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Proceedings of the NATO Advanced Research Workshop on Prediction of Interannual Climate Variations held at Trieste, Italy, July 22-26, 1991

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It has been known for some time that the behavior of the short-term fluctuations of the earth´s atmosphere resembles that of a chaotic non-linear dynamical system, and that the day-to-day weather cannot be predicted beyond a few weeks. However, it has also been found that the interactions of the atmosphere with the underlying oceans and the land surfaces can produce fluctuations whose time scales are much longer than the limits of deterministic prediction of weather. It is, therefore, natural to ask whether it is possible that the seasonal and longer time averages of climate fluctuations can be predicted with sufficient skill to be beneficial for social and economic applications, even though the details of the day-to-day weather cannot be predicted beyond a few weeks. The main objective of the workshop was to address this question by assessing the current state of knowledge on predictability of seasonal and interannual climate variability and to investigate various possibilities for its prediction.

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1: Reviews.- Observational and Modeling Studies of the Influence of Soil Moisture Anomalies on Atmospheric Circulation (Review).- Observational and Modeling Studies of the Influence of Land Surface Anomalies on Atmospheric Circulation (Future Directions).- Review of Recent Advances in Dynamical Extended Range Forecasting for the Extratropics.- Observational and Modeling Studies of the Influence of Sea Ice Anomalies on the Atmospheric Circulation.- Observational and Modeling Studies of the Influence of Snow Anomalies on the Atmospheric Circulation.- 2: Coupled Models.- Coupled TOGA Models at the UKMO.- Toward the GCM El Ni¤o Simulation.- 3: Low-Frequency Variability.- Interannual Climate Variations Over the Tropical Atlantic Ocean.- Low-Frequency Variability and Blocking as Diagnostic Tools for Global Climate Models.- 4: Present Status of Seasonal Forecasting.- Operational Seasonal Prediction at NMC.- Experimental Seasonal Forecasting of Tropical Rainfall at the U.K. Meteorological Office.- 5: Predictability.- Predictability of Short-Term Climate Variations.- Predictability of Climate.- On the Problem of Prediction Beyond the Deterministic Range.

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