Dissertation/Thesis Abstract

Hyperspectral and Polarimetric Imaging for Advanced Characterization of the Ocean Surface and Underwater Objects
by Carrizo, Carlos, Ph.D., The City College of New York, 2018, 168; 13425979
Abstract (Summary)

Hyperspectral and polarimetric imaging of the ocean, both below and above the water surface, has increased the interest of the Ocean Color (OC) scientific community for decades in an attempt to answer questions related to climate change, monitoring of water quality, assessment of the impact of anthropogenic activities on marine life and underwater ecosystems, detection and characterization of underwater targets. These needs are recognized by worldwide efforts devoted to acquiring accurate time series measurements in open-ocean and coastal waters by OC satellite imagery to produce reliable high-quality data records, which can be used both in support of operations and in climate studies. The reliability of satellite observations of the open-ocean and coastal zones requires these remote instruments to be regularly assessed and validated against actual in-situ measurements along with related atmospheric corrections. However, despite improvements in satellite data and retrieval algorithms, accurate retrievals in coastal waters remain challenging.

Modern hyperspectral imagers usually carry out their measurements on moving platforms, aircrafts or orbiting satellites, using push-broom scanning techniques for the acquisition of 3-D data cubes (along-track, cross-track and spectral). These data, however, may not always reflect accurately the temporal variability of measurements in a very dynamic atmosphere-ocean environment, especially in coastal areas. In recent years, new technologies have made possible the exploration of snapshot hyperspectral and polarimetric imaging of the ocean in an attempt to improve the accuracy of existing methods and exploring the pixel-by-pixel variability of the signal measured, often neglected in standard approaches.

The work presented in this thesis investigates and discusses imaging of underwater polarimetric targets in various water types and the estimation of parameters of the veiling light and the attenuation coefficients responsible for image degradation and blurring as a function of the water properties. In above water observations the effects of atmospheric aerosols and wind speed on the surface reflectance coefficients are studied along with the pixel-by-pixel variability of water-leaving radiance (Lw) and its relationship to water constituents for different coastal waters and atmospheric conditions, the impact of this variability on the uncertainties in above water measurements and satellite retrievals. Validation of all results has been achieved by the comparison with the comprehensive Vector Radiative Transfer simulations of the Atmosphere-Ocean System, as well as measurements by a number of other collocated radiometric and polarimetric instruments.

Indexing (document details)
Advisor: Gilerson, Alexander A.
Commitee: Chowdhary, Jacek, Gross, Barry, Moshary, Fred, Samir, Ahmed
School: The City College of New York
Department: Electrical Engineering
School Location: United States -- New York
Source: DAI-B 80/06(E), Dissertation Abstracts International
Subjects: Hydrologic sciences, Aquatic sciences, Remote sensing
Keywords: Hyperspectral polarimetry, Linear and nonlinear light scattering from surfaces, Oceanic optics, Radiative transfer, Remote sensing and sensors, Rough surfaces, Scattering
Publication Number: 13425979
ISBN: 9780438826618
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