There has been strong interest in recent years in applying the notions of circulation regimes, weather regimes and weather types to a variety of time scales and applications, from weather forecasts to intra-seasonal anomalies to climate impacts.

The spatial scales covered by diverse classification schemes range from regional to hemispheric. There has also been an interest in applying weather types to such diverse subjects as pollution concentrations and human mortality. The purpose of the workshop will be to bring together researchers who apply classification techniques to describe and verify weather forecasts, climate anomalies over a range of time scales, and applications of human dimension.

The variety of mathematical and statistical techniques used will be presented, leading to cross-fertilization of techniques and methods.

Topics of interest will include:
• What are the common techniques used to describe large-scale circulation regimes and local weather types (e.g.cluster analysis, hidden Markov method, pdf analysis), and how are they related to each other?
• How are regimes used to characterize and verify forecasts from operational forecasting centers?
• How much is really understood about measuring the significance of deviations from Gaussian behavior, and the robustness of clustering / weather typing?
• Will climate change lead to an alteration of the frequency of occurrence of well-define regimes, or the modification of the whole regime structure?
• How can we describe coherent propagating structures, such as the Madden-Julian Oscillation (MJO) and the Monsoon intra-seasonal oscillation (ISO) in terms of regimes? “Hands-on” training sessions will be held in weather typing and circulation regime analysis, using data sets such as ERA-40 or NCEP reanalyses, and simple classification techniques which can be applied to their home regions for problems of local interest.