Pluviometric behavior of the city of Porto Velho –RO, Brazil

Understanding the pluviometric variability of a region is necessary to analyze the existing climatological behaviors. The municipality of Porto Velho has a seasonality with high rainfall rate, which occurs at certain times of the year, but in recent years, the region has undergone climate change, which directly interfere in its hydrological cycle. This event is relate to the natural climate actions coming from the Pacific Ocean, but these events can be accelerated or modified due to anthropic actions that encompass land use and high rate of greenhouse gas emissions. Therefore, the present article aims to analyze and understand rainfall variables from 1961 to 2015, through data obtained from the National Water Agency database of the Hidrometereological station of Porto Velho – RO. When analyzing these data, it was possible to identify that the months with the highest precipitation rate are December, January, February March and April, as well as it was possible to identify that the annual average precipitation rate was 1736 mm, and that the biennium periods had influences of the El Niño and La Niña phenomena regarding their pluviometric volumes. It was also possible to observe that the region of studies present two well-defined seasons, one rainy and one dry, so the present study was able to observe the pluviometric behavior existing in the region during these 54 years.