NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Assessment of a Bidirectional Reflectance Distribution Correction of Above-Water and Satellite Water-Leaving Radiance in Coastal WatersWater-leaving radiances, retrieved from in situ or satellite measurements, need to be corrected for the bidirectional properties of the measured light in order to standardize the data and make them comparable with each other. The current operational algorithm for the correction of bidirectional effects from the satellite ocean color data is optimized for typical oceanic waters. However, versions of bidirectional reflectance correction algorithms specifically tuned for typical coastal waters and other case 2 conditions are particularly needed to improve the overall quality of those data. In order to analyze the bidirectional reflectance distribution function (BRDF) of case 2 waters, a dataset of typical remote sensing reflectances was generated through radiative transfer simulations for a large range of viewing and illumination geometries. Based on this simulated dataset, a case 2 water focused remote sensing reflectance model is proposed to correct above-water and satellite water-leaving radiance data for bidirectional effects. The proposed model is first validated with a one year time series of in situ above-water measurements acquired by collocated multispectral and hyperspectral radiometers, which have different viewing geometries installed at the Long Island Sound Coastal Observatory (LISCO). Match-ups and intercomparisons performed on these concurrent measurements show that the proposed algorithm outperforms the algorithm currently in use at all wavelengths, with average improvement of 2.4% over the spectral range. LISCO's time series data have also been used to evaluate improvements in match-up comparisons of Moderate Resolution Imaging Spectroradiometer satellite data when the proposed BRDF correction is used in lieu of the current algorithm. It is shown that the discrepancies between coincident in-situ sea-based and satellite data decreased by 3.15% with the use of the proposed algorithm.
Document ID
20120009948
Document Type
Reprint (Version printed in journal)
Authors
Hlaing, Soe (City Coll. of the City Univ. of New York NY, United States)
Gilerson, Alexander (City Coll. of the City Univ. of New York NY, United States)
Harmal, Tristan (City Coll. of the City Univ. of New York NY, United States)
Tonizzo, Alberto (City Coll. of the City Univ. of New York NY, United States)
Weidemann, Alan (Naval Research Lab. Stennis Space Center, MS, United States)
Arnone, Robert (Naval Research Lab. Stennis Space Center, MS, United States)
Ahmed, Samir (City Coll. of the City Univ. of New York NY, United States)
Date Acquired
August 25, 2013
Publication Date
January 10, 2012
Publication Information
Publication: Applied Optics
Volume: 51
Issue: 2
Subject Category
Optics
Report/Patent Number
NRL/JA/7330-11-0779
AD-A555764
Funding Number(s)
PROJECT: Proj-NNH09AM26I
Distribution Limits
Public
Copyright
Other
Keywords
LISCO(LONG ISLAND SOUND COASTAL OBSERVATORY)
BRDF(BIDIRECTIONAL REFLECTANCE DISTRIBUTION FUNCTION)
BIDIRECTIONAL PROPERTIES
WATER-LEAVING RADIANCE
COASTAL WATERS
REMOTE SENSING REFLECTANCE
73-4223-00-5