Thunderstorm outflow characteristics in the Beijing urban area

The study of thunderstorm outflows and their effects on structures is a key topic in modern wind engineering. Based on the in-situ monitoring network in the northern Mediterranean carried out for the European “Wind and Ports” and “Wind, Ports and Sea” projects, the key characteristics of thunderstorm outflows in this area relevant to wind engineering with special concern for the wind loading of structures were analyzed in previous researches. Recently this work has been repeated and extended to the dataset detected by 9 anemometers installed at different levels on the Beijing 325 m high meteorological tower. This provides a unique opportunity to study the characteristics of thunderstorms in the Beijing urban area, to compare these with northern Mediterranean ones and to understand if thunderstorms in different areas have similar properties. Herein, the extraction and the cataloguing of thunderstorm outflows are illustrated firstly and then the directional signal decomposition strategy, in which their horizontal resultant velocity is decomposed along time-varying longitudinal and lateral directions, are presented. These analyses are preliminary for the further study and comparison of their characteristics.