Abstract:
This study focuses on the variability and relationships of bio-optical properties
with optically active constituents in the southern South China Sea. On these
bases, the applicability and the limits of reliability of satellite ocean colour
algorithm in this study area were also assessed. To achieve this goal, two
study areas with distinct bio-optical conditions: Brunei Bay (BB) coastal water
which characterized by high riverine discharge, strong phytoplankton blooms
and suspended particles, and east coast of peninsular Malaysia (ECPM) water
with relatively low chlorophyll and suspended particle concentrations; were
intensively investigated. In both study areas, in-situ measurements of
underwater radiation fields, in-water constituents and absorption properties
were conducted during bio-optical cruises in January and May 2014. The
analyses of data revealed a significant variation in bio-optical properties
between BB and ECPM waters. High concentrations in both constituents and
optical properties were observed in BB while ECPM is characterized by
relatively low concentration of constituents and weak optical signals.
Differences in bio-optical properties between both study areas are clearly
showed by variation in phytoplankton specific absorption coefficients; very
high values for low chlorophyll in ECPM and low values for relatively high
chlorophyll in BB, an indicator of strong package effect. In both areas, the
result found that coloured dissolved organic matter (CDOM) is the most
dominant absorber, contributing about 65% in ECPM and 77% in BB, and this
suggests the significant important of CDOM in determining the reflectance
signal in this study area. Due to very high concentrations of non-pigmented
particles in BB, the shape and magnitude of absorption properties and
reflectance signal are found to be significantly different as compared to results
observed in ECPM.
