An Improved Understanding of Aerosol Processes Using Satellite Observations of Aerosol Optical Properties PDF Download

Author: Claire Elizabeth Bulgin
Publisher:
ISBN:
Category :
Languages : en
Pages : 107

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Author: Tanvir Islam
Publisher: Elsevier
ISBN: 0128104384
Category : Science
Languages : en
Pages : 366

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Book Description
Remote Sensing of Aerosols, Clouds, and Precipitation compiles recent advances in aerosol, cloud, and precipitation remote sensing from new satellite observations. The book examines a wide range of measurements from microwave (both active and passive), visible, and infrared portions of the spectrum. Contributors are experts conducting state-of-the-art research in atmospheric remote sensing using space, airborne, and ground-based datasets, focusing on supporting earth observation satellite missions for aerosol, cloud, and precipitation studies. A handy reference for scientists working in remote sensing, earth science, electromagnetics, climate physics, and space engineering. Valuable for operational forecasters, meteorologists, geospatial experts, modelers, and policymakers alike. Presents new approaches in the field, along with further research opportunities, based on the latest satellite data Focuses on how remote sensing systems can be designed/developed to solve outstanding problems in earth and atmospheric sciences Edited by a dynamic team of editors with a mixture of highly skilled and qualified authors offering world-leading expertise in the field

Author: Alexander A. Kokhanovsky
Publisher: Springer
ISBN: 9783540693963
Category : Science
Languages : en
Pages : 388

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Book Description
Aerosols have a significant influence on the Earth's radiation budget, but there is considerable uncertainty about the magnitude of their effect on the Earth's climate. Currently, satellite remote sensing is being increasingly utilized to improve our understanding of the effect of atmospheric aerosols on the climate system. Satellite Aerosol Remote Sensing Over Land is the only book that brings together in one volume the most up-to-date research and advances in this discipline. As well as describing the current academic theory, the book presents practical applications, utilizing state-of-the-art instrumentation, invaluable to the work of environmental scientists. With contributions by an international group of experts and leaders of correspondent aerosol retrieval groups, the book is an essential tool for all those working in the field of climate change.

Author: Yueqing Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 182

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Book Description
Atmospheric aerosols are solid particles and liquid droplets that are usually smaller than the diameter of a human hair. They can be found drifting in the air in every ecosystem on Earth, leaving significant impacts on human health and our climate. Understanding the spatial and temporal distribution of different atmospheric aerosols, therefore, is an important first step to decode the complex system of aerosols and further, their effects on public health and climate. The development of remote-sensing radiometers provides a powerful tool to monitor the amount of atmospheric aerosols, as well as their compositions. Radiometers aboard satellites measure the amount of electromagnetic solar radiation. The amount of atmospheric aerosols is further quantified by aerosol optical depth (AOD), defined as the amount of solar radiation that aerosols scatter and absorb in the atmosphere and generally prevent from reaching the Earth surface. Despite efforts to improve remote-sensing instruments and a great demand for a detailed profile of aerosol spatial distribution, methods needed to provide AOD estimation at a reasonably fine resolution, are lacking. The quantitative uncertainties in the amount of aerosols, and especially aerosol compositions, limit the utility of traditional methods for aerosol retrieval at a fine resolution. In Chapter 2 and 3 of this thesis, we exploit the use of statistical methods to estimate aerosol optical depth using remote-sensed radiation. A Bayesian hierarchy proves to be useful for modeling the complicated interactions among aerosols of different amount and compositions over a large spatial area. Based on the hierarchical model, Chapter 2 estimates and validates aerosol optical depth using Markov chain Monte Carlo methods, while chapter 3 resorts to an optimization-based approach for faster computation. We extend our study focus from the aerosol amount to the aerosol compositions in Chapter 4. Chapter 1 briefly reviews the characteristics of atmospheric aerosols, including the different types of aerosols and their major impacts on human health. We also introduce a major remote-sensing instrument, NASA's Multi-angle Imaging SpectroRadiometer (MISR), which collects the observations our studies base on. Currently, the MISR operational aerosol retrieval algorithm provides estimates of aerosol optical depth at the spatial resolution of 17.6 km. In Chapter 2, we embed MISR's operational weighted least squares criterion and its forward calculations for aerosol optical depth retrievals in a likelihood framework. We further expand it into a hierarchical Bayesian model to adapt to finer spatial resolution of 4.4 km. To take advantage of the spatial smoothness of aerosol optical depth, our method borrows strength from data at neighboring areas by postulating a Gaussian Markov Random Field prior for aerosol optical depth. Our model considers aerosol optical depth and mixing vectors of different types of aerosols as continuous variables. The inference is then carried out using Metropolis-within-Gibbs sampling methods. Retrieval uncertainties are quantified by posterior variabilities. We also develop a parallel Markov chain Monte Carlo algorithm to improve computational efficiency. We assess our retrieval performance using ground-based measurements from the AErosol RObotic NETwork (AERONET) and satellite images from Google Earth. Based on case studies in the greater Beijing area, China, we show that 4.4 km resolution can improve both the accuracy and coverage of remote-sensed aerosol retrievals, as well as our understanding of the spatial and seasonal behaviors of aerosols. This is particularly important during high-AOD events, which often indicate severe air pollution. Chapter 3 of this thesis continues to improve our statistical aerosol retrievals for better accuracy and more efficient computation by switching to an optimization-based approach. We first establish objective functions for aerosol optical depth and aerosol compositions, based upon MISR operational weighted least squares criterion and its forward calculations. Our method also borrows strength from aerosol spatial smoothness by constructing penalty terms in the objective functions. The penalties correspond to a Gaussian Markov Random Field prior for aerosol optical depth and a Dirichlet prior for aerosol mixing vectors under our hierarchical Bayesian scheme; the optimization-based approach corresponds to Bayesian Maximum a Posteriori (MAP) estimation. Our MAP retrieval algorithm provides computational efficiency almost 60 times that of our Bayesian retrieval algorithm presented in Chapter 2. To represent the increasing heterogeneity of urban aerosol sources, our model continues to expand the pre-fixed aerosol mixtures used in the MISR operational algorithm by considering aerosol mixing vectors as continuous variables. Our retrievals are again validated using ground-based AERONET measurements. Case studies in the greater Beijing and Zhengzhou areas of China reassure that 4.4 km resolution can improve the accuracy and spatial coverage of remotely-sensed retrievals and enhance our understanding of the spatial behaviors of aerosols. When comparing our aerosol retrievals to the extensive ground-based measurements collected in Baltimore, Maryland, we encountered greater uncertainties of aerosol compositions. It is a result from both the complex terrain structures of Baltimore and its various aerosol emission sources. Chapter 4, as result, extends the flexibility of our previous aerosol retrievals by incorporating a complete set of the eight commonly observed types of aerosols. The consequential rise in model complexity is met by a warm-start Markov chain Monte Carlo sampling scheme. We first design two Markov sub-chains, each representing an aerosol mixture containing only four types of the commonly observed aerosols. Combining the samples generated by these two sub-chains, we propose an initialization for the Markov chain that contains all eight types of commonly observed aerosols. Partial information on the interactions of different types of aerosols from the samples generated by the sub-chains proves to be useful in choosing a more efficient initial point for the complete Markov chain. Faster computation is achieved without compromising the retrieval accuracy nor the spatial resolution of the estimated aerosol optical depth. In the end, through case studies of aerosol retrievals for the Baltimore area, we explore the potentials of remote-sensed retrievals in improving our understanding of aerosol compositions.

Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309492432
Category : Science
Languages : en
Pages : 29

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Book Description
We live on a dynamic Earth shaped by both natural processes and the impacts of humans on their environment. It is in our collective interest to observe and understand our planet, and to predict future behavior to the extent possible, in order to effectively manage resources, successfully respond to threats from natural and human-induced environmental change, and capitalize on the opportunities â€" social, economic, security, and more â€" that such knowledge can bring. By continuously monitoring and exploring Earth, developing a deep understanding of its evolving behavior, and characterizing the processes that shape and reshape the environment in which we live, we not only advance knowledge and basic discovery about our planet, but we further develop the foundation upon which benefits to society are built. Thriving on Our Changing Planet: A Decadal Strategy for Earth Observation from Space (National Academies Press, 2018) provides detailed guidance on how relevant federal agencies can ensure that the United States receives the maximum benefit from its investments in Earth observations from space, while operating within realistic cost constraints. This short booklet, designed to be accessible to the general public, provides a summary of the key ideas and recommendations from the full decadal survey report.

Author: Ken S. Carslaw
Publisher: Elsevier
ISBN: 0128231726
Category : Science
Languages : en
Pages : 856

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Book Description
The ever-diversifying field of aerosol effects on climate is comprehensively presented here, describing the strong connection between fundamental research and model applications in a way that will allow both experienced researchers and those new to the field to gain an understanding of a wide range of topics. The material is consistently presented at three levels for each topic: (i) an accessible "quick read" of the essentials, (ii) a more detailed description, and (iii) a section dedicated to how the processes are handled in models. The modelling section in each chapter summarizes the current level of knowledge and what the gaps in this understanding mean for the effects of aerosols on climate, enabling readers to quickly understand how new research fits into established knowledge. Definitions, case studies, reference data, and examples are included throughout. Aerosols and Climate is a vital resource for graduate students, postdoctoral researchers, senior researchers, and lecturers in departments of atmospheric science, meteorology, engineering, and environment. It will also be of interest to those working in operational centers and policy-facing organizations, providing strong reference material on the current state of knowledge. Includes a section in each chapter that focuses on the treatment of relevant aerosol processes in climate models Provides clear exposition of the challenges in understanding and reducing persistent gaps in knowledge and uncertainties in the field of aerosol-climate interaction, going beyond the fundamentals and existing knowledge Authored by experts in modeling and aerosol processes, analysis or observations to ensure accessibility and balance

Author: Jacqueline Lenoble
Publisher: Springer Science & Business Media
ISBN: 3642177255
Category : Technology & Engineering
Languages : en
Pages : 423

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Book Description
This book gives a much needed explanation of the basic physical principles of radiative transfer and remote sensing, and presents all the instruments and retrieval algorithms in a homogenous manner. The editors provide, for the first time, an easy path from theory to practical algorithms in one easily accessible volume, making the connection between theoretical radiative transfer and individual practical solutions to retrieve aerosol information from remote sensing, and providing the specifics and intercomparison of all current and historical retrieval methods.

Author: Xueke Li
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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A good understanding of trends, variations, and causes of atmospheric aerosols is vital to quantifying the role of air quality in climate change and health concerns and for informing relevant regulatory policies. This thesis presents four projects that exploit a range of observational data and modeling tools to characterize and interpret aerosol dynamics and its potential determinates. An econometric model is implemented to identify aerosol variations, predictions, and the driving forces using six sites spreading across North America and East Asia during 2003-2015. Regional differences caused by impacts of climatology and land cover types are observed. Statistical validation of time series ARIMA models indicates the applicability and feasibility of ARIMA modeling. The reasonably-predicted AOD values could provide reliable estimates to inform better the decision-making for sustainable environmental management and the initiative of reforestation on emission sinks could have potential implications for climate change mitigation. The time series analyses and modeling of aerosol variability are further investigated in a spatially continuous framework based on the valuable spatiotemporal dimension of the remote sensing data over the contiguous United States (U.S.) and China. By comparing variations and trends in these two countries, we attribute the large differences to the energy strategies, economic and urban development, and lifestyle activities. Areas most suitable for applying the model for prediction are those with high AOD quality, high completeness of AOD data, low-AOD values, and AOD time series with clear seasonal variations. Then, a geographically weighted regression (GWR) model is employed to estimate PM2.5 concentration and analyze its relationships with AOD, meteorological variables, and nighttime light (NTL) data across the Northeastern United States in 2013. Improved GWR model performance is found for the warm season when applying the index that incorporates normalized difference vegetation index (NDVI) into NTL (17% and 7.26% better than GWR model without NDVI and NTL data and GWR model without NTL data, respectively). The spatial distribution of the estimated PM2.5 levels clearly reveals patterns consistent with those densely populated areas and high traffic areas. Finally, an evaluation framework to identify both mean and extreme conditions of PM2.5 is proposed and applied to the WRF-CMAQ simulations over the contiguous U.S. for the period of 2001-2010. While the model exhibits satisfactory performance over the eastern U.S., PM2.5 mean variations and extreme trends in the western U.S. are not well represented partly due to the complex terrains and active fire activities. Moreover, the relationship between extreme PM2.5 pollution episodes and abnormal synoptic conditions is quantified. More extreme PM2.5 pollution episodes are expected in a warming climate, with rural stations and the western U.S. suffer the most.

Author: Alexander A. Kokhanovsky
Publisher: Springer Science & Business Media
ISBN: 3540693971
Category : Science
Languages : en
Pages : 398

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Book Description
Aerosols have a significant influence on the Earth's radiation budget, but there is considerable uncertainty about the magnitude of their effect on the Earth's climate. Currently, satellite remote sensing is being increasingly utilized to improve our understanding of the effect of atmospheric aerosols on the climate system. Satellite Aerosol Remote Sensing Over Land is the only book that brings together in one volume the most up-to-date research and advances in this discipline. As well as describing the current academic theory, the book presents practical applications, utilizing state-of-the-art instrumentation, invaluable to the work of environmental scientists. With contributions by an international group of experts and leaders of correspondent aerosol retrieval groups, the book is an essential tool for all those working in the field of climate change.

Author: Panel on Aerosol Radiative Forcing and Climate Change
Publisher: National Academies Press
ISBN: 0309588871
Category : Science
Languages : en
Pages : 180

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Book Description
This book recommends the initiation of an "integrated" research program to study the role of aerosols in the predicted global climate change. Current understanding suggest that, even now, aerosols, primarily from anthropogenic sources, may be reducing the rate of warming caused by greenhouse gas emissions. In addition to specific research recommendations, this book forcefully argues for two kinds of research program integration: integration of the individual laboratory, field, and theoretical research activities and an integrated management structure that involves all of the concerned federal agencies.