Download or read book Oxygen Isotopic Studies of Atmospheric Nitrous Oxide written by Steven Scott Cliff and published by . This book was released on 1998 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stable Isotope Investigations of Atmospheric Nitrous Oxide written by Jan Kaiser and published by . This book was released on 2003 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of a Spectroscopic Technique for Continuous Online Monitoring of Oxygen and Site specific Nitrogen Isotopic Composition of Atmospheric Nitrous Oxide written by Eliza Harris and published by . This book was released on 2014 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrous oxide is an important greenhouse gas and ozone-depleting-substance. Its sources are diffuse and poorly characterized, complicating efforts to understand anthropogenic impacts and develop mitigation policies. Online, spectroscopic analysis of N2O isotopic composition can provide continuous measurements at high time resolution, giving new insight into N2O sources, sinks, and chemistry. We present a new preconcentration unit, "Stheno II," coupled to a tunable infrared laser direct absorption spectroscopy (TILDAS) instrument, to measure ambient-level variations in 18O and site-specific 15N N2O isotopic composition at remote sites with a temporal resolution of

Download or read book Stable Isotope Investigations of Atmospheric Nitrous Oxide written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: AbstractThe analysis of isotope ratios is of increasing importance to study the sources and sinks of atmospheric trace gases and to investigate their chemical reaction pathways. Nitrous oxide (N2O) has four mono-substituted rare isotopic species: 14N15N16O, 15N14N16O, 14N217O and 14N218O. Mass-spectrometric measurement techniques have been developed during the work described here which enable a complete characterisation of abundance variations of these species. The hitherto most comprehensive account of these variations in the troposphere and stratosphere is given and interpreted in detail with reference to a suite of laboratory experiments. The laboratory experiments represent a major part of this thesis and focus on the isotopic fractionation of N2O in its stratospheric sink reactions, i.e. ultraviolet photolysis and reaction with electronically excited oxygen atoms, O(1D). These processes are of dominant influence for the isotopic composition of atmospheric N2O. Parameters of potential importance such as temperature and pressure variations as well as wavelength changes in case of UV photolysis were considered. Photolysis at stratospherically relevant wavelengths> 190 nm invariably showed enrichments in 15N at both nitrogen atoms of the residual N2O as well as in 17O and 18O. Enrichments were significantly larger for the central N atom than for the terminal N (with intermediate values for 18O) and increased towards longer wavelengths and colder temperatures. For the first time, isotopic depletions were noted for 18O and 15N at the terminal nitrogen site in N2O photolysis at 185 nm. In contrast, the second important N2O sink, reaction with O(1D), causes comparatively smaller isotopic enrichments in stratospheric N2O. However, its position-dependent fractionation pattern is directly opposite to the one in photolysis corresponding to larger enrichments at the terminal N atom. Hence, both sink processes leave distinct isotope signatures in stratospheric N2O. Further N.

Download or read book Determination by Isotope Ratio Mass Spectrometry of the Absolute Isotope Amount Fractions of Oxygen and Nitrogen in Nitrous Oxide written by and published by . This book was released on 2007 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The significant interest related to atmospheric Nitrous oxide as a greenhouse gas and as a tool to regulate the Ozone concentration is well-known and requires to define a precise budget in the atmosphere for this gas. Therefore, the isotopic measurements are proposed to become the necessary additional instrument to better quantify this budget. The lack of a real comparability tool for the disparate Nitrous oxide isotopic measurement done required to start the work related to the development of a Reference material for Nitrogen and Oxygen in this gas. A measurement procedure for the complete isotope characterization of atmospheric Nitrous oxide sample has been developed and applied to establish a first Reference material for this gas. The whole work has been based on the peculiar instrumental capabilities of "Avogadro" MAT 271IRMS. Additional hardware and software improvement has been done for this mass spectrometer to apply the proposed method.

Download or read book Measurements of N2O Isotopologues 15 N 14 NO 14 N 15 NO and N2 18 O written by Sunyoung Park and published by . This book was released on 2005 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stable Isotopes and Biosphere Atmosphere Interactions written by Lawrence B Flanagan and published by Elsevier. This book was released on 2004-12-15 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emerging multidisciplinary field of earth system science sets out to improve our understanding functioning ecosystems, at a global level across the entire planet. Stable Isotopes and Biosphere - Atmosphere Interactions looks to one of its most powerful tools — the application of stable isotope analyses — to understanding biosphere-atmosphere exchange of the greenhouse gases, and synthesizes much of the recent progress in this work. Stable Isotopes and Biosphere - Atmosphere Interactions describes recent progress in understanding the mechanisms, processes and applications of new techniques. It makes a significant contribution to the emerging, multidisciplinary study of the Earth as an interacting system. This book will be an important reference for students and researchers in biology, ecology, biogeochemistry, meteorology, and atmospheric science and will be invaluable for anyone with any interest in the future of the planet. Describes applications of new stable isotope techniques to the emerging fields of earth system science and global change Illustrates advances in scaling of physiological processes from leaf/soil to the global scale Contains state-of-the-art, critical reviews written by international researchers and experts

Download or read book The Chemistry and Vertical Distribution of the Oxides of Nitrogen in the Atmosphere written by Lewis Earl Miller and published by . This book was released on 1954 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Estimating Regional Nitrous Oxide Emissions Using Isotopic Ratio Observations and a Bayesian Inverse Framework written by Michael James McClellan and published by . This book was released on 2018 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric nitrous oxide (N2O) significantly impacts Earth's climate due to its dual role as an inert potent greenhouse gas in the troposphere and as a reactive source of ozone-destroying nitrogen oxides in the stratosphere. Global atmospheric concentrations of N2O, produced by natural and anthropogenic processes, continue to rise due to increases in emissions linked to human activity. The understanding of the impact of this gas is incomplete as there remain significant uncertainties in its global budget. The experiment described in this thesis, in which a global chemical transport model (MOZART-4), a fine-scale regional Lagrangian model (NAME), and new high-frequency atmospheric observations are combined, shows that uncertainty in N2O emissions estimates can be reduced in areas with continuous monitoring of N2O mole fraction and site-specific isotopic ratios. Due to unique heavy-atom (15N and 18O) isotopic substitutions made by different N2O sources, the measurement of N2O isotopic ratios in ambient air can help identify the distribution and magnitude of distinct sources. The new Stheno-TILDAS continuous wave laser spectroscopy instrument developed at MIT, recently installed at the Mace Head Atmospheric Research Station in western Ireland, can produce high-frequency timelines of atmospheric N2O isotopic ratios that can be compared to contemporaneous trends in correlative trace gas mole fractions and NAME-based statistical distributions of the origin of air sampled at the station. This combination leads to apportionment of the relative contribution from five major N2O sectors in the European region (agriculture, oceans, natural soils, industry, and biomass burning) plus well-mixed air transported from long distances to the atmospheric N2O measured at Mace Head. Bayesian inverse modeling methods that compare N2O mole fraction and isotopic ratio observations at Mace Head and at Diibendorf, Switzerland to simulated conditions produced using NAME and MOZART-4 lead to an optimized set of source-specific N2O emissions estimates in the NAME Europe domain. Notably, this inverse modeling experiment leads to a significant decrease in uncertainty in summertime emissions for the four largest sectors in Europe, and shows that industrial and agricultural N2O emissions in Europe are underestimated in inventories such as EDGAR v4.3.2. This experiment sets up future work that will be able to help constrain global estimates of N2O emissions once additional isotopic observations are made in other global locations and integrated into the NAME-MOZART inverse modeling framework described in this thesis.

Download or read book Enrichment of 15N and 18O in Stratospheric Nitrous Oxide written by Thomas A. Rahn and published by . This book was released on 1998 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantifying Pacific Ocean Nitrous Oxide Cycling Using Intramolecular Isotope Measurements and Modeling written by Colette LaMonica Kelly and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrous oxide is one of the lesser-known greenhouse gases, yet its potential to warm the environment, on a per-molecule basis, is immense. Marine nitrous oxide production is concentrated in and around oxygen deficient zones, whose steep redox gradients allow for overlapping microbial processes that produce nitrous oxide. But the rates of these processes, and their relative importance in contributing to hotspots of nitrous oxide production, remain uncertain. This dissertation uses the intramolecular nitrogen isotopes (or isotopomers) of nitrous oxide to quantify its production in and around the eastern tropical North Pacific oxygen deficient zone. In Chapter 1, I find that high, near surface accumulations of nitrous oxide in this region are produced mainly by denitrification, with a smaller contribution from nitrification. In some core anoxic depths of the oxygen deficient zone, nitrous oxide cycling is not in steady state, while elsewhere, the isotopic content of nitrous oxide can be explained by denitrification with a positive site preference. In Chapter 2, I present a software package for isotopomer data processing and discuss the performance of this software. Ammonia-oxidizing archaea can produce nitrous oxide via a hybrid mechanism, so-called because it combines nitrogen derived from ammonium and nitrite to form nitrous oxide. In Chapter 3, I show that hybrid nitrous oxide production is inhibited by oxygen and reaches high yields at oxic-anoxic interfaces where ammonia oxidation is active. Integrating the information learned from these biogeochemical measurements, Chapter 4 presents a 1D advection-diffusion-reaction model constrained with nitrous oxide isotopomers to quantify nitrous oxide cycling in the eastern tropical North Pacific and test the sensitivity of that cycling to ocean deoxygenation and changes in organic matter export. Together, the results described in this dissertation show that nitrous oxide cycling in this region is a dynamic system that depends on low oxygen conditions and an organic matter source, conditions subject to change with ocean warming, deoxygenation, and increasing atmospheric N deposition. The constraints and parameters identified in this dissertation should provide a starting point for better implementations of nitrous oxide cycling in global biogeochemical models, making it possible to predict feedbacks between marine nitrous oxide cycling and climate change.

Download or read book Isotopic Characterisation of Atmospheric Nitrous Oxide by Fourier Transform Infrared Spectroscopy written by Federico Turatti and published by . This book was released on 2001 with total page 908 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nitrous Oxide and Climate Change written by Keith Smith and published by Earthscan. This book was released on 2010 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Nitrous oxide, N2O, is the third most important (in global warming terms) of the greenhouse gases, after carbon dioxide and methane. As this book describes, although it only comprises 320 parts per billion of the earth's atmosphere, it has a so-called Global Warming Potential nearly 300 times greater than that of carbon dioxide. N2O emissions are difficult to estimate, because they are predominantly biogenic in origin. The N2O is formed in soils and oceans throughout the world, by the microbial processes of nitrification and denitrification, that utilise the reactive N compounds ammonium and nitrate, respectively. These forms of nitrogen are released during the natural biogeochemical nitrogen cycle, but are also released by human activity. In fact, the quantity of these compounds entering the biosphere has virtually doubled since the beginning of the industrial age, and this increase has been matched by a corresponding increase in N2O emissions. The largest source is now agriculture, driven mainly by the use of synthetic nitrogen fertilisers. The other major diffuse source derives from release of NOx into the atmosphere from fossil fuel combustion and biomass burning, as well as ammonia from livestock manure. Some N2O also comes directly from combustion, and from two processes in the chemical industry: the production of nitric acid, and the production of adipic acid, used in nylon manufacture. Action is being taken to curb the industrial point-source emissions of N2O, but measures to limit or reduce agricultural emissions are inherently more difficult to devise. As we enter an era in which measures are being explored to reduce fossil fuel use and/or capture or sequester the CO2 emissions from the fuel, it is likely that the relative importance of N2O in the 'Kyoto basket' of greenhouse gases will increase, because comparable mitigation measures for N2O are inherently more difficult, and because expansion of the land area devoted to crops, to feed the increasing global population and to accommodate the current development of biofuels, is likely to lead to an increase in N fertiliser use, and thus N2O emission, worldwide. The aim of this book is to provide a synthesis of scientific information on the primary sources and sinks of nitrous oxide and an assessment of likely trends in atmospheric concentrations over the next century and the potential for mitigation measures"--Publisher's description.

Download or read book Nitrous Oxide N2O Isotopic Composition in the Troposphere written by Katherine Ellison Potter and published by . This book was released on 2011 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrous oxide (N2O) is a significant greenhouse gas and main contributor to stratospheric ozone destruction. Surface measurements of N2O mole fractions have been used to attribute source and sink strengths, but large uncertainties remain. Stable isotopic ratios of N2O (here considered 14N15N16O, 15N14N16O, 14N14N18O, relative to the abundant 14N14N16O) linked to source and sink isotopic signatures can provide additional constraints on emissions and counter-balancing stratospheric sink. However, the isotopic composition in the troposphere has been regarded and measured as a fixed value, limited by insufficient measurement precision and few data. This thesis provides the foundation for high-frequency, high-precision measurements and utilization of N2O tropospheric isotopic composition. This is achieved through the development of a new measuring capability with sufficient precision to detect the subtle signals of N2O isotopic composition in tropospheric air and uniquely fully-automated and high-frequency capable. This instrument was applied to produce the first set of tropospheric air observations gathered at a remote research station covering a full annual cycle, paired with air origin information, and providing a valuable assessment of tropospheric composition and its potential utility. The first regional model of tropospheric N2O isotopic composition was developed for further assessment of expected variability and utility of isotopic composition data. The optimized fully-automated, liquid-cryogen-free pre-concentration device coupled to continuous flow IRMS resulted in 15N site-specific precisions markedly improved over other systems of 0.11 and 0.14 0/00 (1[sigma]) for [delta]15N[alpha] and [delta]15Nbulk, respectively, and among the best bulk composition precisions of 0.05 and 0.10 0/00 for [delta]15Nbulk and [delta]18O, respectively. The high-precision, non-continuous flask observations of N2O 15N site-specific composition (January 2010 to January 2011; Mace Head Atmospheric Research Station, Ireland) detected statistically significant signals on short-term and annual timescales, and when analyzed with air history information showed consistencies with source-receptor relationships. No seasonal cycle could be detected in the low-frequency observations, but regional model scenarios of the stratospheric seasonal signal resulted in amplitudes at the cusp of current measurement capabilities. This thesis illustrated detectable variations in tropospheric N2O isotopic composition which can potentially reduce uncertainty in the N2O budget with high-frequency, high-precision observations, now feasible by the instrumentation developed here.

Download or read book Isotopic Studies of Nitrate and Nitrogen Dioxide written by Greg Michalski and published by . This book was released on 2003 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Gas Age written by and published by . This book was released on 1919 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiple Stable Oxygen Isotopic Studies of Atmospheric Sulfate written by Charles Chi-Woo Lee and published by . This book was released on 2000 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: