The objectives of this study were to test homogeneity, to recalculate the climatology and to detect possible trends, interannual and interdecadal variations in seasonal and monthly secular-historical series of sunshine-duration in Santa Maria-RS, Brazil. Sunshine-duration data were measured at the meteorological station of the Brazilian National Weather Service (8º DISME/ INMET), within the period of 1912 to 2011. The Mann-Kendall and Pettitt tests were used to analyze data homogeneity and trending, respectively. It was observed that monthly and seasonal secular-historical series of sunshine-duration are stationary and homogeneous, except for December and fall season. Moreover, interannual and interdecadal variability were related to the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), with signal from the cold phase of both phenomena, which increases sunshine duration mainly during spring (October and November).
homogeneity; el niño southern oscillation; pacific decadal oscillation; Mann- Kendall
