Publications

Minu, P; Lotliker, AA; Shaju, SS; Ashraf, PM; Kumar, TS; Meenakumari, B (2016). Performance of operational satellite bio-optical algorithms in different water types in the southeastern Arabian Sea. OCEANOLOGIA, 58(4), 317-326.

Abstract
The in situ remote sensing reflectance (R-rs) and optically active substances (OAS) measured using hyperspectral radiometer, were used for optical classification of coastal waters in the southeastern Arabian Sea. The spectral R-rs showed three distinct water types, that were associated with the variability in OAS such as chlorophyll-a (chl-a), chromophoric dissolved organic matter (CDOM) and volume scattering function at 650 nm (beta(650)). The water types were classified as Type-I, Type-II and Type-III respectively for the three R-rs spectra. The Type-I waters showed the peak R-rs in the blue band (470 nm), whereas in the case of Type-II and III waters the peak R-rs was at 560 and 570 nm respectively. The shifting of the peak R-rs at the longer wavelength was due to an increase in concentration of OAS. Further, we evaluated six bio-optical algorithms (OC3C, OC4O, OC4, OC4E, OC3M and OC4O2) used operationally to retrieve chl-a from Coastal Zone Colour Scanner (CZCS), Ocean Colour Temperature Scanner (OCTS), Sea-viewing Wide Field-of- view Sensor (SeaWiFS), MEdium Resolution Imaging Spectrometer (MERIS), Moderate Resolution Imaging Spectroradiometer (MODIS) and Ocean Colour Monitor (OCM2). For chl-a concentration greater than 1.0 mg m(-3), algorithms based on the reference band ratios 488/510/520 nm to 547/550/555/560/565 nm have to be considered. The assessment of algorithms showed better performance of OC3M and OC4. All the algorithms exhibited better performance in Type-I waters. However, the performance was poor in Type-II and Type-III waters which could be attributed to the significant co-variance of chl-a with CDOM. (C) 2016 Institute of Oceanology of the Polish Academy of Sciences. Production and hosting by Elsevier Sp. z o.o.

DOI:
10.1016/j.oceano.2016.05.005

ISSN:
0078-3234