Analysis of seagrass reflectivity by using a water column correction algorithm

Seagrass in optically shallow water can generate optical signals that can be tracked remotely. Unfortunately the signals from the bottom are relatively weak and can be affected by the water column when concentrations of suspended particles, chlorophyll and coloured dissolved organic matter are high. An optical model simulating the propagation of light for retrieving the bottom reflectance was developed. Implementation of the method was found to be effective for improving the accuracy of coastal habitat maps, and essential for deriving empirical relationships between remotely sensed data and interesting features in the marine environment. The appropriate wavebands for seagrass mapping, which generally lay between 500 and 630 nm and 680 and 710 nm, were obtained by means of full visual inspection and analysis of the correct spectra. Additionally, a strong relationship between the reflectance value at 715 nm and Leaf Area Index was found, with a correlation coefficient of 0.99.

[1]  P. Ralph,et al.  Operation of the xanthophyll cycle in the seagrass Zostera marina in response to variable irradiance , 2002 .

[2]  Trijntje Valerie Downes,et al.  Interpretation of hyperspectral remote-sensing imagery by spectrum matching and look-up tables. , 2005, Applied optics.

[3]  David R. Lyzenga,et al.  Shallow-water bathymetry using combined lidar and passive multispectral scanner data , 1985 .

[4]  D. Lyzenga.  Remote sensing of bottom reflectance and water attenuation parameters in shallow water using aircraft and Landsat data , 1981 .

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

[6]  Robert A. Leathers,et al.  Optical remote sensing of benthic habitats and bathymetry in coastal environments at Lee Stocking Island, Bahamas: A comparative spectral classification approach , 2003 .

[7]  G. Zibordi.  Marine optics: field radiometry , 2007 .

[8]  L. C. Henyey,et al.  Diffuse radiation in the Galaxy , 1940 .

[9]  B Gentili,et al.  Diffuse reflectance of oceanic waters. II Bidirectional aspects. , 1993, Applied optics.

[10]  M. Chami,et al.  Influence of the angular shape of the volume-scattering function and multiple scattering on remote sensing reflectance. , 2006, Applied optics.

[11]  James W. Brown,et al.  A semianalytic radiance model of ocean color , 1988 .

[12]  K. Stamnes,et al.  Comparison of numerical models for computing underwater light fields. , 1993, Applied optics.

[13]  S. Enríquez.  Light absorption efficiency and the package effect in the leaves of the seagrass Thalassia testudinum , 2005 .

[14]  K. Moore,et al.  Chesapeake Bay: An Unprecedented Decline in Submerged Aquatic Vegetation , 1983, Science.

[15]  H. Gons,et al.  Optical teledetection of chlorophyll a in turbid inland waters , 1999 .

[16]  C. Mobley,et al.  Estimation of the remote-sensing reflectance from above-surface measurements. , 1999, Applied optics.

[17]  Shunlin Liang,et al.  Recent developments in estimating land surface biogeophysical variables from optical remote sensing , 2007 .

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

[19]  André Morel,et al.  Diffuse reflectance of oceanic shallow waters: influence of water depth and bottom albedo , 1994 .

[20]  J. Kirk.  The upwelling light stream in natural waters , 1989 .

[21]  Prieur,et al.  Analysis of variations in ocean color’ , 2000 .

[22]  R. Maffione,et al.  Instruments and methods for measuring the backward-scattering coefficient of ocean waters. , 1997, Applied optics.

[23]  B. Peterson,et al.  Large‐scale patterns in seagrass (Thalassia testudinum) demographics in south Florida , 2001 .

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

[25]  H. Gordon,et al.  Computed relationships between the inherent and apparent optical properties of a flat homogeneous ocean. , 1975, Applied optics.

[26]  L. Prieur,et al.  An optical classification of coastal and oceanic waters based on the specific spectral absorption curves of phytoplankton pigments, dissolved organic matter, and other particulate materials1 , 1981 .

[27]  Stuart R. Phinn,et al.  Efficient radiative transfer model inversion for remote sensing applications , 2009 .

[28]  E. Seyhan,et al.  Remote sensing as a tool for assessing water quality in Loosdrecht lakes , 1992, Hydrobiologia.

[29]  D. Lyzenga.  Passive remote sensing techniques for mapping water depth and bottom features. , 1978, Applied optics.

[30]  C. Mobley,et al.  Hyperspectral remote sensing for shallow waters. 2. Deriving bottom depths and water properties by optimization. , 1999, Applied optics.

[31]  C. A. Coombes,et al.  An opaque cloud cover model of sky short wavelength radiance , 1988 .

[32]  Chi-Kuei Wang,et al.  Using airborne bathymetric lidar to detect bottom type variation in shallow waters , 2007 .

[33]  M. Coates,et al.  Comparative methods in developmental biology. , 2001, Zoology.

[34]  Jiaguo Qi,et al.  Identifying optimal spectral bands from in situ measurements of Great Lakes coastal wetlands using second-derivative analysis , 2005 .

[35]  Jean-Marie Froidefond,et al.  Introducing a mini-catamaran to perform reflectance measurements above and below the water surface. , 2005, Optics express.

[36]  Charles H. Fletcher,et al.  Decorrelating remote sensing color bands from bathymetry in optically shallow waters , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[37]  Scott Pegau,et al.  Remote sensing reflectance: preliminary comparisons between in-water and above-water measurements and estimates modeled from measured inherent optical properties , 1997, Other Conferences.

[38]  Chaoyu Yang,et al.  Detection of Seagrass Distribution Changes from 1991 to 2006 in Xincun Bay, Hainan, with Satellite Remote Sensing , 2009, Sensors.

[39]  W. Philpot.  Radiative transfer in stratified waters: a single-scattering approximation for irradiance. , 1987, Applied optics.

[40]  Hankui Wang,et al.  The status of the ecological environment and a proposed protection strategy in Sanya Bay, Hainan Island, China. , 2003, Marine pollution bulletin.

[41]  Jennifer P. Cannizzaro,et al.  Estimating chlorophyll a concentrations from remote-sensing reflectance in optically shallow waters , 2006 .

[42]  A. Morel.  Optical properties of pure water and pure sea water , 1974 .

[43]  E. Boss,et al.  Calibrated near-forward volume scattering function obtained from the LISST particle sizer. , 2006, Optics express.

[44]  A. Dekker,et al.  Seagrass species: are they spectrally distinct? , 2001, IGARSS 2001. Scanning the Present and Resolving the Future. Proceedings. IEEE 2001 International Geoscience and Remote Sensing Symposium (Cat. No.01CH37217).

[45]  L. Prieur,et al.  Analysis of variations in ocean color1 , 1977 .