Evaluation of Multi temporal MODIS Data for Monitoring of Red Tide Bloom in Persian Gulf, South of Iran

Harmful Algal Bloom (HABs) has caused a massive fish kill and discoloration in Persian Gulf from September 2008 to February 2009. Timely detection of HABs is critical for assessment, monitoring and management of red tide impacts. Remotely sensed data provide very valuable capabilities for this task. For practical examination of these capabilities, multi temporal data of MODIS with spatial resolution of 1 KM acquired from September 2008 to February 2009 has been used. Fluoresce line Height FLH (Wm-2µm-1Sr-1) has been computed for all data sets. The FLH data have been ordinarily classified. The resulting classified data have been compared with field measurements of the red tide. Considerable agreements between the FLH classes and filed data of red tide concentrations has been observed. In contrast, to FLH data, chlorophyll data provided by the traditionally used band-ratio, lead to false information about the presence of red tide. Comparison of the time series of MODIS image for the period of six months from September 2008 to February 2009 has shown that, the intensity of blood has increased in February. Also, in September 2008, blood has started from west and has expanded to eastern parts of the Persian Gulf. Comparison of the sea surface temperature (SST) data with those of the FLH, has shown that red tide tend to bloom in relatively cooler waters (18-20 ◦c). Although, it does not mean that cooler waters are a good indicator of the presence of a red tide in Persian Gulf. The main conclusion of research is that MODIS FLH data provides very valuable information for observation and monitoring of the red tide.