CONTRIBUTION OF EARTH OBSERVATION TO UNDERSTANDING THE UPWELLING CONDITIONS OF THE SW COAST OF PORTUGAL

摘要

Validation of MERIS (Medium Resolution Imaging Spectrometer) satellite products in the coastal upwelling system off the SW coast of Portugal has occurred since 2008 over a series of sampling campaigns at Stations 2, 10 and 18 km offshore. Data from between the 4~(th) October and the 17th November 2008 demonstrate an upwelling event where temperature declines markedly from 20°C to 16.5°C between the 26~(th) October and the 8th November. Other data confirming these events are profiles for conductivity, temperature and depth, as well as nutrient and chlorophyll concentrations. Nitrate peaks with chlorophyll on the 8th November, but phosphate is at low concentrations and declines before those of the nitrate over this period. The more spatially extensive sea surface temperature combined with wind velocity and direction, as well as MERIS Algal 1, supports the more site-specific observations at the validation stations. Nutrient changes due to physical forcing from upwelling occur earlier than changes in chlorophyll concentration.