Prof. Samir Ahmed Profile

Prof. Samir Ahmed

Herbert Kayser Professor at City College of New York

SPIE Involvement:

Conference Program Committee | Author

Publications (115)

Proceedings Article | 13 May 2020 Paper

Blue band reflectance uncertainties in coastal waters and their impact on retrieval algorithms

Alex Gilerson, Eder Herrera Estrella, Philipp Grotsch, Mateusz Malinowski, Sam Ahmed

Proceedings Volume 11420, 1142006 (2020) https://doi.org/10.1117/12.2559895

KEYWORDS: Satellites, Reflectivity, Water, Sensors, Remote sensing, Spatial resolution, Ocean optics, MODIS, Aerosols, Earth observing sensors

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Proceedings Article | 18 October 2019 Presentation

Satellite neural network ocean color retrievals of harmful algal blooms highlight advantages of avoiding deep blue bands (Conference Presentation)

Ahmed El-Habashi, Samir Ahmed, Claudia Duran, Alex Gilerson, Vincent Lovko, Michael Ondrusek, Stefanos Spiratos

Proceedings Volume 11150, 1115003 (2019) https://doi.org/10.1117/12.2531860

KEYWORDS: Satellites, In situ metrology, Neural networks, Atmospheric corrections, Optical simulations, Optical properties, Visible radiation, Infrared imaging, Radiometry, Remote sensing

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Our previous work showed the efficacy neural network (NN) approaches for satellite detection of Karenia brevis (KB) harmful algal blooms (HABs) in the West Florida Shelf (WFS). Applying a multiband NN, trained on a wide range of synthetically simulated inherent optical properties (IOPs), the NN takes Visible Infrared Imaging Radiometer Suite (VIIRS) remote sensing reflectance (Rrs) measurements at 486, 551 and 671 nm bands as inputs and produces related IOPs at 443 nm, including the absorption coefficient of phytoplankton, (aph443) as retrieved output images. We convert the retrieved aph443 values into equivalent chlorophyll-a [Chla] and KB HAB concentration mages, using known empirical relationships. We then compared VIIRS NN retrievals of KB HABs in the WFS with those obtained using other algorithms, and evaluated their accuracy against near co-incident in situ cell count measurements available over the 2012-16 period. Results highlighted the important impact of rapid (15-20 minutes) temporal variations on retrieval accuracy, and showed that the NN technique exhibited the highest accuracy statistics for retrievals of KB HABs in the WFS. This paper presents significant results in three areas. (i) We extend evaluations and comparisons of NN retrievals of aph443 and [Chla] with retrievals from other ocean color (OC) algorithms to waters beyond the WFS, including both complex coastal and open ocean waters, along Florida and Atlantic coasts, with a large dynamic range of chlorophyll-a values. We also now add in situ radiometric measurements to obtain Rrs inputs to retrieval algorithms. In contrast to satellite Rrs retrievals, these are invulnerable to atmospheric transmission correction errors. This permits comparison of in situ radiometric measurement-based retrievals with simultaneous co-located satellite retrievals and validation against in situ sample measurements. This allows us to isolate different factors affecting retrieval accuracy and evaluate the intrinsic merits of different algorithms unencumbered by inadequate/erroneous atmospheric transmission assumptions and/or satellite instrumental calibration limitations. Results obtained extend and demonstrate the efficacy of NN algorithms to widely varying waters beyond the WFS, (ii) Since it is conjectured that in satellite retrievals, it is the deep blue wavelengths that are more detrimentally affected by atmospheric correction inadequacies, we examined impacts on algorithm retrieval accuracy when deep blue wavelengths are used for retrieving Rrs values. Retrievals using NN and OCI/OCx algorithms were compared against in situ sample measurements, using in situ radiometric Rrs measurements and satellite Rrs retrievals as inputs, first at 443 nm (deep blue) and then at 486 nm (non-deep blue). The results unambiguously show that satellite retrieval accuracy, as well as intrinsic retrieval accuracy from in situ radiometric measurements are improved when deep blue wavelengths (443 nm) are avoided in favor of non-deep blue wavelengths (486 nm), raising issues of both atmospheric correction as well as possible underwater spectral interference in CDOM rich and complex waters. Thereby arguing for use of OC algorithms using the longer wavelengths. (iii) Finally, new quantitative analysis of temporal, intra pixel and sample depth variability highlights their important impact on retrieval accuracy.

Proceedings Article | 14 May 2019 Presentation

Chlorophyll retrieval accuracies from satellite and in-situ radiometric measurements in Open Ocean and complex and bloom waters (Conference Presentation)

Ahmed El-Habashi, Claudia Duran, Samir Ahmed, Vincent Lovko, Stefanos Spiratos

Proceedings Volume 11014, 110140D (2019) https://doi.org/10.1117/12.2521147

KEYWORDS: Satellites, Neural networks, Luminescence, MODIS, Remote sensing, Reflectivity, Absorption, Earth observing sensors, Atmospheric corrections

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SPIE Journal Paper | 2 May 2019 Open Access

Analyses of satellite ocean color retrievals show advantage of neural network approaches and algorithms that avoid deep blue bands

Ahmed El-Habashi, Sam Ahmed, Michael Ondrusek, Vincent Lovko

JARS, Vol. 13, Issue 02, 024509, (May 2019) https://doi.org/10.1117/12.10.1117/1.JRS.13.024509

KEYWORDS: Satellites, In situ metrology, Atmospheric corrections, Water, Algorithm development, In situ remote sensing, Satellite imaging, Earth observing sensors, Ocean optics, Error analysis

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Proceedings Article | 5 October 2018 Presentation + Paper

Evaluation and comparison of JPSS VIIRS neural network retrievals of harmful algal blooms with other retrieval algorithms, validated against in-situ radiometric and sample measurements in the West Florida Shelf, and examination of impacts of atmospheric corrections, temporal variations and complex in-shore waters

Michael Ondrusek, Sam Ahmed, Ahmed El-Habashi, Vincent Lovko

Proceedings Volume 10784, 1078402 (2018) https://doi.org/10.1117/12.2325749

KEYWORDS: Satellites, Water, Earth observing sensors, Atmospheric corrections, Absorption, Algorithm development, Neural networks, In situ metrology, Image retrieval, Backscatter

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Proceedings Article | 25 May 2018 Presentation + Paper

Comparison of aerosol models from the Ocean Color satellite sensors and AERONET-OC and their impact on reflectance spectra in coastal waters

Eder Herrera, Yaron Klein, Robert Foster, Barry Gross, Robert Arnone, Sam Ahmed, Alexander Gilerson

Proceedings Volume 10631, 1063106 (2018) https://doi.org/10.1117/12.2309581

KEYWORDS: Aerosols, Satellites, Sensors, Reflectivity, MODIS, Atmospheric modeling, Atmospheric corrections, Water, Remote sensing, Data modeling

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Proceedings Article | 15 May 2018 Presentation

Satellite monitoring and interpretation of dynamically changing concentrations of Karenia Brevis harmful algal blooms in the West Florida Shelf (Conference Presentation)

Samir Ahmed, Ahmed El-Habashi, Vincent Lovko

Proceedings Volume 10631, 106310D (2018) https://doi.org/10.1117/12.2304357

KEYWORDS: Satellites, Algorithm development, Evolutionary algorithms, MODIS, Neural networks, Atmospheric corrections, Earth observing sensors, Unmanned aerial vehicles

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Proceedings Article | 25 January 2018 Presentation

Impact on satellite retrievals of temporal changes in Karenia brevis harmful algal blooms in the West Florida Shelf (Conference Presentation)

Samir Ahmed, Ahmed El-Habashi, Vincent Lovko

Proceedings Volume 10422, 104220C (2018) https://doi.org/10.1117/12.2278612

KEYWORDS: Satellites, Neural networks, Optical properties, Remote sensing, Statistical analysis, Reflectivity, Absorption, Satellite imaging, Earth observing sensors, Backscatter

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We examine the impact of temporal changes on satellite retrievals of Karenia brevis Harmful Algal blooms (KB HABS) in the West Florida Shelf (WFS). These impacts are compared for retrievals from both VIIRS and MODIS-A using a number of retrieval techniques. The comparisons include our recently developed neural network (NN) technique. The neural network, previously developed by us, was trained on 10,000 data point part of a synthetic data of 20,000 inherent optical properties (IOPs) based on a wide range of IOP parameters for a large variety of natural conditions based on the NOMAD data. The NN then uses as inputs the remote sensing reflectance (Rrs) measurements at 486, 551 and 671 and 488, 555 and 667 nm which are available from VIIRS and MODIS-A respectively, to retrieve phytoplankton absorption at 443 nm in satellite images. This information, when combined with backscatter information has been shown by us to be effective for obtaining retrievals of KB HB HABs in the WFS. Other retrieval algorithms included in the present comparison are the blue/green OCI/OC3, the Generalized Inherent Optical Property (GIOP) model and the Quasi-Analytical Algorithm, (QAA version 5). The accuracies of VIIRS retrievals using all five techniques were then compared against all the in-situ measurements available over the 2012-2016 period for which concurrent or near concurrent match ups could be obtained with VIIRS retrievals. Analysis of retrieval statistics showed that the NN technique achieved the best accuracies. The analysis highlighted the impact of temporal variabilities on retrieval accuracies. The results showed the importance of having a shorter overlap time window between in-situ measurement and satellite retrieval. Retrievals where the maximum permissible overlap time window was shortened to 15 minutes, exhibited very significantly improved retrieval accuracies over those that were obtained with a 100 minute overlap time window, Retrievals that relaxed the overlap time window between in-situ measurement and satellite retrievals to simply the same day were hopelessly inaccurate by comparison. These results are believed to reflect the impact of temporal variabilities on retrieval accuracies. They underline the time limitations associated with satellite retrievals of inherently variable conditions and a changing scene. The temporal effects associated with KB HABs retrievals in the WFS were also examined by using images from consecutive VIIRS - MODIS-A – VIIRS overpasses overlapping the same parts of the WFS containing KB blooms. The consecutive images, all within an approximately 100 minute period, appear to confirm the changing bloom features. The temporal behavior of the KB blooms in the WFS over short time periods (less than100 minuntes) was further confirmed by a recent set of in-situ field measurements off the coast of Sarasota.

Proceedings Article | 3 October 2017 Paper

Characterization of aerosol parameters over ocean from the Ocean Color satellite sensors and AERONET-OC data

Barry Gross, Robert Arnone, Alex Gilerson, Eder Herrera, Yaron Klein, Robert Foster, Sam Ahmed

Proceedings Volume 10422, 104220H (2017) https://doi.org/10.1117/12.2279150

KEYWORDS: Aerosols, Atmospheric modeling, Satellites, Atmospheric corrections, Reflectivity, Sensors, Scattering, Atmospheric particles, Ocean optics, Data modeling

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Proceedings Article | 5 September 2017 Paper

Impact of fluorescence on the underwater polarized light field: comparison of theory and field measurements

Ahmed El-Habashi, Sam Ahmed, Carlos Carrizo, Robert Foster, Thomas Legbandt

Proceedings Volume 10402, 104022Q (2017) https://doi.org/10.1117/12.2279618

KEYWORDS: Luminescence, Polarization, Radiative transfer, Optical properties, Optical testing, Water, Polarimetry, Remote sensing, Ocean optics, Coastal modeling, Algorithm development

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Proceedings Article | 22 May 2017 Presentation + Paper

Neural network retrievals of phytoplankton absorption and Karenia brevis harmful algal blooms in the West Florida Shelf

Sam Ahmed, Ahmed El-Habashi, Vincent Lovko

Proceedings Volume 10186, 101860L (2017) https://doi.org/10.1117/12.2261848

KEYWORDS: Neural networks, Earth observing sensors, Satellites, Absorption

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Proceedings Article | 14 December 2016 Presentation

Neural network retrievals of Karenia brevis harmful algal blooms in the West Florida Shelf (Conference Presentation)

Samir Ahmed, Ahmed El-Habashi

Proceedings Volume 9999, 99990H (2016) https://doi.org/10.1117/12.2242079

KEYWORDS: Luminescence, Neural networks, Detection and tracking algorithms, Image retrieval, Satellites, Algorithm development, Backscatter, Image filtering, Image processing, Remote sensing

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Effective detection and tracking of Karenia brevis Harmful Algal Blooms (KB HAB) that frequently plague the coasts and beaches of the West Florida Shelf (WFS) is important because of their negative impacts on ecology. They pose threats to fisheries, human health, and directly affect tourism and local economies. Detection and tracking capabilities are needed for use with the Visible Infrared Imaging Radiometer Suite (VIIRS) satellite, so that HABs monitoring capabilities, which previously relied on imagery from the Moderate Resolution Imaging Spectroradiometer Aqua, can be extended to VIIRS. Unfortunately, VIIRS, unlike its predecessor MODIS-A, does not have a 678 nm channel to detect chlorophyll fluorescence, which is used in the normalized fluorescence height (nFLH) algorithm, or in the Red Band Difference (RBD) algorithm. Both these techniques have demonstrated that the remote sensing reflectance signal from the MODIS-A fluorescence band (Rrs 678 nm) helps in effectively detecting and tracking KB HABs in the WFS. To overcome the lack of a fluorescence channel on VIIRS, the approach described here, bypasses the need for measurements at 678nm, and permits extension of KB HABs satellite monitoring to VIIRS. The essence of the approach is the application of a standard multiband neural network (NN) inversion algorithm, previously developed and reported by us, that takes VIIRS Rrs measurements at the 486, 551 and 671nm bands as inputs, and produces as output the related Inherent Optical Properties (IOPs), namely: absorption coefficients of phytoplankton (aph443) dissolved organic matter (ag) and non-algal particulates (adm) as well as the particulate backscatter coefficient, (bbp) all at 443nm. We next need to relate aph443 in the VIIRS NN retrieved image to equivalent KB HABs concentrations. To do this, we apply additional constraints, defined by (i) low backscatter manifested as a maximum Rrs551 value and (ii) a minimum [Chla] threshold (and hence an equivalent minimum aph443min value) that are both known to be associated with KB HABs in the WFS. These two constraining filter processes are applied sequentially to the VIIRS NN retrieved aph443 image. First an image is made of retrieved VIIRS Rrs551. A mask is then made of all pixels with Rrs551≥ Rrs551max, the maximum value known to be compatible with the existence KB HABs. This is applied, as a filter to the VIIRS NN retrieved aph443 image to exclude pixels with Rrs551≥ Rrs551max. The residual image will then only show aph443 values that comply with Rrs551≤ Rrs551max. Then, in a second filter process, all values of aph443 ≤ aph443min are eliminated. The residual image will now only show aph443 values that are compatible with both criteria for KB HABs, and are therefore representative of KB HABs. It will be shown that when both these filter condition are applied to VIIRS NN aph443 retrievals, they can be used to effectively delineate and quantify KB HABs in the WFS. The KB HABs retrieved in this manner also show good correlations with in-situ KB HABs measurements as well as with nFLH retrievals and other techniques to which the same filtering criteria have been applied, confirming the viability of the approach.

Proceedings Article | 17 May 2016 Paper

Chlorophyll fluorescence and the polarized underwater light field: comparison of vector radiative transfer simulations and multi-angular hyperspectral polarization field measurements

Samir Ahmed, Ahmed El-habashi

Proceedings Volume 9827, 98270U (2016) https://doi.org/10.1117/12.2224284

KEYWORDS: Luminescence, Polarization, Radiative transfer, Hyperspectral simulation, Light scattering, Polarimetry, Particles, Scattering, Reflectivity, Absorption

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Proceedings Article | 4 May 2016 Paper

Retrieval of the polarized submarine light field from above surface measurements using polarimetric imaging

Sam Ahmed, Matteo Ottaviani, Robert Foster, Anna McGilloway, Alex Gilerson, Carlos Carrizo, Ahmed El-Habashi

Proceedings Volume 9853, 98530O (2016) https://doi.org/10.1117/12.2225111

KEYWORDS: Polarization, Remote sensing, Polarimetry, Cameras, Water, Radiative transfer, Radiometry, Polarizers, Calibration, Sensors

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Proceedings Article | 14 October 2015 Paper

Multi-band algorithms for the estimation of chlorophyll concentration in the Chesapeake Bay

Alexander Gilerson, Michael Ondrusek, Maria Tzortziou, Robert Foster, Ahmed El-Habashi, Sam Ahmed, Surya Prakash Tiwari

Proceedings Volume 9638, 96380A (2015) https://doi.org/10.1117/12.2195725

KEYWORDS: Satellites, Algorithm development, MODIS, Absorption, Sensors, Remote sensing, Satellite imaging, Reflectivity, Earth observing sensors, Particles

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Proceedings Article | 14 October 2015 Paper

Neural network algorithms for retrieval of harmful algal blooms in the west Florida shelf from VIIRS satellite observations and comparisons with other techniques, without the need for a fluorescence channel

A. El-habashi, S. Ahmed

Proceedings Volume 9638, 96380B (2015) https://doi.org/10.1117/12.2195339

KEYWORDS: MODIS, Luminescence, Magnesium, Backscatter, Data modeling, Neural networks, Absorption, Evolutionary algorithms, Satellites, Algorithm development

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Proceedings Article | 1 September 2015 Paper

Characterization of sun and sky glint from wind ruffled sea surfaces for improved estimation of polarized remote sensing reflectance

Robert Foster, Amir Ibrahim, Alex Gilerson, Ahmed El-Habashi, Carlos Carrizo, Sam Ahmed

Proceedings Volume 9613, 96130W (2015) https://doi.org/10.1117/12.2190652

KEYWORDS: Monte Carlo methods, Sensors, Sun, Electroluminescent displays, Radiative transfer, Matrices, Radiometry, Polarization, Aerosols, Scattering

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Proceedings Article | 21 May 2015 Paper

The challenges of implementing and testing two signal processing algorithms for high rep-rate Coherent Doppler Lidar for wind sensing

S. Abdelazim, D. Santoro, M. Arend, F. Moshary, S. Ahmed

Proceedings Volume 9474, 94741B (2015) https://doi.org/10.1117/12.2176897

KEYWORDS: Signal processing, Field programmable gate arrays, Digital electronics, Logic, Doppler effect, LIDAR, Spatial resolution, Electronic filtering, Linear filtering, Remote sensing

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Proceedings Article | 14 October 2014 Paper

Retrieval of water optical properties using polarization of light underwater: case I and II waters

Alexander Gilerson, Amir Ibrahim, Robert Foster, Carlos Carrizo, Ahmed El-Habashi, Samir Ahmed

Proceedings Volume 9240, 92400R (2014) https://doi.org/10.1117/12.2067963

KEYWORDS: Scattering, Water, Absorption, Polarization, Sun, Signal attenuation, Particles, Ocean optics, Light scattering, Neodymium

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Proceedings Article | 14 October 2014 Paper

Remote estimation of in water constituents in coastal waters using neural networks

Soe Hlaing, Samir Ahmed, Ioannis Ioannou, Alexander Gilerson, Robert Foster, Ahmed El-Habashi, Kaveh Bastani, Michael Ondrusek

Proceedings Volume 9240, 92400T (2014) https://doi.org/10.1117/12.2067772

KEYWORDS: Absorption, Water, Neural networks, Satellites, Algorithm development, Data modeling, Computer simulations, Backscatter, MODIS, Atmospheric corrections

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Remote estimations of oceanic constituents from optical reflectance spectra in coastal waters are challenging because of the complexity of the water composition as well as difficulties in estimation of water leaving radiance in several bands possibly due to inadequacy of current atmospheric correction schemes. This work focuses on development of a multiband inversion algorithm that combines remote sensing reflectance measurements at several wavelengths in the blue, green and red for retrievals of the absorption coefficients of phytoplankton, color dissolved organic matter and nonalgal particulates at 443nm as well as the particulate backscatter coefficient at 443nm. The algorithm was developed, using neural networks (NN), and was designed to use as input measurements on ocean color bands matching those of the Visible Infrared Imaging Radiometer Suite (VIIRS). The NN is trained on a simulated data set generated through a biooptical model for a broad range of typical coastal water parameters. The NN was evaluated using several statistical indicators, initially on the simulated data-set, as well as on field data from the NASA bio-Optical Marine Algorithm Data set, NOMAD, and data from our own field campaigns in the Chesapeake Bay which represent well the range of water optical properties as well as chlorophyll concentrations in coastal regions. The algorithm was also finally applied on a satellite - in situ databases that were assembled for the Chesapeake Bay region using MODIS and VIIRS satellite data. These databases were created using in-situ chlorophyll concentrations routinely measured in different locations throughout Chesapeake Bay and satellite reflectance overpass data that coexist in time with these in-situ measurements. NN application on this data-sets suggests that the blue (412 and 443nm) satellite bands are erroneous. The NN which was assessed for retrievals from VIIRS using only the 486, 551 and 671 bands showed that retrievals that omitted the 671 nm band was the most effective, possibly indicating an inaccuracy in the VIIRS 671 band that needs to be further investigated.

Proceedings Article | 23 May 2014 Paper

Algorithms for the remote estimation of chlorophyll-a in the Chesapeake Bay

I. Ioannou, A. Gilerson, M. Ondrusek, Robert Foster, Ahmed El-Habashi, K. Bastani, S. Ahmed

Proceedings Volume 9111, 911118 (2014) https://doi.org/10.1117/12.2053753

KEYWORDS: Near infrared, Algorithm development, Neural networks, Absorption, Evolutionary algorithms, Satellites, Sensors, Reflectivity, Data modeling, MODIS

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Proceedings Article | 23 May 2014 Paper

Underwater imaging of polarized targets

Parrish Brady, Molly Cummings, Alexander Gilerson, Yalong Gu, Carlos Carrizo, Amir Ibrahim, Ahmed El-Habashi, Robert Foster, Samir Ahmed

Proceedings Volume 9111, 91110N (2014) https://doi.org/10.1117/12.2053749

KEYWORDS: Point spread functions, Cameras, Light scattering, Polarization, Polarimetry, Mirrors, Imaging systems, Submerged target modeling, Monte Carlo methods, Scattering

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Proceedings Article | 21 May 2014 Paper

Polarization analysis of target imaging in an underwater environment

Alexander Gilerson, Yalong Gu, Carlos Carrizo, Amir Ibrahim, Samir Ahmed

Proceedings Volume 9099, 90990X (2014) https://doi.org/10.1117/12.2053750

KEYWORDS: Point spread functions, Light scattering, Cameras, Polarization, Scattering, Monte Carlo methods, Underwater imaging, Imaging systems, Submerged target modeling, Polarimetry

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Proceedings Article | 16 October 2013 Paper

Polarization of light in shallow waters

Alexander Gilerson, Amir Ibrahim, Jan Stepinski, Samir Ahmed

Proceedings Volume 8888, 88880G (2013) https://doi.org/10.1117/12.2029247

KEYWORDS: Scattering, Polarization, Water, Light scattering, Reflectivity, Radiative transfer, Device simulation, Ocean optics, Rayleigh scattering, Atmospheric modeling

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Proceedings Article | 16 October 2013 Paper

Evaluation of ocean color data processing schemes for VIIRS sensor using in-situ data of coastal AERONET-OC sites

S. Ahmed, A. Gilerson, S. Hlaing, A. Weidemann, R. Arnone, M. Wang

Proceedings Volume 8888, 88880H (2013) https://doi.org/10.1117/12.2028821

KEYWORDS: Calibration, Sensors, MODIS, Satellites, Data processing, Water, Avalanche photodetectors, Ocean optics, Atmospheric modeling, Aerosols

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In the processing of Ocean Color (OC) data from sensor data recorded by Visible Infrared Imaging Radiometer Suite (VIIRS) aboard JPSS-Suomi satellite, NASA Ocean Biology Processing Group (OBPG) is deriving a continuous temporal calibration based on the on-board calibration measurements for the visible bands, and then reprocessing the full mission to produce a continuously calibrated sensor data record (SDR) product. In addition, a vicarious calibration during SDR to OC Level-2 processing is applied. In the latest processing the vicarious calibration is derived from the Marine Optical Buoy (MOBY) data, whereas in the initial processing it was derived from a sea surface reflectance model and a climatology of chlorophyll-a concentration. Furthermore, NASA has recently reprocessed the OC data for the entire VIIRS mission with lunar-based temporal calibration and updated vicarious gains. On the other hand, in fulfilling the mission of the U.S. National Oceanic and Atmospheric Administration (NOAA), the Interface Data Processing Segment (IDPS) developed by Raytheon Intelligence and Information Systems, for the processing of the environmental data products from sensor data records, has gained beta status for evaluation. As these processing schemes continue to evolve, monitoring the validity and assessments of the related VIIRS ocean color products are necessary, especially for coastal waters, to evaluate the consistency of these processing and calibration schemes. The ocean color component of the Aerosol Robotic Network (AERONET-OC) has been designed to support long-term satellite ocean color investigations through cross-site measurements collected by autonomous multispectral radiometer systems deployed above water. As part of this network, the Long Island Sound Coastal Observatory (LISCO) near New York City and WaveCIS in the Gulf of Mexico expand those observational capabilities with continuous monitoring as well as (for the LISCO site) additional assessment of the hyper-spectral properties of coastal waters. In the investigations carried out over a one and half year period dataset of VIIRS, based on the data from two coastal AERONET-OC sites, it has been observed that the VIIRS sensor captures well the seasonal and temporal variations in the nLw data, exhibiting significant correlation with in-situ data (R = 0.929 and 0.985 for LISCO and WaveCIS respectively). For the WaveCIS site, VIIRS nLw data retrievals are seen to be enhanced with each incremental adjustments of vicarious and calibration procedures. However, that is not the case for the LISCO site which exhibits more frequent occurrences of negative water-leaving radiances, while underestimation in VIIRS nLw data is further exacerbated. Strong consistency between the time-series nLw data retrieved from the VIIRS and MODIS sensors was also observed.

Proceedings Article | 27 September 2013 Paper

The retrieval of scattering coefficient of marine particles from polarimetric observations

Amir Ibrahim, Alex Gilerson, Jan Stepinski, Ahmed El-Habashi, Samir Ahmed

Proceedings Volume 8873, 88730U (2013) https://doi.org/10.1117/12.2023546

KEYWORDS: Scattering, Particles, Sun, Light scattering, Water, Polarization, Absorption, Atmospheric modeling, Signal attenuation, Atmospheric particles

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Proceedings Article | 5 August 2013 Paper

Neural network approach to separate the non-algal absorption coefficient into dissolved and particulate

Ioannis Ioannou, Robert Foster, Alex Gilerson, Sam Ahmed

Proceedings Volume 8795, 87951N (2013) https://doi.org/10.1117/12.2028379

KEYWORDS: Absorption, Neural networks, Remote sensing, Reflectivity, Satellites, MODIS, Algorithm development, Sensors, Visible radiation, Water

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Proceedings Article | 3 June 2013 Paper

Neural network approach for the derivation of chlorophyll concentration from ocean color

Ioannis Ioannou, Alex Gilerson, Barry Gross, Fred Moshary, Sam Ahmed, Robert Foster

Proceedings Volume 8724, 87240P (2013) https://doi.org/10.1117/12.2018143

KEYWORDS: MODIS, Reflectivity, Water, Neural networks, Algorithm development, Absorption, Satellites, Remote sensing, Ocean optics, Data modeling

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Proceedings Article | 3 June 2013 Paper

Polarimetric imaging of underwater targets

Alex Gilerson, Alberto Tonizzo, Carlos Carrizo, Ahmed El-Habashi, Samir Ahmed, Amir Ibrahim, Robert Foster

Proceedings Volume 8724, 872403 (2013) https://doi.org/10.1117/12.2018132

KEYWORDS: Cameras, Polarization, Scattering, Polarizers, Polarimetry, Mirrors, Light scattering, Water, Signal attenuation, Absorption

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Proceedings Article | 3 June 2013 Paper

Evaluation of VIIRS ocean color data using measurements from the AERONET-OC sites

Alex Gilerson, Soe Hlaing, Ioannis Ioannou, Menghua Wang, Alan Weidemann, Robert Arnone, Samir Ahmed

Proceedings Volume 8724, 87240L (2013) https://doi.org/10.1117/12.2017756

KEYWORDS: MODIS, Satellites, Aerosols, Sensors, Calibration, Statistical analysis, Atmospheric corrections, Avalanche photodetectors, Data processing, Ocean optics

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Proceedings Article | 19 October 2012 Paper

Algal fluorescence: impact and potential for retrieval from measurements of the underwater degree of polarization

B. Gross, S. Ahmed, F. Moshary, A. Ibrahim, A. Gilerson, A. Tonizzo

Proceedings Volume 8532, 85320I (2012) https://doi.org/10.1117/12.974337

KEYWORDS: Luminescence, Polarization, Scattering, Water, Reflectivity, Light scattering, Particles, Absorption, Radiative transfer, Near infrared

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Proceedings Article | 12 June 2012 Paper

Validation of the VIIRS ocean color

Curtiss Davis, Jennifer Bowers, Michael Ondrusek, Sherwin Ladner, Samuel Ahmed, Giulietta Fargion, Robert Arnone, Charles Trees, Adam Lawson, Paul Martinolich, ZongPing Lee, Giuseppe Zibordi

Proceedings Volume 8372, 83720G (2012) https://doi.org/10.1117/12.922949

KEYWORDS: MODIS, Satellites, Sensors, Calibration, Satellite imaging, Ocean optics, Remote sensing, Databases, Reflectivity, Satellite navigation systems

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The Joint Polar Satellite System (JPSS) launched the Suomi National Polar-Orbiting Partnership (NPP) satellite including the Visible Infrared Imager Radiometer Suite (VIIRS) on October 28, 2011 which has the capability to monitor ocean color properties. Four months after launch, we present an initial assessment of the VIIRS ocean color products including inter-comparisons with satellite and in situ observations. Satellite ocean color is used to characterize water quality properties, however, this requires that the sensor is well characterized and calibrated, and that processing addresses atmospheric correction to derive radiometric water leaving radiance (nLw ). These radiometric properties are used to retrieve products such as chlorophyll, optical backscattering and absorption. The JPSS ocean calibration and validation program for VIIRS establishes methods and procedures to insure the accuracy of the retrieved ocean satellite products and to provide methods to improve algorithms and characterize the product uncertainty. A global monitoring network was established to integrate in situ data collection with satellite retrieved water leaving radiance values from ocean color satellites including Moderate Resolution Imaging Spectroradiometer (MODIS), MEdium Resolution Imaging Spectrometer (MERIS) and VIIRS. The global network provides a monitoring capability to evaluate the quality of the VIIRS nLw in different areas around the world and enables an evaluation and validation of the products using in situ data and other satellites. Monitoring of ocean color satellite retrievals is performed by tracking the "gain" at the Top of the Atmosphere (TOA) and then performing a vicarious adjustment fo reach site. VIIRS ocean color products are compared with MODIS and MERIS retrieved nLw and chlorophyll, and have been shown to provide similar quality. We believe that VIIRS can provide a follow-on to MODIS and MERIS equivalent ocean color products for operational monitoring of water quality. Additional research, including an assessment of stability, a full characterization of the sensor and algorithm comparisons is underway. Weekly sensor calibration tables (look up tables) are produced by JPSS and an evaluation of their impact on ocean color products is ongoing.

Proceedings Article | 12 June 2012 Paper

Polarization techniques for the retrieval of water parameters from above and below water polarimetric observations

Alberto Tonizzo, Alex Gilerson, Amir Ibrahim, Tristan Harmel, Samir Ahmed

Proceedings Volume 8372, 83720T (2012) https://doi.org/10.1117/12.919935

KEYWORDS: Particles, Scattering, Absorption, Polarization, Water, Signal attenuation, Sun, Refractive index, Optical properties, Light scattering

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Proceedings Article | 12 June 2012 Paper

Evaluation of atmospheric correction procedures for ocean color data processing using hyper- and multi-spectral radiometric measurements from the Long Island Sound Coastal Observatory

S. Hlaing, S. Ahmed, T. Harmel, R. Arnone, A. Weidemann, A. Tonizzo, A. Gilerson

Proceedings Volume 8372, 83720M (2012) https://doi.org/10.1117/12.919900

KEYWORDS: Satellites, Aerosols, Atmospheric corrections, MODIS, Atmospheric particles, Data processing, Atmospheric optics, Reflectivity, Atmospheric modeling, Sensors

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Proceedings Article | 11 June 2012 Paper

Polarimetric imaging and radiometry in shallow waters

Sam Ahmed, Jean-Paul Israel, Alberto Tonizzo, Alexander Gilerson, Carlos Carrizo

Proceedings Volume 8364, 83640U (2012) https://doi.org/10.1117/12.919938

KEYWORDS: Cameras, Polarimetry, Scattering, Polarization, Light scattering, Point spread functions, Signal attenuation, Modulation transfer functions, Sensors, Radiometry

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Proceedings Article | 26 October 2011 Paper

Retrieval of aerosol and cloud properties using multiwavelength elastic-Raman lidar

Fred Moshary, Barry Gross, Yonghua Wu, Lina Cordero, Chuen-meei Gan, Sam Ahmed

Proceedings Volume 8177, 81770M (2011) https://doi.org/10.1117/12.916579

KEYWORDS: Clouds, LIDAR, Aerosols, Backscatter, Calibration, Raman spectroscopy, Scattering, Signal attenuation, Atmospheric modeling, Mass attenuation coefficient

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Proceedings Article | 26 October 2011 Paper

Application of a multifilter shadowband radiometer and microwave radiometer for ground based evaluation of aerosol-cloud interactions

Lina Cordero, Fred Moshary, Julia He, Barry Gross, Sam Ahmed, Bomidi Madhalvan

Proceedings Volume 8177, 81770N (2011) https://doi.org/10.1117/12.898366

KEYWORDS: Clouds, Aerosols, Radiometry, Atmospheric modeling, Satellites, Microwave radiation, Atmospheric particles, Atmospheric optics, Remote sensing, Error analysis

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Proceedings Article | 8 October 2011 Paper

Bidirectional reflectance function in coastal waters: modeling and validation

Alan Weidemann, Alex Gilerson, Tristan Harmel, Robert Arnone, Soe Hlaing, Samir Ahmed, Alberto Tonizzo

Proceedings Volume 8175, 81750O (2011) https://doi.org/10.1117/12.898449

KEYWORDS: Reflectivity, Remote sensing, Magnesium, Bidirectional reflectance transmission function, Water, Computer simulations, Coastal modeling, Backscatter, Sensors, Data modeling

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Proceedings Article | 8 October 2011 Paper

Uncertainties assessment and satellite validation over 2 years time series of multispectral and hyperspectral measurements in coastal waters at Long Island Sound Coastal Observatory

A. Tonizzo, S. Hlaing, A. Gilerson, T. Harmel, S. Ahmed, R. Arnone, A. Weidemann

Proceedings Volume 8175, 817505 (2011) https://doi.org/10.1117/12.898299

KEYWORDS: Satellites, MODIS, Aerosols, Atmospheric optics, Data processing, Atmospheric particles, Atmospheric corrections, Remote sensing, Ocean optics, Calibration

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Proceedings Article | 8 October 2011 Paper

Measuring underwater polarization field from above-water hyperspectral instrumentation for water composition retrieval

A. Ibrahim, S. Ahmed, T. Harmel, A. Tonizzo, A. Gilerson, J. Chowdhary

Proceedings Volume 8175, 817509 (2011) https://doi.org/10.1117/12.898261

KEYWORDS: Polarization, Aerosols, Atmospheric modeling, Sensors, Water, Radiative transfer, Absorption, Scattering, Reflection, Signal attenuation

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Proceedings Article | 4 October 2011 Paper

Field programmable gate array processing of eye-safe all-fiber coherent wind Doppler lidar return signals

M. Arend, D. Santoro, S. Ahmed, F. Moshary, S. Abdelazim

Proceedings Volume 8182, 81820K (2011) https://doi.org/10.1117/12.898414

KEYWORDS: Signal processing, Field programmable gate arrays, LIDAR, Doppler effect, Wind measurement, Data acquisition, Signal detection, Remote sensing, Bragg cells, Digital signal processing

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Proceedings Article | 10 September 2011 Paper

Exploring the relation between polarized light fields and physical-optical characteristics of the ocean for remote sensing applications

Alberto Tonizzo, Tristan Harmel, Samir Ahmed, Alex Gilerson, Ioannis Ioannou, Amir Ibrahim

Proceedings Volume 8160, 81600H (2011) https://doi.org/10.1117/12.894113

KEYWORDS: Particles, Scattering, Water, Polarization, Sun, Refractive index, Signal attenuation, Light scattering, Absorption, Optical properties

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Proceedings Article | 5 May 2011 Paper

Hyperspectral and multispectral above-water radiometric measurements to monitor satellite data quality over coastal area

Alexander Gilerson, Soe Hlaing, Tristan Harmel, Curtiss Davis, Alberto Tonizzo, Robert Arnone, Alan Weidemann, Samir Ahmed

Proceedings Volume 8030, 803002 (2011) https://doi.org/10.1117/12.884674

KEYWORDS: Satellites, Sun, Data processing, Calibration, Sensors, Atmospheric corrections, Radiometry, Remote sensing, MODIS, Reflectivity

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Proceedings Article | 5 May 2011 Paper

Estimation of the attenuation coefficient of the water body using polarimetric observations

Alberto Tonizzo, Samir Ahmed, Tristan Harmel, Alex Gilerson, Amir Ibrahim

Proceedings Volume 8030, 803003 (2011) https://doi.org/10.1117/12.884675

KEYWORDS: Scattering, Particles, Signal attenuation, Absorption, Water, Radiative transfer, Light scattering, Polarization, Atmospheric particles, Optical properties

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Proceedings Article | 26 October 2010 Paper

Potential investigation of cloud-aerosol interaction with a multiple-wavelength Raman-elastic lidar

Chuen-meei Gan, Samir Ahmed, Fred Moshary, Yonghua Wu, Lina Cordero, Barry Gross

Proceedings Volume 7832, 78320G (2010) https://doi.org/10.1117/12.865148

KEYWORDS: Clouds, LIDAR, Aerosols, Backscatter, Optical properties, Atmospheric modeling, Raman spectroscopy, Mass attenuation coefficient, Calibration, Atmospheric particles

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Proceedings Article | 26 October 2010 Paper

PBL-height derivation from the CALIOP/CALIPSO and comparing with the radiosonde and ground-based lidar measurements

Lina Cordero, Chuen-Meei Gan, Fred Moshary, Sam Ahmed, Barry Gross, Yonghua Wu

Proceedings Volume 7832, 78320C (2010) https://doi.org/10.1117/12.865146

KEYWORDS: LIDAR, Backscatter, Aerosols, Clouds, Wavelet transforms, Troposphere, Wavelets, Atmospheric modeling, Remote sensing, Scattering

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Proceedings Article | 26 October 2010 Paper

Development of a fiber-based eye safe coherent wind lidar system for urban wind field measurements

Sameh Abdelazim, Sam Ahmed, Barry Gross, Fred Moshary, David Santoro, Mark Arend

Proceedings Volume 7832, 783206 (2010) https://doi.org/10.1117/12.865051

KEYWORDS: LIDAR, Signal detection, Oscillators, Signal processing, Signal to noise ratio, Wind measurement, Sensors, Transmitters, Fiber lasers, Eye

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Proceedings Article | 18 October 2010 Paper

Sensitivity of the above water polarized reflectance to the water composition

F. Moshary, S. Ahmed, A. Gilerson, A. Ibrahim, S. Hlaing, A. Tonizzo, J. Chowdhary, I. Ioannou, T. Harmel, B. Gross

Proceedings Volume 7825, 78250F (2010) https://doi.org/10.1117/12.865510

KEYWORDS: Sensors, Radiative transfer, Polarization, Absorption, Scattering, Water, Reflectivity, Atmospheric modeling, Contamination, Satellites

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Estimating the Stokes vector components of the polarized water radiance from above water measurements is a challenging task, mainly because of their small magnitude and the strong contamination by the sky light reflected on the sea surface. Consequently, in most applications the Stokes vector components are considered equal to zero except of I, the total reflectance. In this study, both below and above water measurements are used to assess the feasibility of such retrievals and their use to determine the water composition. In-water inherent optical properties (IOPs) were measured with commercially available instrumentation. In addition, in-water polarization characteristics were measured by our multi-angular hyperspectral sensor which provided the Stokes components for a scattering angles range of the 0-180° and a full spectral range between 400 and 750 nm. Second, a customized HyperSAS (Satlantic) instrument is used from the coastal platform in Long Island Sound, NY (LISCO) acquiring above water measurements. That instrumentation includes, in the standard configuration, two hyperspectral radiance sensors for measuring upwelling and sky radiances and one irradiance sensor for measuring downwelling irradiance. In our installation, HyperSAS capabilities were augmented by adding two radiance sensors having two polarizers oriented at 0 and 45°, with respect to a reference axis ("HyperSAS-POL"). An ad hoc procedure, which included measurements and radiative transfer computations, has been developed enabling to estimate the contribution of the sky glint and subtract it from the signal directly measured by HyperSAS-POL. As a result, the retrieved spectral shape of the underwater degree of polarization is consistent with what obtained from in situ underwater measurements and depends on the IOPs of the ocean itself. In addition, the demonstrated correctness of this polarized measurements from LISCO site enable us to provide continuous time series from the beginning of June 2010.

Proceedings Article | 7 October 2010 Paper

Quantification and assessment of urban surface reflection ratios and their effect on aerosol retrieval using high spatial resolution LANDSAT retrievals

Bomidi Madhavan, Fred Moshary, Barry Gross, Ana Picon, Sam Ahmed

Proceedings Volume 7824, 782402 (2010) https://doi.org/10.1117/12.865143

KEYWORDS: Aerosols, Vegetation, Reflectivity, Landsat, Atmospheric particles, MODIS, Reflection, Atmospheric modeling, Scattering, Earth observing sensors

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Proceedings Article | 7 October 2010 Paper

Validation of ocean color satellite sensors using coastal observational platform in Long Island Sound

Soe Hlaing, Alexander Gilerson, Samir Ahmed, Ioannis Ioannou, Tristan Harmel, Alberto Tonizzo, Amir Ibrahim

Proceedings Volume 7825, 782504 (2010) https://doi.org/10.1117/12.865123

KEYWORDS: Satellites, Calibration, MODIS, Sensors, Avalanche photodetectors, Remote sensing, Radiometry, Atmospheric corrections, Ocean optics, Hyperspectral imaging

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Proceedings Article | 4 May 2010 Paper

Mid-infrared backscattering measurements of building materials using a quantum cascade laser

Barry Gross, Maung Lwin, Fred Moshary, Paul Corrigan, Samir Ahmed

Proceedings Volume 7660, 766043 (2010) https://doi.org/10.1117/12.852679

KEYWORDS: Quantum cascade lasers, Reflectivity, Backscatter, FT-IR spectroscopy, Aluminum, Ceramics, Polishing, Surface finishing, Reflection, Mid-IR

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Proceedings Article | 29 April 2010 Paper

LIDAR, TEOM, and sunphotometer measured and model reconstructed atmospheric parameters

Yonghua Wu, Fred Moshary, Daniela Viviana Vladutescu, Barry Gross, Samir Ahmed

Proceedings Volume 7684, 76840K (2010) https://doi.org/10.1117/12.850521

KEYWORDS: LIDAR, Atmospheric modeling, Aerosols, Backscatter, Refractive index, Atmospheric particles, Clouds, Climatology, Atmospheric monitoring, Raman spectroscopy

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Proceedings Article | 20 April 2010 Paper

The impact of algal fluorescence on the underwater polarized light field

A. Tonizzo, B. Gross, A. Ibrahim, F. Moshary, S. Ahmed, J. Zhou, A. Gilerson

Proceedings Volume 7678, 76780K (2010) https://doi.org/10.1117/12.850927

KEYWORDS: Luminescence, Polarization, Water, Scattering, Absorption, Particles, Radiative transfer, Refractive index, Reflectivity, Atmospheric particles

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Proceedings Article | 20 April 2010 Paper

Underwater polarization characteristics and their impact on water visibility

Sam Ahmed, Alex Gilerson, Jing Zhou, Barry Gross, Alberto Tonizzo, Fred Moshary

Proceedings Volume 7678, 76780J (2010) https://doi.org/10.1117/12.851021

KEYWORDS: Scattering, Polarization, Light scattering, Polarizers, Visibility, Sensors, Modulation transfer functions, Cameras, Water, Signal attenuation

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Proceedings Article | 20 April 2010 Paper

Characterizing bio-optical and ecological features of algal bloom waters for detection and tracking from space

R. Amin, S. Hlaing, P. Alabi, S. Ahmed, F. Shariar, A. Gilerson, M. Grossberg, I. Gladkova

Proceedings Volume 7678, 767804 (2010) https://doi.org/10.1117/12.852444

KEYWORDS: Luminescence, Satellites, Scattering, MODIS, Reflectivity, Backscatter, Databases, Sensors, Earth observing sensors, Detection and tracking algorithms

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Proceedings Article | 20 April 2010 Paper

Estimation of the polarized water leaving radiance from above water measurements

M. Twardowski, S. Ahmed, B. Gross, A. Tonizzo, J. Zhou, F. Moshary, A. Gilerson, A. Ibrahim

Proceedings Volume 7678, 767803 (2010) https://doi.org/10.1117/12.850930

KEYWORDS: Water, Sensors, Absorption, Polarization, Signal attenuation, Scattering, Ocean optics, Optical properties, Particles, Reflectivity

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Proceedings Article | 9 October 2009 Paper

Aerosol plume observations by the ground-based lidar, sunphotometer, and satellite: cases analysis

Chuen-meei Gan, Yonghua Wu, Fred Moshary, Sam Ahmed, Barry Gross

Proceedings Volume 7479, 74790U (2009) https://doi.org/10.1117/12.830639

KEYWORDS: Aerosols, LIDAR, Clouds, Satellites, MODIS, Mass attenuation coefficient, Backscatter, Signal attenuation, Atmospheric particles, Refractive index

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Proceedings Article | 9 October 2009 Paper

Improvement of optical depth relations to PM2.5 concentrations using lidar derived PBL heights

S. Ahmed, Y. Wu, S. Chaw, B. Gross, F. Moshary

Proceedings Volume 7479, 747906 (2009) https://doi.org/10.1117/12.830664

KEYWORDS: MODIS, Aerosols, Atmospheric modeling, Satellites, LIDAR, Data modeling, Remote sensing, Sensors, Atmospheric particles, Phase modulation

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Proceedings Article | 9 October 2009 Paper

Comparison of lidar calibration at 1064-nm channel using the water-phase and cirrus clouds

Fred Moshary, Shuki Chaw, Yonghua Wu, Sam Ahmed, Barry Gross

Proceedings Volume 7479, 74790V (2009) https://doi.org/10.1117/12.830643

KEYWORDS: LIDAR, Clouds, Calibration, Aerosols, Backscatter, Transmittance, Scattering, Signal detection, Signal attenuation, Signal to noise ratio

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Proceedings Article | 7 October 2009 Paper

Development of urban surface models for improved aerosol retrieval

Ana Picon, Eduardo Hernandez, Samir Ahmed, Min Oo, Matthias Jerg, Fred Moshary, Barry Gross

Proceedings Volume 7478, 74780U (2009) https://doi.org/10.1117/12.830666

KEYWORDS: Reflectivity, MODIS, Aerosols, Atmospheric modeling, Clouds, Vegetation, Spatial resolution, Data modeling, Scattering, Radiometry

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Proceedings Article | 10 September 2009 Paper

Multiangular hyperspectral investigation of polarized light in case 2 waters

B. Gross, A. Gilerson, J. Zhou, F. Moshary, S. Ahmed, J. Chowdhary, A. Tonizzo

Proceedings Volume 7473, 747306 (2009) https://doi.org/10.1117/12.830629

KEYWORDS: Particles, Water, Absorption, Refractive index, Minerals, Polarization, Signal attenuation, Scattering, Radiative transfer, Remote sensing

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Proceedings Article | 10 September 2009 Paper

New algorithm for MODIS chlorophyll fluorescence height retrieval: performance and comparison with the current product

A. Gilerson, J. Zhou, I. Ioannou, S. Ahmed, B. Gross, F. Moshary

Proceedings Volume 7473, 747309 (2009) https://doi.org/10.1117/12.830630

KEYWORDS: Luminescence, MODIS, Absorption, Reflectivity, Sensors, Scattering, Satellites, Signal detection, Computer simulations, Algorithm development

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Proceedings Article | 10 September 2009 Paper

MODIS and MERIS detection of dinoflagellates blooms using the RBD technique

B. Gross, A. Gilerson, R. Amin, S. Ahmed, F. Moshary

Proceedings Volume 7473, 747304 (2009) https://doi.org/10.1117/12.830631

KEYWORDS: MODIS, Water, Ocean optics, Luminescence, Satellites, Backscatter, Sensors, Signal detection, Atmospheric corrections, Clouds

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Proceedings Article | 19 August 2009 Paper

Assessment of 412nm bio-optical reflectance estimator for use in atmospheric correction

Jing Zhou, Marco Vargas, Samir Ahmed, Fred Moshary, Alexander Gilerson, Barry Gross

Proceedings Volume 7459, 745904 (2009) https://doi.org/10.1117/12.826272

KEYWORDS: Aerosols, Reflectivity, Atmospheric modeling, Biological research, Atmospheric corrections, Atmospheric particles, Short wave infrared radiation, Near infrared, Coastal modeling, Absorption

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Proceedings Article | 19 August 2009 Paper

Evaluation of solar stimulated CDOM fluorescence and its impact on the closure of remote sensing reflectance

S. Hlaing, F. Moshary, B. Gross, S. Ahmed, A. Gilerson, I. Ioannou, J. Zhou, A. Tonizzo

Proceedings Volume 7459, 74590B (2009) https://doi.org/10.1117/12.825374

KEYWORDS: Luminescence, Reflectivity, Absorption, Remote sensing, Backscatter, Quantum efficiency, Optical properties, Fluorescence spectroscopy, Spectroscopy, Radiative transfer

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Proceedings Article | 19 August 2009 Paper

Inversion of inherent optical properties of water using artificial neural network techniques for coastal water

I. Ioannou, B. Gross, F. Moshary, S. Ahmed, J. Zhou, A. Gilerson

Proceedings Volume 7459, 745909 (2009) https://doi.org/10.1117/12.825386

KEYWORDS: Absorption, Data modeling, Water, Backscatter, Ultraviolet radiation, Neural networks, Reflectivity, Optical properties, Computer simulations, Remote sensing

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