Data processing and interpretation of sea radiance factor measurements

Arst, Helgi; Kutser, T.

doi:10.1111/j.1751-8369.1994.tb00432.x

Cited by 15 publications

(3 citation statements)

References 11 publications

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“…For example, single band algorithms, band ratios, more sophisticated colour indices or analytical methods for retrieving three or more water properties simultaneously have been used [29][30][31][32][33]. We chose to use peak height algorithms as the measured reflectance had only two peaks and very low signal at other wavelengths.…”

Section: Remote Sensing Algorithmsmentioning

confidence: 99%

Remote Sensing of Black Lakes and Using 810 nm Reflectance Peak for Retrieving Water Quality Parameters of Optically Complex Waters

et al. 2016

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Many lakes in boreal and arctic regions have high concentrations of CDOM (coloured dissolved organic matter). Remote sensing of such lakes is complicated due to very low water leaving signals. There are extreme (black) lakes where the water reflectance values are negligible in almost entire visible part of spectrum (400-700 nm) due to the absorption by CDOM. In these lakes, the only water-leaving signal detectable by remote sensing sensors occurs as two peaks-near 710 nm and 810 nm. The first peak has been widely used in remote sensing of eutrophic waters for more than two decades. We show on the example of field radiometry data collected in Estonian and Swedish lakes that the height of the 810 nm peak can also be used in retrieving water constituents from remote sensing data. This is important especially in black lakes where the height of the 710 nm peak is still affected by CDOM. We have shown that the 810 nm peak can be used also in remote sensing of a wide variety of lakes. The 810 nm peak is caused by combined effect of slight decrease in absorption by water molecules and backscattering from particulate material in the water. Phytoplankton was the dominant particulate material in most of the studied lakes. Therefore, the height of the 810 peak was in good correlation with all proxies of phytoplankton biomass-chlorophyll-a (R 2 = 0.77), total suspended matter (R 2 = 0.70), and suspended particulate organic matter (R 2 = 0.68). There was no correlation between the peak height and the suspended particulate inorganic matter. Satellite sensors with sufficient spatial and radiometric resolution for mapping lake water quality (Landsat 8 OLI and Sentinel-2 MSI) were launched recently. In order to test whether these satellites can capture the 810 nm peak we simulated the spectral performance of these two satellites from field radiometry data. Actual satellite imagery from a black lake was also used to study whether these sensors can detect the peak despite their band configuration. Sentinel 2 MSI has a nearly perfectly positioned band at 705 nm to characterize the 700-720 nm peak. We found that the MSI 783 nm band can be used to detect the 810 nm peak despite the location of this band is not in perfect to capture the peak.

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Section: Remote Sensing Algorithmsmentioning

confidence: 99%

Remote Sensing of Black Lakes and Using 810 nm Reflectance Peak for Retrieving Water Quality Parameters of Optically Complex Waters

et al. 2016

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“…Different remote sensing products (chlorophyll a, CDOM, suspended matter, diffuse attenuation coefficient, etc.) have been developed or adopted for the Baltic Sea [3,4,6,8,11,[17][18][19][20][21][22][23][24][25][26][27][28]. Many of the recent studies rely on MERIS data and the results can probably be implemented on Sentinel-3 OLCI data as well.…”

Section: Introductionmentioning

confidence: 99%

Mapping Water Quality Parameters with Sentinel-3 Ocean and Land Colour Instrument imagery in the Baltic Sea

et al. 2017

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Abstract:The launch of Ocean and Land Colour Instrument (OLCI) on board Sentinel-3A in 2016 is the beginning of a new era in long time, continuous, high frequency water quality monitoring of coastal waters. Therefore, there is a strong need to validate the OLCI products to be sure that the technical capabilities provided will be used in the best possible way in water quality monitoring and research. The Baltic Sea is an optically complex waterbody where many ocean colour products, performing well in other waterbodies, fail. We tested the performance of standard Case-2 Regional/Coast Colour (C2RCC) processing chain in retrieving water reflectance, inherent optical properties (IOPs), and water quality parameters such as chlorophyll a, total suspended matter (TSM) and coloured dissolved organic matter (CDOM) in the Baltic Sea. The reflectance spectra produced by the C2RCC are realistic in both shape and magnitude. However, the IOPs, and consequently the water quality parameters estimated by the C2RCC, did not have correlation with in situ data. On the other hand, some tested empirical remote sensing algorithms performed well in retrieving chlorophyll a, TSM, CDOM and Secchi depth from the reflectance produced by the C2RCC. This suggests that the atmospheric correction part of the processor performs relatively well while IOP retrieval part of the neural network needs extensive training with actual IOP data before it can produce reasonable estimates for the Baltic Sea.

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“…Knowledge of phytoplankton absorption and its dependence on the concentration of chlorophyll-a as well as accessory pigments is fundamental in the refinement of bio-optical models (Arst and Kutser, 1994;Garver and Siegel, 1997;Kutser et al, 2001;Lee and Carder, 2004;Smyth et al, 2006;Pan et al, 2008;Binding et al, 2012). The bio-optical models are used in studying underwater light field but are primarily used in interpretation of remote sensing data.…”

Section: Introductionmentioning

confidence: 99%

Parameterization of chlorophyll-specific phytoplankton absorption coefficients for productive lake waters

et al. 2016

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Data processing and interpretation of sea radiance factor measurements

Cited by 15 publications

References 11 publications

Remote Sensing of Black Lakes and Using 810 nm Reflectance Peak for Retrieving Water Quality Parameters of Optically Complex Waters

Remote Sensing of Black Lakes and Using 810 nm Reflectance Peak for Retrieving Water Quality Parameters of Optically Complex Waters

Mapping Water Quality Parameters with Sentinel-3 Ocean and Land Colour Instrument imagery in the Baltic Sea

Parameterization of chlorophyll-specific phytoplankton absorption coefficients for productive lake waters

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