Climate indicators of variability analysis to pluvial precipitation in Rio Grande do Sul

Foram calculados dez ??ndices de freq????ncia e de intensidade da precipita????o pluvial a partir de dados dessa vari??vel, de treze esta????es meteorol??gicas bem distribu??das no Rio Grande do Sul, para os meses da primavera e ver??o, entre 1961 e 2005. Atrav??s de um modelo de regress??o linear simples foram determinadas as tend??ncias desses ??ndices e foram considerados aqueles com no m??nimo 5% de signific??ncia. Foram feitas an??lises de eventos extremos de precipita????o e das tend??ncias dos ??ndices pluviom??tricos. Os resultados de eventos extremos n??o permitem identificar um padr??o de comportamento espacial da precipita????o pois s??o eventos pontuais. A an??lise de tend??ncia da intensidade da precipita????o indica que a variabilidade desses ??ndices ?? muito pequena nos meses do ver??o e mais significativa no m??s de outubro, onde percebe-se um aumento em todos os ??ndices de precipita????o nas cidades da regi??o Norte/Nordeste do Estado. Fica evidente a variabilidade significativa na freq????ncia dos dias consecutivos sem precipita????o e na de dias muito secos, indicando tend??ncia de aumento desses ??ndices no m??s de mar??o e de decr??scimo nos demais meses do per??odo analisado. Nos demais ??ndices a variabilidade foi muito pequena n??o indicando, conseq??entemente, grandes altera????es no padr??o de comportamento da vari??vel precipita????o pluvial.Ten frequency and intensity of the pluvial precipitation rates were calculated from this variable date, from thirteen well distributed meteorogical stations at Rio Grande do Sul, during the spring and summer months, between 1961 and 2005. Through a simple linear regression model were determinated these tendencies rates and were considerated those with at least 5% of significancy. Extreme precipitation events and pluviometric rates tendencies were analysed. The extreme events results do not allow to identify a precipitation spatial behavior through them because they are punctual events. The precipitation intensity tendency analysis indicates that the variability of these rates is very small during the summer months and more significant during october, where all precipitation rates increase in the North/Northeast region. It is evident the significant variability in the consecutive days without precipitation frequency and in those very dry, indicating the increase tendency in these rates in march and decrease in the other months within the analysed period. In the other rates the variability was very small not indicating consequently, high variability on the precipitation pattern pluvial precipitation variable behavior patern alteratio