Modeling of Chemical Transformations of SOxand NOx in the Polluted Atmosphere — An Overview of Approaches and Current Status

1985 ◽  
pp. 163-192
Author(s):  
N. V. Gillani
Keyword(s):  
Current Status ◽  
Chemical Transformations ◽  
Polluted Atmosphere

scholarly journals Data assimilation in atmospheric chemistry models: current status and future prospects for coupled chemistry meteorology models

2014 ◽  
Vol 14 (23) ◽  
pp. 32233-32323 ◽  
Author(s):  
M. Bocquet ◽  
H. Elbern ◽  
H. Eskes ◽  
M. Hirtl ◽  
R. Žabkar ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Atmospheric Chemistry ◽  
Hybrid Methods ◽  
Model Performance ◽  
Chemical Data ◽  
Current Status ◽  
Model Parameters ◽  
Chemical Transformations ◽  
Future Prospects ◽  
Main Challenge

Abstract. Data assimilation is used in atmospheric chemistry models to improve air quality forecasts, construct re-analyses of three-dimensional chemical (including aerosol) concentrations and perform inverse modeling of input variables or model parameters (e.g., emissions). Coupled chemistry meteorology models (CCMM) are atmospheric chemistry models that simulate meteorological processes and chemical transformations jointly. They offer the possibility to assimilate both meteorological and chemical data; however, because CCMM are fairly recent, data assimilation in CCMM has been limited to date. We review here the current status of data assimilation in atmospheric chemistry models with a particular focus on future prospects for data assimilation in CCMM. We first review the methods available for data assimilation in atmospheric models, including variational methods, ensemble Kalman filters, and hybrid methods. Next, we review past applications that have included chemical data assimilation in chemical transport models (CTM) and in CCMM. Observational data sets available for chemical data assimilation are described, including surface data, surface-based remote sensing, airborne data, and satellite data. Several case studies of chemical data assimilation in CCMM are presented to highlight the benefits obtained by assimilating chemical data in CCMM. A case study of data assimilation to constrain emissions is also presented. There are few examples to date of joint meteorological and chemical data assimilation in CCMM and potential difficulties associated with data assimilation in CCMM are discussed. As the number of variables being assimilated increases, it is essential to characterize correctly the errors; in particular, the specification of error cross-correlations may be problematic. In some cases, offline diagnostics are necessary to ensure that data assimilation can truly improve model performance. However, the main challenge is likely to be the paucity of chemical data available for assimilation in CCMM.

Preface

2000 ◽  
Vol 72 (7) ◽  
pp. v ◽  
Author(s):  
James R. Bull
Keyword(s):  
Quality Of Life ◽  
Green Chemistry ◽  
Organic Synthesis ◽  
Chemical Industry ◽  
Working Party ◽  
Sustainable Growth ◽  
Environmentally Benign ◽  
Current Status ◽  
Chemical Transformations

The evolving face of contemporary chemistry is characterized by unprecedented societal demand for the goods and services of the chemical industry, tempered by growing awareness that finite resources must be conserved and their exploitation optimized. At the same time, environmental protection has become a global concern, and the chemical industry is increasingly obliged to reexamine conventional methodologies, and to seek ways of developing and applying more efficient and environmentally benign strategies for future sustainable growth. The tandem concepts of discovery and exploitation are obviously as old as the industry itself, but there is new urgency in the quest for solutions that will halt and reverse some of the negative effects of historical development and, at the same time, seize the opportunities offered by the extraordinary advances in chemical sciences during recent years.The twin challenges of increasing synthetic efficiency in chemical transformations, and minimizing environmentally hostile waste offer irresistible opportunities for new-age ingenuity. It is in this climate that new approaches to these problems have coalesced into a distinctive discipline, which has been variously described and named but has, as its central thrust, the strategic objectives of increased efficiency, sustainability, and, ultimately, societal benefit. These objectives identify closely with the vision of IUPAC, which is eloquently expressed in two of the goals defined in the current strategic plan, namely to contribute to the advancement of research in the chemical sciences throughout the world and to assist chemistry-related industry in its contributions to sustainable development, wealth creation, and the improvement of the quality of life.A Working Party on Synthetic Pathways and Processes in Green Chemistry was established in 1996, under the auspices of the Commission on Physical Organic Chemistry (Commission III.2) of the IUPAC Organic and Biomolecular Division, with a mandate to promote and disseminate awareness of environmentally compatible synthetic pathways (green chemistry), throughout the academic and industrial scientific research community. In 1999 this group, in close collaboration with the IUPAC Subcommittee on Organic Synthesis, initiated a project to publish a Symposium-in-Print on Green Chemistry, and undertook to compile a collection of expert reviews on aspects of the topic, underpinned by an introductory account of the evolution of the project, its rationale, and its interfaces with complementary initiatives and organisations.This volume represents the culmination of that undertaking, and the introductory overview, comprising contributions by members of the Working Party, gives a detailed account of the role and interest of IUPAC in promoting this initiative, and sets the scene for the ensuing Symposium-in-Print, with an interpretation of the meaning of the term "green chemistry" and an account of the historical emergence of the concept. This is followed by a synoptic preamble, in which the content and purpose of individual reviews in the Symposium-in-Print are summarized. Although the preamble adopts a sequence of presentation based upon the logic imposed by the title theme of synthetic pathways and processes, the influential role of the Organization for Economic Cooperation and Development (OECD) is recognized by adoption of their recommended delineation of topics for grouping the ensuing reviews. The Symposium-in-Print sets out to capture the current status of the discipline and to project the boundless opportunities and challenges confronting contemporary organic synthesis and its practice in a changing world, increasingly sensitized to the finite bounds of natural resources and the vulnerability of the biosphere. It offers evidence that current problems are being addressed and can be solved, and engenders expectations that future problems can be anticipated and prevented. Most importantly, the collective expertise and commitment of the contributors is expected to furnish inspirational guidance to practicing scientists and students of chemistry, to participate in shaping a more environmentally benign future, in which the synthetic pathways and processes in chemistry are fully reconciled with societal expectations for ever-improving quality of life.J. R. BullIUPAC Special Topics Editor

scholarly journals Data assimilation in atmospheric chemistry models: current status and future prospects for coupled chemistry meteorology models

2015 ◽  
Vol 15 (10) ◽  
pp. 5325-5358 ◽  
Author(s):  
M. Bocquet ◽  
H. Elbern ◽  
H. Eskes ◽  
M. Hirtl ◽  
R. Žabkar ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Atmospheric Chemistry ◽  
Hybrid Methods ◽  
Model Performance ◽  
Chemical Data ◽  
Current Status ◽  
Model Parameters ◽  
Chemical Transformations ◽  
Future Prospects ◽  
Main Challenge

Abstract. Data assimilation is used in atmospheric chemistry models to improve air quality forecasts, construct re-analyses of three-dimensional chemical (including aerosol) concentrations and perform inverse modeling of input variables or model parameters (e.g., emissions). Coupled chemistry meteorology models (CCMM) are atmospheric chemistry models that simulate meteorological processes and chemical transformations jointly. They offer the possibility to assimilate both meteorological and chemical data; however, because CCMM are fairly recent, data assimilation in CCMM has been limited to date. We review here the current status of data assimilation in atmospheric chemistry models with a particular focus on future prospects for data assimilation in CCMM. We first review the methods available for data assimilation in atmospheric models, including variational methods, ensemble Kalman filters, and hybrid methods. Next, we review past applications that have included chemical data assimilation in chemical transport models (CTM) and in CCMM. Observational data sets available for chemical data assimilation are described, including surface data, surface-based remote sensing, airborne data, and satellite data. Several case studies of chemical data assimilation in CCMM are presented to highlight the benefits obtained by assimilating chemical data in CCMM. A case study of data assimilation to constrain emissions is also presented. There are few examples to date of joint meteorological and chemical data assimilation in CCMM and potential difficulties associated with data assimilation in CCMM are discussed. As the number of variables being assimilated increases, it is essential to characterize correctly the errors; in particular, the specification of error cross-correlations may be problematic. In some cases, offline diagnostics are necessary to ensure that data assimilation can truly improve model performance. However, the main challenge is likely to be the paucity of chemical data available for assimilation in CCMM.

Current status of special planetary and lunar theories and ephemerides

1966 ◽  
Vol 25 ◽  
pp. 266-267
Author(s):  
R. L. Duncombe
Keyword(s):  
Observational Data ◽  
Current Status ◽  
Numerical Errors

An examination of some specialized lunar and planetary ephemerides has revealed inconsistencies in the adopted planetary masses, the presence of non-gravitational terms, and some outright numerical errors. They should be considered of temporary usefulness only, subject to subsequent amendment as required for the interpretation of observational data.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

Electron-deficient boron-based catalysts for C–H bond functionalisation

2021 ◽  
Author(s):  
Yuanhong Ma ◽  
Shao-Jie Lou ◽  
Zhaomin Hou
Keyword(s):  
Review Article ◽  
Current Status ◽  
Comprehensive Overview

This review article provides a comprehensive overview to recognise the current status of electron-deficient boron-based catalysis in C–H functionalisations.

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