First radar detection of a misocyclone in a UK tornadic storm

Abstract

fully developed to an underlying urban area. Laboratory experiments would enable more controlled measurements that would complement such an observational programme. Many urban areas are too small for the boundary layer to adjust fully, so that it is important to investigate the transition from rural terrain to the urban area. Here large-eddy modelling is the crucial tool, perhaps starting by investigating how the boundary layer responds to simple changes in surface properties. New theoretical concepts are required if the urban areas are to be parametrized effectively both in the largeeddy modelling studies and NWP. Here the expertise amongst the UK community developed in studying boundary-layer flow over hills and through vegetation canopies might well provide clues. Methods for representing the average effects of vegetation on the boundary layer as 'canopies' are now reasonably well developed, and a similar approach to representing buildings within urban areas might prove fruitful. Results from these theoretical studies could suggest further large-eddy model simulations and thence further observational studies. These studies of mixing and transport in urban areas will provide the basis for studying the complex chemical transformations that control pollutants from urban sources. Clearly such an integrated programme of work requires careful co-ordination and planning. UWERN is the ideal vehicle to perform this task.