A variabilidade pluviométrica na Mesorregião do Triângulo Mineiro/Alto Paranaíba-MG

The majority of the productive activities of Mesoregion Triangulo Mineiro/Alto Paranaíba-MG is linked to the primary sector, whose productivity is a lot dependent on rhythm of rainfall. This article reports results of research aimed to verification of the variability of the rain in the annual scales, seasonal, monthly and daily, with featured for determination of the beginning and end of the rainy season and analysis of the frequency of dry spells occurring in that territorial unit. For this, we used data available by the Agência Nacional de Águas (ANA) of 19 pluviometric posts, comprising historical series of 34 years (1980-2013). After the application of tools specific statistics for each of the time scales, it was observed that the beginning of the rainy season occurs predominantly in October (27% of the years analyzed) and the end occurs especially in April (76% of the years analyzed). Inside of the rainy season is common the occurrence of dry spells of intensity predominantly weak to average (7 to 12 days), especially in the months February and March. The majority of the daily rains is weak, occurring below of 10 mm and are less significant for the total of the rainfall heights. The rainfall classified as strong, above 30 mm, have low frequency (13% of the total of the rainfall events), but are responsible for almost half of the annual pluviometric volume