reports …