【学术报告】Dr. Guannan Hu, University of Hamburg

Abstract: The provision of accurate parametrizations is a task of paramount importance in many scientific areas, and specifically in weather and climate modelling. Parametrizations are needed for representing accurately and efficiently the impact of the scales of motions and of the processes that cannot be explicitly represented by the numerical model. Parametrization are usually constructed in order to optimize the overall performance of the model, thus aiming at an accurate representation of the bulk of the statistics. Nonetheless, numerical models are key to estimating, anticipating, and predicting extreme events. Here we analyze critically in a simple yet illustrative example the performance of parametrizations in describing extreme events and we conclude that good performance on typical conditions cannot be in any way extrapolated for rare conditions, which could, nonetheless, be of great practical relevance.