Extreme rainfall in alegrete (rs): a study on the occurrence in the twentieth century

Abstract

The 5th Assessment Report of the Earth Climate Change (AR5) of the Intergovernmental Panel on Climate Change (IPCC) says that extreme precipitation events will become more intense and frequent until the end of the XXI century. This study aims to identify the frequency, absolute and relative, of intense precipitation events and their time of return for the surrounding region of meteorological stations of Alegrete (RS) in the twentieth century. Daily rainfall data from stations of the Agencia Nacional de Aguas (ANA) in the period of 1928-2009 were used in this study. The results indicated that rainy days with between 50mm and 80mm are common every year. Days with rainfall >= 100mm occur once a year. Days with rainfall >= 150mm, >= 160mm, >= 170mm and >= 180mm respectively show recurrence time of 8 years, 21 years, 27 years and 82 years. These intense events are responsible for part of the dynamics of sandization in Alegrete (RS).