Mapping lake CDOM by satellite remote sensing

Mapping macroalgal blooms in the Yellow Sea and East China Sea using HJ-1 and Landsat data: Application of a virtual baseline reflectance height technique

“…The ENVI™ FLAASH (Fast Line of sight Atmospheric Analysis of Spectral Hypercubes) atmospheric correction module was applied to Landsat and HJ-1 images to derive the sea surface reflectance (R, unitless). FLAASH includes a method for aerosol estimation based on the dark pixel reflectance ratio method (Kaufman, Wald, Remer, Gao, Li, & Flynn, 1997), which has been successfully used in the atmospheric correction of multi-band or hyperspectral images over waters (e.g., Kutser, Pierson, Kallio, Reinart, & Sobek, 2004;Kutser, 2012;Tian, Lu, Chen, Yu, Xiao, Qiu, & Zhao, 2010;Moses, Gitelson, Perk, Gurlin, Rundquist, Leavitt, Barrow, & Brakhage, 2012;Zeng, Zhao, Tian, & Chen, 2013). The requirement of absolute accuracy of atmospheric correction in this study, however, is not critical because it is the relative height of the near-infrared band that is used for detecting and quantifying macroalgae.…”

Empirical estimation of total phosphorus concentration in the mainstream of the Qiantang River in China using Landsat TM data

“…Atmospheric correction of satellite imagery is very important in aquatic remote sensing, as a considerable amount (. 90% in many cases) of radiation detected by satellite sensors is backscattered from the atmosphere without ever penetrating the water (Kutser et al 2005). For multiple scenes of different dates, it is especially important to normalize atmospheric effects.…”

Optical remote sensing of lakes: an overview on Lake Maggiore

“…The spectrum taken near the tributary of Lake Vänern (Sweden) (Fig. 1e) is typical of those taken in CDOM-rich waters where CDOM absorption lowers reflectance at short wavelengths (Kutser et al, 2005;Koponen et al, 2007), Finally, Lake Neusiedl (Austria, Hungary) ( Fig. 1f), characterised by very turbid waters (SPM=100 gm -3 ), hence producing an high backscattering of downwelling light, hence generating high water reflectance (Bukata et al, 1995).…”

“…The parameters which can be directly quantified using remote sensing techniques are the following: -suspended particulate matter (SPM), which is placed in suspension by wind-wave stirring of shallow waters and can be a tracer for inflowing pollutants (Eleveld, 2012); -phytoplankton and cyanobacteria pigments mainly as chlorophyll-a (chl-a) or phycocyanin (PC), that can be used to indicate the trophic level, to evaluate the presence of potentially toxic algal blooms and as a proxy of phytoplankton biomass (Randolf et al, 2008;Ruiz-Verdù et al, 2008); -coloured DOM (CDOM), commonly called yellow substances, whose might indicate the presence of either fulvic or humic acids; CDOM is also investigated because of its role in protecting aquatic biota from ultraviolet solar radiation and its influence on specifically heterotrophic bacterial productivity in the water column, indicative of the shift from net autotrophy to net heterotrophy (Kutser et al, 2005); -the spectral attenuation coefficient (Kd), which is theoretically inversely related to the depth of the photic zone (Kratzer et al, 2003;Pierson et al, 2008). Usually, the assessment of the water optically active parameters relies on the knowledge of the behaviour of light in waters as affected by these light-attenuating constituents.…”