Comparison of the efficacy of MODIS and MERIS data for detecting cyanobacterial blooms in the southern Caspian Sea

摘要

Medium Resolution Imaging Spectrometer (MERIS) data, Moderate Resolution Imaging Spectroradiome-ter (MODIS) data, and hydro-biological measurements were used to detect two very severe blooms in the southern Caspian Sea in 2005 and 2010. The MERIS Cyanobacteria Index (CI_(MERIS)) was more reliable for detecting cyanobacterial blooms. The CI_(MERIS) and MODIS cyanobacteria indices (CI_(MODIS)) were compared in an effort to find a reliable method for detecting future blooms, as MERIS data were not available after April 2012. The CI_(MODIS) had a linear relationship with and similar spatial patterns to the CI_(MERIS). On the CI_(MODIS) images, extremely high biomass cyanobacteria patches were masked. A comparison of classified in situ data with the CI_(MODIS) and Floating Algal Index (FAI) from four images of a severe bloom event in 2005 showed that the FAI is a reliable index for bloom detection over extremely dense patches. The corrected CI_(MODIS), the MODIS FAI and in situ data are adequate tools for cyanobacterial bloom monitoring in the southern Caspian Sea.