481: Effects of surface features on thunderstorm activity- a preliminary study for Lisbon region.

Abstract

In this paper some preliminary results of a study on the influence of surface features on convective precipitation and thunderstorm activity in the region of Lisbon (Portugal) are presented and discussed. The present work focuses on a case study - the strong thunderstorms affecting Lisbon on the 9th September 2009. The spatial distributions of precipitation and cloud-to-ground discharges (CGD) are investigated in relation to land surface characteristics, orographic features and other geographical factors. The spatial distributions of thunderstorm activity are also compared with the fields of surface turbulent heat fluxes, derived from satellite data. The datasets have been integrated in a Geographical Information System (GIS) in order to facilitate a georeferenced data analysis. The analysis of modelled and observational data indicates a more intense thunderstorm activity over the Lisbon metropolitan region than on the surrounding areas during this episode. The present work results suggest that the study of the influence of Lisbon urban area on convective precipitation and thunderstorm activity deserves further investigation. More events should be analysed in order to understand the relative importance of Lisbon urban surface on atmospheric convective phenomena. The lack of more adequate observational and modelled data was an important constraint for this work. However, we expect that data with higher spatial and temporal resolution will become available.