Quantifying Harmful Algal Blooms Using Satellite Remote Sensing: A Case Study at Lake Erie
Tseng, Kuo-Hsin1; Jiyoung, Lee2; Zhang, Feng2; Lee, Cheonghoon2; Hu, Chenlin2; Shum, C.K.2
1The Ohio State Univerisy, UNITED STATES; 2The Ohio State University, UNITED STATES
Harmful Algal blooms (HABs) and their toxins are significant health risks in moderate to severe eutrophic lakes. Among a variety of cyanobacteria, Microcystis aeruginosa is the dominant species in Great Lakes (U.S.), Taihu (China) and many other lakes worldwide. Measuring phycocyanin concentrations (PC) in the toxic M. aeruginosa is a viable technique from remote sensing and multispectral analysis. In this study, we demonstrate an observation of temporal/spatial HABs dynamic using satellite remote sensing that calibrated with in situ PC measurements in Lake Erie. By using the MEdium Resolution Imaging Spectrometer (MERIS) water color optical instrument onboard of European Space Agency (ESA)'s Envisat (Environmental Satellite), which has a 3-day global coverage and a spatial resolution up to ~300 m, we are able to detect the anomaly of HABs in water bodies via PC quantification (MERIS vs. in situ, r=0.84 and bias=0.04 mg m-3). The successful experiment conducted within 1 km offshore region provides an important calibration between spaceborne observation and ground truth, which implies this technique may be applicable to other smaller freshwaters. It is expected a similar algorithm can be applied and improved for the Ocean Land Colour Instrument (OLCI) onboard ESA's Sentinel-3 during Cal/Val phase. Furthermore, a retrospective analysis incorporating PC and Chlorophyll-a from Envisat, water surface temperature from the Moderate Resolution Imaging Spectroradiometer (MODIS) radiometry, and atmospheric variables (i.e., air temperature, precipitation, and wind/wave components) from ECMWF's ERA-Interim reanalysis is proposed to study the retention/bloom process towards predictive modeling efforts.