26 years of SST and upwelling indices data were evaluated in SW Portugal. The aim was to delineate oceanographic seasons based on upwelling regimes. SST increased at components of time series analysis pdf rate of 0. Four seasons of distinct upwelling regimes were identified.

Portugal using statistical analyses of publically available data. US National Climatic Data Center. Time series were extracted at a daily frequency for a time horizon of 26 years. In the first part of the study, time series were inspected for trend and seasonality over the whole period. Structural breaks analysis applied to the time series showed that a statistically significant incremental increase in SST was more pronounced during the last decade. A spectral analysis combined with the previous analysis enabled the identification of four oceanographic seasons. Those seasons were later recognised over a restricted time period of 4 years, between 2008 and 2012, when there was an extensive sampling programme for the validation of ocean colour remote sensing imagery.