Articles | Volume 12, issue 7
Nat. Hazards Earth Syst. Sci., 12, 2225–2240, 2012
Nat. Hazards Earth Syst. Sci., 12, 2225–2240, 2012

Research article 19 Jul 2012

Research article | 19 Jul 2012

Analysis of intense rainfall events on Madeira Island during the 2009/2010 winter

F. T. Couto1, R. Salgado1,2, and M. J. Costa1,2 F. T. Couto et al.
  • 1Évora Geophysics Centre – CGE, Évora, Portugal
  • 2Physics Department, University of Évora, Évora, Portugal

Abstract. This paper constitutes a step towards the understanding of some characteristics associated with high rainfall amounts and flooding on Madeira Island. The high precipitation events that occurred during the winter of 2009/2010 have been considered with three main goals: to analyze the main atmospheric characteristics associated with the events; to expand the understanding of the interaction between the island and the atmospheric circulations, mainly the effects of the island on the generation or intensification of orographic precipitation; and to evaluate the performance of high resolution numerical modeling in simulating and forecasting heavy precipitation events over the island. The MESO-NH model with a horizontal resolution of 1 km is used, as well as rain gauge data, synoptic charts and measurements of precipitable water obtained from the Atmospheric InfraRed Sounder (AIRS). The results confirm the influence of the orographic effects on precipitation over Madeira as well as the tropical–extratropical interaction, since atmospheric rivers were detected in six out of the seven cases analyzed, acting as a low level moisture supplier, which together with the orographic lifting induced the high rainfall amounts. Only in one of the cases the presence of a low pressure system was identified over the archipelago.