HYDROPT: A fast and flexible method to retrieve chlorophyll-a from multispectral satellite observations of optically complex coastal waters

Woerd, H.J. van der; Pasterkamp, R.

doi:10.1016/j.rse.2007.09.001

Cited by 87 publications

(49 citation statements)

References 48 publications

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“…Errors in satellite Chl-a algorithm retrievals in Case II waters (e.g., MODIS-OC3; OC4 for SeaWIFS; O'Reilly et al, 1998) do not provide accurate Chl-a estimates in coastal environments (e.g., Gitelson et al, 2007) and hamper our understanding of the dynamics of bio-optical properties (e.g., Van Der Woerd & Pasterkamp, 2008;Ruddick et al, 2014). To improve the noise:error ratios associated with Chl-a retrievals, a new satellite product was developed following the SeaWiFS mission to better understand space-time patterns of Chl-a biomass and other phytoplankton properties.…”

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confidence: 99%

First assessment of MODIS satellite ocean color products (OC3 and nFLH) in the Inner Sea of Chiloe, northern Patagonia

Lara

Saldías

Westberry

et al. 2017

lajar

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ABSTRACT. The use of remote sensing has allowed enormous progress in our understanding of biophysical processes worldwide. Despite their importance, the use of satellite bio-optical products is still limited due to optical complexity. In this study we assess the performance of the Moderate Resolution Imaging Spectroradiometer algorithm for chlorophyll-a (MODIS-OC3) and of normalized Fluorescence Line Height (nFLH), in inner waters of northern Chilean Patagonia (41°-45ºS). Satellite data were evaluated using a compilation of in situ chlorophyll-a data collected by the CIMAR-FIORDOS program during 2003-2012. During austral spring MODIS-OC3 showed a significant relationship with in situ measurements (R 2 = 0.2, P = 0.03, F = 5.33) in comparison with winter when the relationship was non-significant. In contrast, nFLH explained a significant fraction of observed variance of Chl-a during austral winter (R 2 = 0.54, P = <0.01, F = 10.68) and this relationship was not significant in spring. Our preliminary results offer an excellent chance to understand patterns of variability of the autotrophic biomass and physiological status in optically complex interior marine ecosystems.

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confidence: 99%

First assessment of MODIS satellite ocean color products (OC3 and nFLH) in the Inner Sea of Chiloe, northern Patagonia

Lara

Saldías

Westberry

et al. 2017

lajar

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“…The standard products of ocean colour instruments are based on the calculated water leaving radiance or remote sensing reflectance (R rs ) and the derived inherent optical properties of water (IOP) that describe the attenuation by absorption (a), scattering (b), and total attenuation (c = a + b m −1 ) at each wavelength (λ). These quantities that describe the incoming and outgoing light field are combined in simple blue-green ratio or more complex semi-empirical algorithms to estimate the substance composition in water (Chl a), suspended particulate material (SPM), and coloured dissolved organic matter (CDOM)) [33][34][35][36]. A very short resume of products involved is given in the last column of Table 2.…”

Section: Quality Control and Compatability To Common Coast And Ocean mentioning

confidence: 99%

Citizen Bio-Optical Observations from Coast- and Ocean and Their Compatibility with Ocean Colour Satellite Measurements

Busch

Bardají

Ceccaroni³

et al. 2016

Remote Sensing

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Marine processes are observed with sensors from both the ground and space over large spatio-temporal scales. Citizen-based contributions can fill observational gaps and increase environmental stewardship amongst the public. For this purpose, tools and methods for citizen science need to (1) complement existing datasets; and (2) be affordable, while appealing to different user and developer groups. In this article, tools and methods developed in the 7th Framework Programme of European Union (EU FP 7) funded project Citclops (citizens' observatories for coast and ocean optical monitoring) are reviewed. Tools range from a stand-alone smartphone app to devices with Arduino and 3-D printing, and hence are attractive to a diversity of users; from the general public to more specified maker-and open labware movements. Standardization to common water quality parameters and methods allows long-term storage in regular marine data repositories, such as SeaDataNet and EMODnet, thereby providing open data access. Due to the given intercomparability to existing remote sensing datasets, these tools are ready to complement the marine datapool. In the future, such combined satellite and citizen observations may set measurements by the engaged public in a larger context and hence increase their individual meaning. In a wider sense, a synoptic use can support research, management authorities, and societies at large.

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“…More recent efforts have concentrated on a variety of non-linear optimization algorithms (for a review see [26]). Despite this switch to more advanced optimization methods, many authors still use simple error, or objective functions based on the sum of squared error (SSE) or mean squared error (MSE) to measure the disparity between measured and modeled r rs during optimization [2,3,25,26,36,37]:…”

Section: Inversion Of Reflectancementioning

confidence: 99%

Optimization of a Semi-Analytical Algorithm for Multi-Temporal Water Quality Monitoring in Inland Waters with Wide Natural Variability

Bramante

Sin

2015

Remote Sensing

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Current spectrometer design and the increasingly affordable price of field hyperspectral sensors are making feasible their use for water quality monitoring. In this study, we parameterized a semi-analytical algorithm to derive constituent concentrations from field spectroradiometer measurements in ten freshwater reservoirs over two years. In contrast to algorithms parameterized for single airborne or satellite sensor deployments, we optimized the algorithm for robust performance across all reservoirs and for multi-temporal application. Our algorithm produced chlorophyll-a concentration estimates with a root mean squared error (RMSE) of 7.7 mg¤m ¡3 over a range of 4-135 mg¤m ¡3 . The model also produced estimates of total suspended solids (TSS) concentration with an RMSE of 4.0 g¤m ¡3 over a range of 0-25 g¤m ¡3 . Choosing a non-linear objective function during inversion reduced variance of residuals in chlorophyll-a and TSS estimates by 20 and 18 percentage points, respectively. Application of our algorithm to two years of data and over ten study sites allowed us to specify sources of suboptimal parameterization and measure the non-stationarity of algorithm performance, analyses difficult for short or single deployments. Suboptimal parameterization, especially of backscatter properties between reservoirs, was the greatest source of error in our algorithm, accounting for 17%-20% of all error. In only one reservoir was time-dependent error apparent. In this reservoir, decreases in TSS over time resulted in less TSS estimate error due to imperfect model parameterization. For future applications, especially with ground-based sensors, model performance can easily be improved by using non-linear inversion procedures and replicating spectral measurements.

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HYDROPT: A fast and flexible method to retrieve chlorophyll-a from multispectral satellite observations of optically complex coastal waters

Cited by 87 publications

References 48 publications

First assessment of MODIS satellite ocean color products (OC3 and nFLH) in the Inner Sea of Chiloe, northern Patagonia

First assessment of MODIS satellite ocean color products (OC3 and nFLH) in the Inner Sea of Chiloe, northern Patagonia

Citizen Bio-Optical Observations from Coast- and Ocean and Their Compatibility with Ocean Colour Satellite Measurements

Optimization of a Semi-Analytical Algorithm for Multi-Temporal Water Quality Monitoring in Inland Waters with Wide Natural Variability

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