<Emphasis Type="Italic">Cochlodinium polykrikoides</Emphasis> red tide detection in the South Sea of Korea using spectral classification of MODIS data |
| |
| Authors: | Young Baek Son Joji Ishizaka Jong-Chul Jeong Hyun-Choel Kim Taehee Lee |
| |
| Institution: | 1.Korea Ocean Satellite Center (KOSC),KORDI,Seoul,Korea;2.Hydrospheric Atmospheric Research Center (HyARC),Nagoya University,Aichi,Japan;3.Department of Geoinformatics Engineering,Namseoul University,Cheonan,Korea;4.Korea Polar Research Institute,KORDI,Incheon,Korea;5.South Sea Environment Research Department, South Sea Branch,KORDI,Geoje,Korea |
| |
| Abstract: | To distinguish true red tide water (particularly Cochlodinium polykrikoides blooms) from non-red tide water (false satellite high chlorophyll water) in the South Sea of Korea, we developed a systematic
classification method using spectral information from MODIS level products and applied it to five different harmful algal
bloom events. Red tide and nonred tide waters were classified based on four different criteria. The first step revealed that
the radiance peaks of potential red tide water occurred at 555 and 678 nm. The second step separated optically different waters
that were influenced by relatively low and high contributions of colored dissolved organic matter (CDOM) (including detritus)
to chlorophyll. The third and fourth steps discriminated red tide water from non-red tide water based on the blue-to-green
ratio in areas with lower and higher contributions of CDOM to chlorophyll, respectively. After applying the red tide classification
(using the four criteria), the spectral response of the red tide water, which is influenced by pigment concentration, showed
different slopes for the blue and green bands (lower slope at blue bands and higher slope at green bands). The opposite result
was found for non-red tide water, due to decreasing phytoplankton absorption and increasing detritus/CDOM absorption at blue
bands. The results were well matched with the discoloration of water (blue to dark red/brown) and delineated the areal coverage
of C. polykrikoides blooms, revealing the nature of spatial and temporal variations in red tides. This simple spectral classification method
led to increase user accuracy for C. polykrikoides and non-red tide blooms (>46% and >97%) and provided a more reliable and robust identification of red tides over a wide range
of oceanic environments than was possible using chlorophyll a concentration, chlorophyll anomaly, fluorescence analysis, or proposed red tide detection algorithms. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
