Identifying Suspended Particulate Matters in an Urban
Coastal System: Significance and Application of Particle
Size Analysis |
Jong Ho Ahn† |
Division of Water and Environment, Korea Environment Institute, Seoul 122-706, Korea |
Corresponding Author:
Jong Ho Ahn ,Tel: +82-2-380-7741, Fax: +82-2-380-7644, Email: ahnjh@kei.re.kr |
Received: January 21, 2012; Accepted: August 20, 2012. |
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ABSTRACT |
In situ particle size spectra are obtained from two sequent cruises in order to evaluate the physical consequences of suspended particulate
matters caused by episodic storm runoff from the Santa Ana River watershed, an urbanized coastal watershed. Suspended particles
from various sources including surface runoff, near-bed resuspension, and phytoplankton are identified in empirical orthogonal
function (EOF) analysis and an entropy-based parameterization (Shannon entropy). The first EOF mode is associated with high turbidity
and fine particles as indicated by the elevated beam attenuation near the Santa Ana River and Newport Bay outlets, and the second
EOF mode explains the suspended sediment dispersal and particle coarsening at the near-surface plume. Chlorophyll particles are also
distinguished by negative magnitudes of the first EOF mode, which is supported by the relationship between fluorescence and beam
attenuation. The integrated observation between the first EOF mode and the Shannon entropy index accentuates the characteristics of
two different structures and/or sources of sediment particles; the near-surface plumes are originated from runoff water outflow, while
the near-bottom particles are resuspended due to increased wave heights or mobilizing bottom turbidity currents. In a coastal pollution
context, these methods may offer useful means of characterizing particle-associated pollutants for purposes of source tracking and
environmental interpretation. |
Keywords:
Empirical orthogonal function | Particle size spectra | Shannon entropy | Storm runoff water | Suspended particulate matter |
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