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Author: Guangming Zheng
Publisher:
ISBN: 9781303001406
Category :
Languages : en
Pages : 203
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Book Description
Partitioning of the total non-water absorption coefficient of seawater, anw(lambda), into phytoplankton, aph(lambda), and non-phytoplankton, adg(lambda), components is important to research in ocean optics, biology, and biogeochemistry. I developed a partitioning model based on stacked-constraints approach, which requires weakly restrictive assumptions about the spectral slope of adg(lambda) and the spectral shape of aph(lambda). With a comprehensive set of inequality constraints, the model first derives a wide range of speculative solutions for adg(lambda) and aph(lambda) and then identifies feasible solutions. Final model outputs include the optimal solutions that agree well with measurements (with biases typically within ±5%), and a range of feasible solutions that encompasses the measured adg(lambda) and aph(lambda) with a probability> 90% at most wavelengths. I also developed another model for partitioning the spectral absorption coefficient of suspended marine particles, ap(lambda), into phytoplankton, aph(lambda), and non-algal, ad(lambda), components based on the stacked-constraints approach. Partitioning results of the model generally agree well with measurements and are superior in terms of error statistics compared with previous partitioning models. These results support the prospect for the applications of the partitioning models using the input data of anw(lambda) and ap(lambda) collected from various oceanographic and remote-sensing platforms. I also evaluated the performance of the Quasi-Analytical Algorithm (QAA) for deriving the spectral total absorption, a(lambda), and backscattering, bb(lambda), coefficients of seawater from input spectrum of remote-sensing reflectance, Rrs(lambda), using field data collected in the Arctic and lower-latitude open waters. The performance of QAA for estimating a(lambda) varies from very good to fair (bias on the order of ±10%) depending on light wavelength and the oceanic region. For bb(lambda), the QAA typically shows overestimation from small to as large as about 35%. A sensitivity analysis shows that the parameter u [-̲bb/(a+bb)] at the reference wavelength of 555 nm generally contributes the most significant bias to bb(lambda) at all wavelengths within the spectrum of visible light, whereas the interplay between u(555) and u(lambda) generally dominates the errors of QAA-derived a(lambda) except for the reference wavelength. Our findings provide guidance for future efforts towards refinement of the QAA and potentially also development of other inverse models.
Author: Guangming Zheng
Publisher:
ISBN: 9781303001406
Category :
Languages : en
Pages : 203
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Book Description
Partitioning of the total non-water absorption coefficient of seawater, anw(lambda), into phytoplankton, aph(lambda), and non-phytoplankton, adg(lambda), components is important to research in ocean optics, biology, and biogeochemistry. I developed a partitioning model based on stacked-constraints approach, which requires weakly restrictive assumptions about the spectral slope of adg(lambda) and the spectral shape of aph(lambda). With a comprehensive set of inequality constraints, the model first derives a wide range of speculative solutions for adg(lambda) and aph(lambda) and then identifies feasible solutions. Final model outputs include the optimal solutions that agree well with measurements (with biases typically within ±5%), and a range of feasible solutions that encompasses the measured adg(lambda) and aph(lambda) with a probability> 90% at most wavelengths. I also developed another model for partitioning the spectral absorption coefficient of suspended marine particles, ap(lambda), into phytoplankton, aph(lambda), and non-algal, ad(lambda), components based on the stacked-constraints approach. Partitioning results of the model generally agree well with measurements and are superior in terms of error statistics compared with previous partitioning models. These results support the prospect for the applications of the partitioning models using the input data of anw(lambda) and ap(lambda) collected from various oceanographic and remote-sensing platforms. I also evaluated the performance of the Quasi-Analytical Algorithm (QAA) for deriving the spectral total absorption, a(lambda), and backscattering, bb(lambda), coefficients of seawater from input spectrum of remote-sensing reflectance, Rrs(lambda), using field data collected in the Arctic and lower-latitude open waters. The performance of QAA for estimating a(lambda) varies from very good to fair (bias on the order of ±10%) depending on light wavelength and the oceanic region. For bb(lambda), the QAA typically shows overestimation from small to as large as about 35%. A sensitivity analysis shows that the parameter u [-̲bb/(a+bb)] at the reference wavelength of 555 nm generally contributes the most significant bias to bb(lambda) at all wavelengths within the spectrum of visible light, whereas the interplay between u(555) and u(lambda) generally dominates the errors of QAA-derived a(lambda) except for the reference wavelength. Our findings provide guidance for future efforts towards refinement of the QAA and potentially also development of other inverse models.
Author: James L. Mueller
Publisher:
ISBN:
Category : Colors
Languages : en
Pages : 524
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Book Description
Author: Bogdian Wozniak
Publisher: Springer Science & Business Media
ISBN: 0387495606
Category : Science
Languages : en
Pages : 463
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Book Description
This book provides a detailed description of light absorption and absorbents in seawaters with respect to provenance, region of the sea, depth of the occurrence and trophicity. The text is based on a substantial body of contemporary research results taken from the subject literature (over 400 references) and the work of the authors over a period of 30 years.
Author:
Publisher:
ISBN:
Category : Chlorophyll
Languages : en
Pages : 132
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Book Description
Author: Babin, Marcel
Publisher: UNESCO
ISBN: 9231040421
Category : Nature
Languages : en
Pages : 880
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Book Description
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.
Author: Dale A. Kiefer
Publisher:
ISBN:
Category :
Languages : en
Pages : 4
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Book Description
Our long term goal is to understand the biological and optical properties of the planktonic community of the open ocean and to derive mathematical descriptions of this community. We pursue our research goal largely by analyzing bio-optical signals measured in the field and by comparing these signals with the predictions of mathematical models. During this work we developed a macrophotometric technique for measuring the absorption of light by suspended microparticles in sea water. We also developed in collaboration with R. Iturriaga a technique for measuring the absorption efficiency factor for individuals cells. During the 4 Biowatt cruises in 1987, we made over 500 measurements of the spectral absorption coefficient of suspended microparticles and developed a statistical technique for determining the contribution by phytoplankton to this coefficient. In addition, we completed a microphotometric analysis of spectral light absorption efficiency by individual particles collected during the Biowatt I cruise. In 1988 we continued our analysis of variability in the spectral absorption coefficient of microparticles in the western Sargasso Sea. (jes).
Author: N.G. Jerlov
Publisher: Elsevier
ISBN: 0080870503
Category : Science
Languages : en
Pages : 247
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Book Description
Marine Optics
Author: Simon Jungblut
Publisher: Springer
ISBN: 3319932845
Category : Science
Languages : en
Pages : 251
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Book Description
This open access book presents the proceedings volume of the YOUMARES 8 conference, which took place in Kiel, Germany, in September 2017, supported by the German Association for Marine Sciences (DGM). The YOUMARES conference series is entirely bottom-up organized by and for YOUng MARine RESearchers. Qualified early career scientists moderated the scientific sessions during the conference and provided literature reviews on aspects of their research field. These reviews and the presenters’ conference abstracts are compiled here. Thus, this book discusses highly topical fields of marine research and aims to act as a source of knowledge and inspiration for further reading and research.
Author: Victor Martinez-Vicente
Publisher: Frontiers Media SA
ISBN: 2889634213
Category :
Languages : en
Pages : 403
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Book Description
CLEO publications in Frontiers in Marine Science Foreword Josef Aschbacher, Director of ESA’s Earth Observation Programmes Satellite data have drastically changed the view we have of the oceans. Covering about 70% of Earth’s surface, oceans play a unique role for our planet and for our life – but large areas remain unexplored and are difficult to reach. Since the 1980s, Earth-orbiting satellites have helped to observe what is happening at the ocean surface. Sensors like CZCS, AVHRR, SeaWifs and MODIS provided the first ocean colour data from space. Starting in 2002, ESA's Medium Resolution Imaging Spectrometer (MERIS) on-board the environmental satellite Envisat, provided detailed information on phytoplankton biomass and concentrations of other matter in the global oceans. These satellite observations laid the groundwork for studying the marine environment and how it responds to climate change, and the research community has since delivered information on the variability of marine ecosystems. Part of this work is reflected in this stunning collection of peer-reviewed publications presented at the workshop, Colour and Light in the Ocean from Earth Observation (CLEO), held at ESA’s ESRIN site in Frascati, Italy, on 6–8 September 2016. The event attracted more than 160 participants from all over the world, including remote sensing experts, marine ecosystem modelers, in-situ observers and users of Earth observation data. Scientifically, the meeting covered applications in climate studies over primary productivity and ocean dynamics, to pools of carbon and phytoplankton diversity at global and regional scales. It also demonstrated the potential of Earth observation and its contribution to modern oceanography. Looking to the future, new satellites developed by ESA under the coordination of the European Commission will further our scientific and operational observations of the seas. With Sentinel-3A in orbit and its twin Sentinel-3B following in 2017, there is a new category of data available for operational oceanographic applications and climate studies for years to come. These data are free and easy to access by anyone interested. Looking at the role of oceans in our daily lives, I am sure that this collection of scientific excellence will be valued by scientists of today and will inspire the next generation to carry these ideas into the future.
Author: Derric G. Tay
Publisher:
ISBN:
Category :
Languages : en
Pages : 48
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Book Description
In order to investigate the possibility of using oceanic visual spectrum data (i.e., ocean color) to differentiate between phytoplankton cell types, a simple mathematical model of light absorption was constructed in MATLAB, in order to investigate the effects of depth, cell size, and water on light absorption by a layer of water containing suspended particles. The model takes chlorophyll a absorption data, cell diameter, intracellular and bulk concentrations of chlorophyll a, pure water absorption data, and thickness of water layer as inputs, and outputs the attenuation by absorption of light that shines through a layer of water containing suspended, absorbing cells. Plots of absorptive attenuation were made, varying thickness, cell diameter, and inclusion of water absorption. These plots were qualitatively analyzed. It was found that water greatly dominates absorption, when included. This finding suggests that using visual data may be difficult with ocean water, though scattering effects remain to be accounted for, and thus this problem warrants further study.