Atmospheric correction based on inherent optical properties of sea water at NIR wavelengths combined with an automated aerosol spectra determination (ASD) technique

2014 ◽  
Vol 35 (10) ◽  
pp. 3631-3650
Author(s):  
Nivedita Sanwlani ◽  
Prakash Chauhan ◽  
R.R. Navalgund
Keyword(s):  
Optical Properties ◽  
Sea Water ◽  
Atmospheric Correction ◽  
Inherent Optical Properties

scholarly journals A Hybrid Bio-Optical Transformation for Satellite Bathymetry Modeling Using Sentinel-2 Imagery

2019 ◽  
Vol 11 (23) ◽  
pp. 2746 ◽  
Author(s):  
Athanasios K. Mavraeidopoulos ◽  
Emmanouil Oikonomou ◽  
Athanasios Palikaris ◽  
Serafeim Poulos
Keyword(s):  
Optical Properties ◽  
Field Data ◽  
Sea Water ◽  
Aegean Sea ◽  
Multispectral Images ◽  
Inherent Optical Properties ◽  
Sentinel 2A ◽  
Satellite Bathymetry ◽  
Optical Transformation ◽  
Sentinel 2

The article presents a new hybrid bio-optical transformation (HBT) method for the rapid modelling of bathymetry in coastal areas. The proposed approach exploits free-of-charge multispectral images and their processing by applying limited manpower and resources. The testbed area is a strait between two Greek Islands in the Aegean Sea with many small islets and complex seabed relief. The HBT methodology implements semi-analytical and empirical steps to model sea-water inherent optical properties (IOPs) and apparent optical properties (AOPs) observed by the Sentinel-2A multispectral satellite. The relationships of the calculated IOPs and AOPs are investigated and utilized to classify the study area into sub-regions with similar water optical characteristics, where no environmental observations have previously been collected. The bathymetry model is configured using very few field data (training depths) chosen from existing official nautical charts. The assessment of the HBT indicates the potential for obtaining satellite derived bathymetry with a satisfactory accuracy for depths down to 30 m.

scholarly journals Seasonal variability of upwelling radiance polarization over the Southern Baltic surface

2017 ◽  
Author(s):  
Włodzimierz Freda
Keyword(s):  
Wind Speed ◽  
Seasonal Variability ◽  
Sea Water ◽  
Atmospheric Correction ◽  
Sea Surface ◽  
Degree Of Polarization ◽  
Strongly Correlated ◽  
Molecular Scattering ◽  
Inherent Optical Properties ◽  
Polarization Of Light

Abstract. Polarization of light may be used to improve the remote colour sensing of sea water. This can be done in a number of ways, such as limiting of sun glints, obtaining information about atmospheric aerosol properties for atmospheric correction as well as improving the interpretation of the water-leaving signal results. However polarization signals at the top of atmosphere (ToA), that include the waterleaving signal, is strongly influenced by atmospheric molecular scattering and by direct sun and sky reflections from sea surface. For these reasons, it is necessary to better understand the factors that change the polarization of light in the atmosphere-ocean system. In this paper, the influence of seasonal variability of inherent optical properties (IOPs), wind speed and solar zenith angle (SZA) on the polarization of upwelling radiance over the sea surface is discussed. The presented results come from Monte Carlo simulations, which used averaged measurements of IOPs, collected for several years, as input data. The effects of simulations are presented in the form of polar plots of the upwelling radiance degree of polarization (DoP). The results indicate that regardless of the wavelength and type of water, the highest value of the above water DoP is strongly correlated with the absorptionto-attenuation ratio. The correlation is a power function and it depends on both the SZA and the wind speed. The correlation versatility for different wavelengths is very unusual in optics of the sea and is therefore worth emphasizing.

scholarly journals Deriving inherent optical properties and associated inversion-uncertainties in the Dutch Lakes

2009 ◽  
Vol 13 (7) ◽  
pp. 1113-1121 ◽  
Author(s):  
M. S. Salama ◽  
A. Dekker ◽  
Z. Su ◽  
C. M. Mannaerts ◽  
W. Verhoef
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Atmospheric Correction ◽  
Inland Waters ◽  
Data Sets ◽  
Modified Model ◽  
Chl A ◽  
Inherent Optical Properties ◽  
Data Inversion ◽  
Suspended Particulate

Abstract. Remote sensing of water quality in inland waters requires reliable retrieval algorithms, accurate atmospheric correction and consistent method for uncertainty estimation. In this paper, the GSM semi-analytical inversion model is modified for inland waters to derive inherent optical properties (IOPs) and their spectral dependencies from air and space borne data. The modified model was validated using two data sets from the Veluwe and the Vecht Dutch lakes. For the Veluwe lakes, the model was able to derive a linear relationship between measured concentrations and estimated IOPs with R2 values above 0.7 for chlorophyll-a (Chl-a) and up to 0.9 for suspended particulate matters (SPM). In the Vecht lakes, the modified model derived accurate values of IOPs. The R2 values were 0.89 for Chl-a and up to 0.95 for SPM. The RMSE values were 0.93 mg m−3 and 0.56 g m−3 for Chl-a and SPM respectively. Finally, the IOPs of the Veluwe lakes are derived from multi-spectral, ocean color and hyperspectral airborne data. Inversion-uncertainties of the derived IOPs were also estimated using a standard nonlinear regression technique. The study shows that inversion-uncertainties of remote sensing derived IOPs are proportional to water turbidity.

scholarly journals Water remote sensing reflectance from radiative transfer simulations on a global scale of Inherent Optical Properties

2018 ◽  
Author(s):  
Lena Kritten ◽  
Rene Preusker ◽  
Carsten Brockmann ◽  
Tonio Fincke ◽  
Sampsa Koponen ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Radiative Transfer ◽  
Spectral Response ◽  
Pure Water ◽  
Atmospheric Correction ◽  
Ocean Colour ◽  
Inherent Optical Properties ◽  
Remote Sensing Reflectance ◽  
Water Constituents

Abstract. The remote-sensing reflectance (Rrs) is in someway an artificial unit, that is constructed in order to contain the spectral colour information of the water body, but to be hardly influenced by the atmosphere above. In ocean colour remotesensing it is the measure to define the optical properties of the water/water constituents. Rrs is the ratio of water-leaving radiance and down-welling irradiance. It is derived from top-of-atmosphere radiance/reflectance measurements through atmospheric correction. A database with Rrs from radiative 5 transfer simulations is capable to serve as a forward model for the retrieval of water constituents. For the present database the Rrs is simulated in dependency of inherent optical properties (IOPs) representing pure water with different salinities and 5 water constituents (Chlorophyll-a-pigment, Detritus, CDOM (coloured dissolved organic matter), a "big" and a "small" scatterer) in a global range of concentrations. The interpolation points for each IOP were chosen in order to reproduce the entire functional relationship between this particular IOP and the corresponding Rrs. The IOPs are varied independently. The data is available for 9 solar, 9 viewing zenith and 25 azimuth angles. The spectral resolution of the data is 1nm, which allows the convolution to any ocean colour sensors’ spectral response function. The data is produced with the radiative transfer code MOMO (Matrix Operator Model), which simulates the full radiative transfer in atmosphere and ocean. The code is hosted at the institute of space sciences at Freie Universität Berlin and is not publicly available. The look-up table (LUT) is available at: doi:10.1594/WDCC/LUT_for_WDC_I (Kritten et al., 2017).

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