Monitoring the effect of upwelling on the chlorophyll <i>a</i> distribution in the Gulf of Finland (Baltic Sea) using remote sensing and in situ data
The spatio-temporal variability of chlorophyl <i>a</i> (Chl <i>a</i>) caused by a sequence of upwelling events in the Gulf of Finland in July-August 2006 was studied using remote sensing data and field measurements. Spatial distributions of sea surface temperature (SST) and C...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Institute of Oceanology of the Polish Academy of Sciences
2012-06-01
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| Series: | Oceanologia |
| Subjects: | |
| Online Access: | http://www.iopan.gda.pl/oceanologia/54_3.html#A4 |
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| Summary: | The spatio-temporal variability of chlorophyl <i>a</i> (Chl <i>a</i>) caused by a sequence of upwelling events in the Gulf of Finland in July-August 2006 was studied using remote sensing data and field measurements. Spatial distributions of sea surface temperature (SST) and Chl <i>a</i> concentration were examined using MODIS and MERIS data respectively. The MERIS data were processed with an algorithm developed by the Free University of Berlin (FUB) for case 2 waters. Evaluation of MERIS Chl <i>a</i> versus in situ Chl <i>a</i> showed good correlation (r<sup>2</sup> = 0.67), but the concentration was underestimated. The linear regression for a 2 h window was applied to calibrate MERIS Chl <i>a</i>. The spatio-temporal variability exhibited the clear influence of upwelling events and related filaments on Chl <i>a</i> distribution in the western and central Gulf. The lowest Chl <i>a</i> concentrations were recorded in the upwelled water, especially at the upwelling centres, and the highest concentrations (13 mg m<sup>-3</sup>) were observed about two weeks after the upwelling peak along the northern coast. The areas along the northern coast of upwelled water (4879 km<sup>2</sup>) on the SST map, and increased Chl <i>a</i> (5526 km<sup>2</sup>) two weeks later, were roughly coincident. The effect of upwelling events was weak in the eastern part of the Gulf, where Chl <i>a</i> concentration was relatively consistent throughout this period. |
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| ISSN: | 0078-3234 |