Posters

Poster Session 3, Wednesday,  October  5, 16:00–18:00

Poster 79

Use of MODIS satellite data to investigate the spatiotemporal trends of algal and non-algal suspended particulate matter concentrations in Manila Bay, Philippines

The Manila Bay is a semi-enclosed coastal system continuously impacted by anthropogenic influences from the surrounding tributaries. Yet the area has not been monitored using remote sensing satellite data specifically for water quality indicators such as chlorophyll (Chl-a) and suspended particulate matter (SPM).To study the bay’s water quality (WQ) dynamics, we used MODIS ocean color satellite data at ( 250 m spatial resolution ) with appropriate atmospheric correction (AC), and cloud masking parameters. Results confirmed that standard MODIS data products are not accurate since they are designed for open ocean waters. First, the MUMM AC showed to be suitable while near-infrared/shortwave-infrared (NIR/SWIR) switching AC failed to retrieve reflectance values even in the less turbid areas. Second, MODIS default cloud masking failed to delineate cloud edges thereby contaminating the data. SWIR cloud masking, however, masked cloud artifacts effectively. Third, with the selected AC and cloud masking parameters, NASA’s default Chl-a algorithm (OC X ) underestimated the values with high retrieval errors (RMSE = 10.2 mg.m -3 ). The GSM algorithm-derived Chl-a proved to be more appropriate (RMSE= 4.5 mg.m -3 ). We applied the appropriate processing schemes to understand the spatial and temporal variations of WQ indicators. The scheme was able to show the increase of Chl-a and SPM as affected by the increased rainfall and river flow. This study demonstrated the potential of MODIS in coastal monitoring of the area and the applicability of the decades of archived data in its management.

Wyndel Sanoza, University of the Philippines Cebu, [email protected], 0000-0002-4403-147X

David Doxaran, LOV Villefranche, CNRS/SU, [email protected]