Frequency and Intensity of Extreme Rainfall Events From 1961 to 2010 in Distrito Federal, Brazil (PAP014715)

Código

PAP014715

Autores

Pablo Borges de Amorim, Klemens Barfus, Holger Weiss, Christian Bernhofer

Tema

Floods in a changing climate

Resumo

Due to rapid and unplanned urbanization and changes in land use, the capital of Brazil is already experiencing a high risk to negative consequences caused by floods. The understanding of processes involved in risk reduction is essential to achieve the goals of reducing damages (i.e., life, food production, sanitation, transport, etc). The hazard is often inevitable and society is pushed to take actions on adaptation strategies to reduce vulnerability. However, reliable adaptation measures are based on information about the hazard, for instance the frequency and intensity of events. Potential changes in the variability of future regional precipitation may enhance impacts caused by floods; however, rainfall projections are still very uncertain. This in mainly due to the lack of capacity of global circulation models - GCMs in simulating the amount of rainfall influenced by convective systems. In order to provide valuable information about flood hazard in Distrito Federal, as well as interpret the results of GCMs, the assessment of rainfall extreme events is needed. Since rainfall is directly related to runoff, precipitation is one of the main drivers of flood hazard. For that, frequency and intensity of rainfall from 15 rain gauges are analysed. Rainfall extreme events can be measured by indices, such as the 95th percentile of the year, number of days for which precipitation rate exceeds 20, 40 and 60 mm; and maximum 5-day precipitation total. Results show that most of the rain gauges analysed present a fairly significant positive trend in the frequency and intensity of extreme rainfall. Independent on the causes of that, this information is valuable to support decision makers in taking action to minimize damages caused by flood events.