Publications

Silva, GSD; Garcia, CAE (2021). Evaluation of ocean chlorophyll-a remote sensing algorithms using in situ fluorescence data in Southern Brazilian Coastal Waters. OCEAN AND COASTAL RESEARCH, 69, e21012.

Abstract
A performance evaluation of ocean color chlorophyll-a algorithms was conducted based on the in situ fluorescence chlorophyll concentration (F-chl) measured by a sensor on the buoy SiMCosta-SC01 in coastal waters of South Brazil. The operational algorithms are used in MODIS and VIIRS sensors to derive satellite chlorophyll concentration (C-sat). F-chl values were successfully corrected for nonphotochemical quenching (NPQ) by an interpolation of sunrise and sunset daily measurements. A laboratory-derived calibration coefficient was applied to convert the unquenching F-chl values into chlorophyll concentration (C-flu). Overall, linear regression analysis between C-flu and C-sat for both sensors showed good results, with the coefficient of determination (R-2) varying between 0.88 and 0.96, slopes between 0.92 and 1.02 and intercepts between -0.17 and 0.13. The MODIS algorithm (R-2 = 0.96, slope = 1.02, RMSE = 0.16 mg m(-3), BIAS = 0.16 mg m(-3), for N = 222 and time interval +/- 1 h) presented slightly better performance than VIIRS (R-2 = 0.92, slope = 0.96, RMSE = 0.25 mg m-3, BIAS = -0.25 mg m(-3), for N = 284 and time interval +/- 1 h). These results represent the most comprehensive satellite data analysis for this region, suggesting that the approach may be applicable to other SiMCosta buoys.

DOI:
10.1590/2675-2824069.20-014gsdms

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