Download or read book Closure Between Apparent and Inherent Optical Properties of the Ocean with Applications to the Determination of Spectral Bottom Reflectance written by James Edward Ivey and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: This study focuses on comparing six different marine optical models, field measurements, and laboratory measurements. Inherent Optical Properties (IOPs) of the water column depend only on the constituents within the water, not on the ambient light field. Apparent Optical Properties (AOPs) depend both on IOPs and the geometric underwater light field resulting from solar irradiance. Absorption (a) and scattering (b) are IOPs. Scattering can be partitioned into backscattering (b[subscript b]). Remote Sensing Reflectance (R[subscript rs]), the ratio of radiant light leaving the water to the light entering the water surface plane (E[subscript d]), is an AOP. R[subscript rs] is proportional to b[subscript b]/(a + b[subscript b]). Using this relationship, R[subscript rs] is inverted to determine both absorption and backscattering. The constituents contributing to both absorption and backscattering can then be further deconvolved using modeling techniques. The in situ instruments usually have a fixed path length while AOP measurement path length depends on the penetration and/or return of downwelling solar irradiance. As a consequence, AOP measurements use a longer path length than in situ instruments. If the path length of a direct IOP measurement instrument is too short, there may not be sufficient signal to determine a change in value. While the AOP inversions require more empirical assumptions to determine IOP values than in situ instruments, they provide a higher signal to noise ratio in clearer waters. This study defines closure as the statistical agreement between instruments and methods in order to determine the same optical property. No method is considered absolute truth. An R[subscript rs] inversion algorithm was best under most of the test stations for measuring IOP values. One exception was when bottom reflectance was significant, an inversion of diffuse attenuation (the change in the natural log of E[subscript d] over depth) was better for determining absorption and a field instrument was better for determining backscattering. The relationships between AOPs and IOPs provide estimates of unmeasured optical properties. A method was developed to determine the spectral reflectance of the bottom using IOP estimates and R[subscript rs].
Download or read book The Inherent Optical Properties of the Oceans written by Andrew Heath Barnard and published by . This book was released on 2000 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precise in situ measurement of the spectral absorption and scattering coefficients in several regions has revealed patterns in the distribution of the inherent optical properties on spatial scales that were previously unobtainable. The precision of the measurements was found to be consistent and unbiased across a variety of oceanic regimes and are therefore useful for studies of radiative transfer. The spectral information obtained during this research was used to define fundamental relationships between the inherent optical properties and the apparent optical properties of the ocean. A multiple band ratio algorithm based on the relationship between the absorption coefficient and the remote sensing reflectance was developed to provide a means to test the optical measurements for closure. A large database of synoptic measurements of the spectral absorption coefficient and the remote sensing reflectance was tested for closure using this algorithm and it was found that radiative transfer works to within instrument accuracy. Furthermore, it was demonstrated that inversion to obtain the absorption coefficient is possible using this algorithm providing that the spectral dependence of the absorption coefficient can be accurately modeled. A model based on the horizontal variability in the vertical structure of the backscattering to absorption ratio was developed to predict the amplitude of an internal wave using the spatial information in the remote sensing reflectance. The results from a combined aircraft and in situ measurement experiment showed that the predicted amplitudes of the internal wave were comparable to the depth fluctuations of the thermocline observed in the in situ temperature profiles. In an effort to aid primary productivity experiments, an empirical model to predict the photosynthetically available radiation light levels from the absorption coefficient profiles at 490 nm was developed based on in situ data collected in the Gulf of California. The model was able to predict the depth of the one percent light level with a standard error of 4 m. This model provides a method to estimate the daytime light levels from nighttime absorption coefficient measurements at 490 nm.
Download or read book Closure in Optical Oceanography written by and published by . This book was released on 1995 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are interested in studying the inherent optical properties (lOP) from a theoretical as well as an experimental perspective. Radiative transfer theories linking the apparent optical properties (AOP) to the lOP will be further developed and tested. The lOP form the link between the biogeochemical nature of the suspended and dissolved materials and radiative transfer. This link must be investigated both theoretically and experimentally. The ultimate goal of this program is to be able to predict radiative transfer in the oceans given the biogeochemical nature of the suspended and dissolved materials and their distribution. Real progress in Optical Oceanography requires the ability to verify models in a variety of optical water types. We therefore directed our efforts during this grant towards optical closure. Optical closure is the simultaneous verification of optical relationships and optical instrumentation. The end result will be knowledge of the accuracy with which inherent and apparent optical properties can be measured, and the testing of a number of fundamental optical relationships, including solutions to the equation of radiative transfer and the relationship of particulate properties and inherent optical properties via Mie theory for three-layered particles.
Download or read book Remote Sensing and Geospatial Technologies for Coastal Ecosystem Assessment and Management written by Xiaojun Yang and published by Springer Science & Business Media. This book was released on 2008-12-11 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this landmark publication, leading experts detail how remote sensing and related geospatial technologies can be used for coastal ecosystem assessment and management. This book is divided into three major parts. In the first part several conceptual and technical issues of applying remote sensing and geospatial technologies in the coastal environment are examined. The second part showcases some of the latest developments in the use of remote sensing and geospatial technologies when characterizing coastal waters, submerged aquatic vegetation, benthic habitats, shorelines, coastal wetlands and watersheds. Finally, the last part demonstrates a watershed-wide synthetic approach that links upstream stressors with downstream responses for integrated coastal ecosystem assessment and management.
Download or read book Outstanding Topics in Ocean Optics written by Dariusz Stramski and published by MDPI. This book was released on 2019-04-23 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ocean optics is a branch of oceanography which is firmly embedded in studies of a great variety of ocean science and engineering questions. The interactive nature between radiative transfer of light and various dissolved and particulate constituents of seawater is at the core of ocean optics science and applications. The transfer of radiant solar energy has vital implications to life and climate on Earth, and the large variety of subjects of ocean optics ranges from the subtle problems of physical optics to optical remote sensing towards a better understanding of ocean biology, biogeochemistry and ecosystems and their roles in the Earth's system processes. The intention of this book is to present a collection of papers that generally share a common denominator of frontier topics in ocean optics which are unique, uncommon or outstanding in the literature, and to provide a balanced view of the extraordinary breadth of research in this field. Topics as diverse as measurements and modeling of radiative transfer, light fields, light scattering and polarization, ocean color, benthic optical properties, and the use of optics for characterizing seawater constituents are addressed in this book. The book is expected to be of interest and useful to a broad audience of professional ocean scientists, engineers and advanced students with an interest in ocean optics and applications of optical methods in oceanography.
Download or read book Bio Optical Properties of the Arabian Sea As Determined by in Situ and Sea WiFS Data written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-16 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this work was to characterize optical and fluorescence properties in the euphotic zone during two British Ocean Flux Study (BOFS) Arabian Sea cruises. This was later expanded in 1995 to include three U.S. JGOFS Arabian Sea Cruises. The region was to be divided into one or more "bio-optical provinces," within each of which a single set of regression models was to be developed to relate the vertical distribution of irradiance attenuation and normalized fluorescence (SF and NF) to remote sensing reflectance and diffuse attenuation coefficient. The working hypothesis was that over relatively large spatial and temporal scales, the vertical profiles of bio-optical properties were predictable. The specific technical objectives were: (1) To characterize the vertical distribution of the inherent and apparent optical properties by measuring downwelling and upwelling irradiances, upwelling radiances, scalar irradiance of PAR, and beam transmissions at each station - from these data, spectral diffuse attenuation coefficients, irradiance reflectances, remote sensing reflectances, surface-leaving radiances and beam attenuation coefficients were determined; (2) To characterize the spectral absorption of total particulate, detrital, and dissolved organic material at each station from discrete water samples; (3) To describe the vertical distribution of photoadaptive properties in the water column by measuring profiles of stimulated (SF) and natural (NF) fluorescence and examining relationships between SF and NF as a function of diffuse optical depth, pigment biomass and primary productivity; and (4) To establish locally derived, in-water algorithms relating remote sensing reflectance spectra to diffuse attenuation coefficients, phytoplankton pigment concentrations and primary productivity, through intercomparisons with in situ measurements, for application to SeaWiFS data. Trees, Charles C. Unspecified Center NASA-CR-205485, NAS 1.26:205485, CHORS-...
Download or read book Ocean Optics Protocols for Satellite Ocean Color Sensor Validation Revision 4 written by and published by . This book was released on 2003 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Real time Coastal Observing Systems for Marine Ecosystem Dynamics and Harmful Algal Blooms written by Babin, Marcel and published by UNESCO. This book was released on 2008-06-05 with total page 880 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proliferation of harmful phytoplankton in marine ecosystems can cause massive fish kills, contaminate seafood with toxins, impact local and regional economies and dramatically affect ecological balance. Real-time observations are essential for effective short-term operational forecasting, but observation and modelling systems are still being developed. This volume provides guidance for developing real-time and near real-time sensing systems for observing and predicting plankton dynamics, including harmful algal blooms, in coastal waters. The underlying theory is explained and current trends in research and monitoring are discussed.Topics covered include: coastal ecosystems and dynamics of harmful algal blooms; theory and practical applications of in situ and remotely sensed optical detection of microalgal distributions and composition; theory and practical applications of in situ biological and chemical sensors for targeted species and toxin detection; integrated observing systems and platforms for detection; diagnostic and predictive modelling of ecosystems and harmful algal blooms, including data assimilation techniques; observational needs for the public and government; and future directions for research and operations.
Download or read book Ocean Inherent Optical Property Estimation from Irradiances written by and published by . This book was released on 1997 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method is evaluated for estimating the absorption coefficient a and the backscattering coefficient beta(sub beta) from measurements of the upward and downward irradiances Epsilon sub mu(z) and Epsilon sub d(z). With this method, the reflectance ratio R(z) and the downward diffuse attenuation coefficient Kappa sub d(z) obtained from Epsilon sub mu(z) and Epsilon sub d(z) are used to estimate the inherent optical properties R(sub infinity) and Kappa (sub infinity) that are the asymptotic values of R(sub infinity) and Kappa (sub infinity), respectively. For an assumed scattering phase function Beta, there are unique correlations between the values of R(sub infinity) and Kappa(infinity) and those of alpha and beta(sub beta) that can be derived from the radiative transfer equation. Good estimates of alpha and the Gordon parameter G = beta(sub beta)/(alpha + beta (sub beta)) can be obtained from R(infinity) and Kappa(sub infinity) if the true scattering phase function is not greatly different from the assumed function. The method works best in deep, homogeneous waters, but can be applied to some cases of stratified waters. To improve performance in shallow waters where bottom effects are important, the deep- and shallowmeasurement reflectance models also are developed.
Download or read book Ocean Optical Modeling Light Field Structure Internal Radiant Emission and Vertical Inhomogeneities written by and published by . This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall goals of this project are the determination of the most significant optical parameters needed for the modeling and prediction of the penetration and second-order reemission of light in the sea. This problem is confounded by the multiple scattering of the penetrating and secondarily emitted photons. This multiple scattering phenomenon creates non-linearities in the submarine photic field which dictates that the most efficient approach to solve the problem is the Monte Carlo simulation of photon penetration. I have been developing code for Monte Carlo simulations of photon penetration and an exciting development is the porting of this code to the Cray Y-MP supercomputer. I have been given computer time for this development at the North Carolina Supercomputer Center, and I have also done development on the Primary Oceanographic Prediction System (POPS) at the Cray Y-MP of the U.S. Naval Oceanographic Office, Stennis Space Center, Bay St. Louis, MS. In the short term the operational limits for the optical parameters used to characterize the light climate for the open ocean will be established. These limits on the parameters that can be conveniently measured (apparent optical properties) will be determined from the Monte Carlo simulations employing the inherent optical properties. That is, the apparent optical properties can be derived from the Monte Carlo simulations using the inherent optical properties. Thus, reliable links will be established between the easily measured apparent optical properties and the more difficult inherent optical properties. The end result of this effort connecting the inherent and apparent optical properties will be a robust and reliable 'standard ocean model'.
Download or read book Physical Optics of Ocean Water written by K.S. Shifrin and published by Springer Science & Business Media. This book was released on 1998-02-18 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical Dependence of the Near asymptotic Apparent Optical Properties on the Inherent Optical Properties of Sea Water written by George F. Beardsley and published by . This book was released on 1969 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Uniqueness in Remote Sensing of the Inherent Optical Properties of Ocean Water written by and published by . This book was released on 2004 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study examines the problem of uniqueness in the relationship between the remote-sensing reflectance (Rrs) and the inherent optical properties (IOPs) of ocean water. The results show that diffuse reflectance of plane irradiance from ocean water is inherently ambiguous. Furthermore, in the 400
Download or read book Scale Closure in Upper Ocean Optical Properties written by Rebecca Erin Green and published by . This book was released on 2002 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) The role of seawater constituents in determining remote sensing reflectance, Rrs, was determined using radiative transfer theory. Seasonal differences in the spectral shape of Rrs were contributed to approximately equally by eukaryotic phytoplankton absorption, dissolved absorption, and non-phytoplankton bb. A higher inverse wavelength dependence of non-phytoplankton bb in the summer was caused by the contribution of small detritus, in contrast to larger minerals in the spring. Measurements of bb and Rrs were compared to values from bio-optical models based on chlorophyll concentration. Differences in measured and modeled bb and Rrs were caused by higher dissolved absorption and higher backscattering efficiencies and scattering by non-phytoplankton than were assumed by the model.
Download or read book Bathymetry from Hyperspectral Sensors A Preliminary Analysis of the Problem written by and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water depth, bottom reflectance, inherent optical properties of the water column (scattering, absorption, and fluorescence), and illumination conditions combine to determine the upwelling spectral radiance of coastal waters. If these complex optical relationships could be quantified, it would be possible to extract coastal information from spectral radiance data. We use data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) to begin to characterize these relationships as a first step toward development of algorithms for retrieval of water depth from hyperspectral imagery. Data are analyzed for two areas: the western coast of Florida in the Tampa Bay area and the Florida Keys between Upper Matecumbe and Plantation Keys. A neural network approach has been used to demonstrate retrieval of reasonable depths from spectral radiance over a depth range of 0 to 6 m. The ability of the neural network to generalize, producing algorithms with some degree of universality among diverse coastal environments, has been investigated in a preliminary fashion.
Download or read book Retieval of Inherent Optical Properties from Reflectance Spectra in Oceanic and Coastal Waters with Neural Network Modeling written by Ioannis Ioannou and published by . This book was released on 2011 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction written by Rudolph W. Preisendorfer and published by . This book was released on 1976 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
