| Full text | |
| Author(s): |
de Sousa, L. F. M. Faria
;
de Carvalho, L. A. Sander
;
Cirano, M.
;
Barberini, F. D. T.
;
Maciel, D. A.
;
Lange, P. K.
;
Soares, F. S.
;
Ciotti, A. M.
Total Authors: 8
|
| Document type: | Journal article |
| Source: | REGIONAL STUDIES IN MARINE SCIENCE; v. 90, p. 15-pg., 2025-12-15. |
| Abstract | |
The Guanabara Bay (GB) faces significant water quality degradation due to natural and human-induced pressures. The role of meteorological, oceanographic and hydrological variables and how they relate to water color still require further investigation in order to understand their environmental impact. This study investigates the spatio-temporal dynamics of turbidity in GB as an indicator of suspended material. Using a 20-year MODIS-Terra dataset, we applied a robust methodology for sunglint and skyglint correction to develop a turbidity estimation algorithm, alongside testing semi-analytical methods. We analyzed images based on their median and standard deviation across wet (November-March) and dry (April-October) periods, considering both flood and ebb tides during spring, transition, and neap tidal conditions. The second-order polynomial regression algorithm revealed to be not only effective but also the one with easier applicability for turbidity estimation using the red band (645 nm) in Google Earth Engine platform. The spatial-temporal evaluation showed higher turbidity and variability in the northeast and northwest regions, associated with major river inputs, while the lowest turbidity occurred near the bay's entrance, linked to continuous water renewal from the Atlantic Ocean. Increased variability at the bay's entrance during the wet season might be related to the intensification of upwelling waters during the flood tide. Turbidity is typically higher during ebb tides when compared to flood tides, with spring tides showing higher values than neap tides. Nevertheless, more research is necessary to understand turbidity variations with tides and the role of residual currents and wind-driven sediment resuspension. (AU) | |
| FAPESP's process: | 23/13904-7 - Leveraging eutrophication monitoring in São Paulo state coastal and inland waters via satellite multi-spectral data |
| Grantee: | Daniel Andrade Maciel |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 21/13367-6 - The influence of changes in vertical optical properties in coastal waters of the State of São Paulo on hyperspectral remote sensing signals |
| Grantee: | Aurea Maria Ciotti |
| Support Opportunities: | BIOTA-FAPESP Program - Regular Research Grants |