| Popis: |
Within the framework of ORPAM (03/MAC/4.2/A2) project, five years of AVHRR Sea Surface Temperature (SST) (in °C) (2001-2006) (HAZO station, Azores) and of MODIS Ocean Colour (OC) (chlorophyll a in mg m-3) and SST (2002- 2007) data (NASA/GSFC), allowed the establishment and comparison of the mean surface temporal variability among the Azores, Madeira, and Canaries regions. Results show strong and similar seasonal SST variability patterns with average values ranging between 15°C (winter) and 27°C (summer). Largest SST differences are observed during wintertime (Azores/Canaries-lowest/highest values, respectively). Interannual SST variability shows no defined patterns among the three regions. Ocean Colour seasonal variability varies inversely with SST. In the Azores, spring blooms dominate, followed sometimes by smaller autumn ones. In Madeira, spring blooms dominate. In Canaries, OC means are highest during February and March. Interannual OC variability shows the largest variation in Canaries (summertime). These results suggest strong latitudinal gradient effects. Canaries waters are generally warmest, followed by Madeira, and Azores. Highest OC averages are found in the Azores and Canaries regions. In the latter case, this most likely reflects e.g.: the contribution of the African coastal upwelling; OC algorithms failure in Case 2 waters; and winter mixing processes in the region. |
