Numerical Investigation of the Role of Topography in Tornado Events in Greece

Abstract

Several tornadic events have been reported in Greece during the last decades and are usually associated with strong synoptic scale forcing. Although most of them occur over the sea (waterspouts), a number of events appear over the land, causing serious damages to the nearby infrastructure and posing an important threat to human beings. It is well known that the meteorological conditions over Greece are affected at various scales by the significant variability of topography. However, there is still uncertainty regarding its importance on tornadoes. The aim of this study is to investigate the relative role of topography and synoptic scale forcing in the occurrence of tornadoes in Greece. Two events that occurred during the last years at Thiva (Boeotia, 17/11/2007) and Vrastera (Chalkidiki, 12/02/2010) were selected for numerical experiments. These events were associated with frontal activity and caused serious damages. The non-hydrostatic WRF-ARW atmospheric numerical model is utilized at very high resolution using telescoping nests in order to perform the sensitivity experiments. Two sets of experiments are conducted: (a) with the actual topography and (b) without it.