**3.3 Modeling of chlorophyll-A concentration**

Bio-optical algorithms OC2 and OC3 were used to extract chlorophyll-A concentration from Landsat-8 data. This bio-optical model is based on nonlinear relationships between ocean reflection reflectance and field data that actually link optical measurements of reflection to qualitative parameters such as chlorophyll concentration and range-of-coastal, blue, and green weather to estimate chlorophyll concentration. Uses the following equations to calculate.

> ( 01 2233) 10 + ∗+ ∗ + ∗ = *a a Ra R a R C R Rrs Blue Rrs Green* = log / ( ) (2) ( 01 2233) 10 + ∗+ ∗ + ∗ = *a a Ra R a R C R Rrs Rrs* = log 490 / 555 ( ) (3)

Where **a** are coefficients that are estimated and modeled through the relationship between field data and remote sensing. **Rrs** is a measure of distance at blue and green wavelengths, **R** is the band ratio and **C** is the concentration of chlorophyll-A in milligrams per cubic meter.
