On the Adequacy of Representing Water Reflectance by Semi-Analytical Models in Ocean Color Remote Sensing

Deterministic or statistical inversion schemes to retrieve ocean color from space often use a simplified water reflectance model that may introduce unrealistic constraints on the solution, a disadvantage compared with standard, two-step algorithms that make minimal assumptions about the water signal. In view of this, the semi-analytical models of Morel and Maritorena (2001), MM01, and Park and Ruddick (2005), PR05, used in the spectral matching POLYMER algorithm (Steinmetz et al., 2011), are examined in terms of their ability to restitute properly, i.e., with sufficient accuracy, water reflectance. The approach is to infer water reflectance at MODIS wavelengths, as in POLYMER, from theoretical simulations (using Hydrolight with fluorescence and Raman scattering) and, separately, from measurements (AERONET-OC network). A wide range of Case 1 and Case 2 waters, except extremely turbid waters, are included in the simulations and sampled in the measurements. The reflectance model parameters that give the best fit with the simulated data or the measurements are determined. The accuracy of the reconstructed water reflectance and its effect on the retrieval of inherent optical properties (IOPs) is quantified. The impact of cloud and aerosol transmittance, fixed to unity in the POLYMER scheme, on model performance is also evaluated. Agreement is generally good between model results and Hydrolight simulations or AERONET-OC values, even in optically complex waters, with discrepancies much smaller than typical atmospheric correction errors. Significant differences exist in some cases, but having a more intricate model (i.e., using more parameters) makes convergence more difficult. The trade-off is between efficiency/robustness and accuracy. Notable errors are obtained when using the model estimates to retrieve IOPs. Importantly, the model parameters that best fit the input data, in particular chlorophyll-a concentration, do not represent adequately actual values. The reconstructed water reflectance should be used in bio-optical algorithms. While neglecting cloud and aerosol transmittances degrades the accuracy of the reconstructed water reflectance and the retrieved IOPs, it negligibly affects water reflectance ratios and, therefore, any variable derived from such ratios.

[1]  H. Claustre,et al.  Variability in the chlorophyll‐specific absorption coefficients of natural phytoplankton: Analysis and parameterization , 1995 .

[2]  A. Morel,et al.  Improved detection of turbid waters from ocean color sensors information , 2006 .

[3]  G. Leshkevich,et al.  Optical Characterizations and Pursuit of Optical Closure for the Western Basin of Lake Erie through in situ Measurements , 2010 .

[4]  P Jeremy Werdell,et al.  Generalized ocean color inversion model for retrieving marine inherent optical properties. , 2013, Applied optics.

[5]  E. Fry,et al.  Absorption spectrum (380-700 nm) of pure water. II. Integrating cavity measurements. , 1997, Applied optics.

[6]  J. Haigh,et al.  Atmospheric correction over case 2 waters with an iterative fitting algorithm: relative humidity effects. , 1997, Applied optics.

[7]  Kenneth J. Voss,et al.  A spectral model of the beam attenuation coefficient in the ocean and coastal areas , 1992 .

[8]  Richard L. Miller,et al.  Bio-optical properties and ocean color algorithms for coastal waters influenced by the Mississippi River during a cold front. , 2006, Applied optics.

[9]  K. Ruddick,et al.  Model of remote-sensing reflectance including bidirectional effects for case 1 and case 2 waters. , 2005, Applied optics.

[10]  E. Boss,et al.  Influence of Raman scattering on ocean color inversion models. , 2013, Applied optics.

[11]  John A. Nelder,et al.  A Simplex Method for Function Minimization , 1965, Comput. J..

[12]  François Steinmetz,et al.  Atmospheric correction in presence of sun glint: application to MERIS. , 2011, Optics express.

[13]  P Jeremy Werdell,et al.  Performance metrics for the assessment of satellite data products: an ocean color case study. , 2018, Optics express.

[14]  K. Carder,et al.  A simple spectral solar irradiance model for cloudless maritime atmospheres , 1990 .

[15]  K. Ruddick,et al.  Seaborne measurements of near infrared water‐leaving reflectance: The similarity spectrum for turbid waters , 2006 .

[16]  Bryan A. Franz,et al.  Chlorophyll aalgorithms for oligotrophic oceans: A novel approach based on three‐band reflectance difference , 2012 .

[17]  E. Boss,et al.  Atmospheric Correction of Satellite Ocean-Color Imagery During the PACE Era , 2019, Front. Earth Sci..

[18]  Peter Regner,et al.  The Ocean Colour Climate Change Initiative: II. Spatial and Temporal Homogeneity of Satellite Data Retrieval Due to Systematic Effects in Atmospheric Correction Processors , 2015 .

[19]  R. Arnone,et al.  Deriving inherent optical properties from water color: a multiband quasi-analytical algorithm for optically deep waters. , 2002, Applied optics.

[20]  L. Prieur,et al.  A three-component model of ocean colour and its application to remote sensing of phytoplankton pigments in coastal waters , 1989 .

[21]  H. Gordon,et al.  Remote Assessment of Ocean Color for Interpretation of Satellite Visible Imagery: A Review , 1983 .

[22]  Didier Tanré,et al.  A successive order of scattering code for solving the vector equation of transfer in the earth's atmosphere with aerosols , 2007 .

[23]  A. Morel.  Optical modeling of the upper ocean in relation to its biogenous matter content (case I waters) , 1988 .

[24]  Eurico J. D'Sa,et al.  Seasonal variability and controls on chromophoric dissolved organic matter in a large river‐dominated coastal margin , 2009 .

[25]  Hui Feng,et al.  AERONET-OC: A Network for the Validation of Ocean Color Primary Products , 2009 .

[26]  Marcel Babin,et al.  Variations of light absorption by suspended particles with chlorophyll a concentration in oceanic (case 1) waters: Analysis and implications for bio-optical models , 1998 .

[27]  H. Gordon,et al.  Removal of atmospheric effects from satellite imagery of the oceans. , 1978, Applied optics.

[28]  B. Osborne,et al.  Light and Photosynthesis in Aquatic Ecosystems. , 1985 .

[29]  H. Gordon,et al.  Atmospheric correction of ocean color imagery: use of the junge power-law aerosol size distribution with variable refractive index to handle aerosol absorption. , 1998, Applied optics.

[30]  M. Kahru,et al.  Ocean Color Chlorophyll Algorithms for SEAWIFS , 1998 .

[31]  S. Maritorena,et al.  Bio-optical properties of oceanic waters: A reappraisal , 2001 .

[32]  Peter Regner,et al.  The Ocean Colour Climate Change Initiative: I. A methodology for assessing atmospheric correction processors based on in-situ measurements , 2015 .

[33]  H. Gordon,et al.  Spectral optimization for constituent retrieval in Case 2 waters I: Implementation and performance , 2009 .

[34]  André Morel,et al.  Light scattering and chlorophyll concentration in case 1 waters: A reexamination , 1998 .

[35]  M. Perry,et al.  Modeling in situ phytoplankton absorption from total absorption spectra in productive inland marine waters , 1989 .

[36]  K. Stamnes,et al.  Accurate and self-consistent ocean color algorithm: simultaneous retrieval of aerosol optical properties and chlorophyll concentrations. , 2003, Applied optics.

[37]  Maycira Costa,et al.  Bio-optical algorithm evaluation for MODIS for western Canada coastal waters: An exploratory approach using in situ reflectance , 2009 .

[38]  B. Gentili,et al.  Diffuse reflectance of oceanic waters. III. Implication of bidirectionality for the remote-sensing problem. , 1996, Applied optics.

[39]  Stephen G. Warren,et al.  Transmission of Solar Radiation by Clouds over Snow and Ice Surfaces: A Parameterization in Terms of Optical Depth, Solar Zenith Angle, and Surface Albedo , 2004 .

[40]  K. Baker,et al.  Optical properties of the clearest natural waters (200-800 nm). , 1981, Applied optics.

[41]  P. J. Werdell,et al.  An improved in-situ bio-optical data set for ocean color algorithm development and satellite data product validation , 2005 .

[42]  P. Deschamps,et al.  Atmospheric modeling for space measurements of ground reflectances, including bidirectional properties. , 1979, Applied optics.

[43]  Stéphane Maritorena,et al.  Optimization of a semianalytical ocean color model for global-scale applications. , 2002, Applied optics.

[44]  T. Nakajima,et al.  Simultaneous retrieval of aerosol optical thickness and chlorophyll concentration from multiwavelength measurement over East China Sea , 2016 .