Chemically active climate compounds are either primary compounds like methane (CH4), removed by oxidation in the atmosphere, or secondary compounds like ozone (O3), sulfate and organic aerosols, both formed and removed in the atmosphere. Man-induced climate-chemistry interaction is a two-way process: Emissions of pollutants change the atmospheric composition contributing to climate change through the aforementioned climate components, and climate change, through changes in temperature, dynamics, the hydrological cycle, atmospheric stability, and biosphere-atmosphere interactions, affects the atmospheric composition and oxidation processes in the troposphere. Here we present progress in our understanding of processes of importance for climate-chemistry interactions, and their contributions to changes in atmospheric composition and climate forcing. A key factor is the oxidation potential involving compounds like O3 and the hydroxyl radical (OH). Reported studies represent both current and future ...
NOy (total reactive nitrogen) contained in ice particles was measured on board the NASA DC-8 aircraft in the Arctic in January and March 2000. During some of the flights, the DC-8 encountered widespread cirrus clouds. Large quantities of ice particles were observed at 8 -12 km and particulate NOy showed large increases. The data indicate that the amount of NOy covering the cirrus ice particles strongly depended on temperature. Similar measurements were made in the upper troposphere over the tropical Pacific Ocean in August - September 1998 and 1999. The data obtained in the Arctic and tropics show very limited uptake of NOy on ice at temperatures above 215 K. I NDEX T ERMS : 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0320 Atmospheric Composition and Structure: Cloud physics and chemistry; 0365 Atmospheric Composition and Structure: Troposphere-composition and chemistry.. ...
Satellite measurements from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) are used to examine the global, seasonal variations of several hydrocarbons, including carbon monoxide (CO), ethane (C2H6), acetylene (C2H2), and hydrogen cyanide (HCN). We focus on quantifying large-scale seasonal behavior from the middle troposphere to the stratosphere, particularly in the tropics, and furthermore make detailed comparisons with the Whole Atmosphere Community Climate Model (WACCM) chemistry climate model (incorporating tropospheric photochemistry, time-varying hydrocarbon emissions, and meteorological fields nudged from reanalysis). Comparisons with Microwave Limb Sounder (MLS) measurements of CO are also included to understand sampling limitations of the ACE-FTS data and biases among observational data sets. Results show similar overall variability for CO, C2H6, and C2H2, with a semiannual cycle in the tropical upper troposphere related to seasonallyvarying sources and ...
Upper troposphere cloud top heights (CTHs), restricted to cloud top pressures (CTPs) , 500 hPa, inferred using four satellite retrieval methods applied to Twelfth Geostationary Operational Environmental Satellite (GOES‐12) data are evaluated using measurements during the July-August 2007 Tropical Composition, Cloud and Climate Coupling Experiment (TC4). The four methods are the single‐layer CO2‐absorption technique (SCO2AT), a modified CO2‐absorption technique (MCO2AT) developed for improving both single‐layered and multilayered cloud retrievals, a standard version of the Visible Infrared Solar‐infrared Split‐window Technique (old VISST), and a new version of VISST (new VISST) recently developed to improve cloud property retrievals. They are evaluated by comparing with ER‐2 aircraft‐based Cloud Physics Lidar (CPL) data taken during 9 days having extensive upper troposphere cirrus, anvil, and convective clouds. Compared to the 89% coverage by upper tropospheric clouds detected ...
First, we simply cannot mix the air in the troposphere and the stratosphere. The troposphere is the layer of the atmosphere at the earths surface. The troposphere contains 75% of all the air found in our atmosphere and 99% of the water vapor. The air in the troposphere is in constant motion, with both horizontal and vertical air currents. The combination of vigorous air movement and water vapor creates weather. The troposphere is capped by a thin layer known as the tropopause, which is a region of stable temperature that helps to confine most weather phenomena and bad ozone to the troposphere. The stratosphere is the second layer in the atmosphere from the earths surface. The lower part of the stratosphere contains the ozone layer. The ozone layer prevents harmful ultraviolet radiation from reaching the earths surface by absorbing the rays, causing the ozone layer and the air above it to warm. The warm air tends to remain in the upper stratosphere, and cool air remains lower. The layering ...
Welcome to the Troposphere. The lowest layer of our Earths atmosphere lies just below the Stratosphere and is the place where earthy sounds meet the cosmos. The Limited Edition Tropo Strat features a new set of pickups that deliver those cosmic tones to the most discerning ear. Developed in the Custom Shop by master builder Paul Waller, Tropo Strat pickups are underwound, sweet-sounding pickups that allow more headroom with overdriven sounds and clean up for the most delicate tones to emerge. Its a calibrated pickup set with 50s-style formvar wire on the bridge pickup, a reverse-wound/reverse-polarity middle pickup, and 60s-style enamel wire on the neck pickup.. The Troposphere Strat features a two-piece off-center-seam alder body and single-piece tinted rift-sawn maple neck with a 57 soft V back-shape, 7.25-9.5 fingerboard radius and 21 medium vintage frets. Tropo pickups feature five-way switching and vintage modified #2 wiring with tone-saver treble bleed. Other features include a ...
A new multi-wavelength lidar is introduced. The characteristics of 532 nm extinction coefficient profiles of cloud and aerosol in the upper troposphere in Beijing from January to April, 2000 are emphatically analyzed.Results show that the aerosol optical depth between 6 km and 11 km changes from 0.0152 to 0.0284 with a mean value of 0.0192?The cloud optical depth between 6 km and 11 km ranges from 0.014 to 0.23. The largest cloud thickness is about 6 km. On April 6, a very strong dust storm appeared over Beijing area. On April 7, there was no visible cloud; while as shown in lidar measurements, there was an aerosol layer spread from 4 km to 10 km. This aerosol layer, estimated as the sand-dust layer transported from remote desert areas, has the largest extinction coefficient at the height of about 8 km,which is about one order of magnitude larger than that in the clear (no cloud) day.
In situ measurements of water vapor and temperature from recent aircraft campaigns have provided evidence that the upper troposphere is frequently supersaturated with respect to ice. The peak relative humidities with respect to ice (RHI) occasionally approached water saturation at temperatures ranging from -40°C to -70°C in each of the campaigns. The occurrence frequency of ice supersaturation ranged from about 20% to 45%. Even on flight segments when no ice crystals were detected, ice supersaturation was measured about 5-20% of the time. A numerical cloud model is used to simulate the formation of optically thin, low ice number density cirrus clouds in these supersaturated regions. The potential for scavenging of ice nuclei (IN) by these clouds is evaluated. The simulations suggest that if less than about 5 x 10¯³ to 2 x 10¯² cm¯³ ice nuclei are present when these supersaturations are generated, then the cirrus formed should be subvisible. These low ice number density clouds scavenge ...
Theme: Basic processes. Start date: Cohort 1: 2019. Supervisors: Dr Bryan Bzdek (Bristol) and Dr Matthew Watson (Bristol). The surface tension of atmospheric aerosols impacts their ability to serve as cloud droplet seeds and affect climate. This project will develop approaches to measure droplet surface tensions and better resolve dynamics at the particle surface, working closely with modellers.. Abstract: Atmospheric aerosols affect climate by direct scattering or absorption of solar radiation and indirectly, by serving as Cloud Condensation Nuclei (CCN) and forming cloud droplets. Atmospheric aerosols provide the largest negative radiative forcing, whilst remaining as the contribution with the largest uncertainty. The surface properties of atmospheric aerosol are crucial due to their high surface-to-volume ratios, whilst determining the fraction of atmospheric aerosol that may form cloud droplets. Most climate models still assume that activating CCN have a surface tension equivalent to pure ...
A 2-dimensional atmospheric transport model is deployed in a simplified CO2 inverse study. Calculated carbon flux distribution for the interval from 1981 to 1997 confirms the existence of a terrestrial carbon sink in mid-high latitude area of North Hemisphere. Strong interannual variability exists in carbon flux patterns, implying a possible link with ENSO and other natural episodes such as Pinatubo volcano eruption in 1991. Mechanism of this possible link was investigated with statistic method. Correlation analysis indicated that in North Hemisphere, climatic factors such as temperature and precipitation, to some extend, could influence the carbon cycle process of land and ocean, thus cause considerable change in carbon flux distribution. In addition, correlation study also demonstrated the possible important role of Asian terrestrial ecosystems in carbon cycle.;A 2-dimensional atmospheric transport model is deployed in a simplified CO2 inverse study. Calculated carbon flux
The only single-source reference available on atmospheric chemistry, aerosols, and atmospheric models This fully revised and expanded version of John H. Seinfelds successful Atmospheric Chemistry and Physics of Air Pollution provides a rigorous, comprehensive treatment of the chemistry of the atmosphere. With new chapters on such important topics as cloud physics, nucleation, and wet deposition, this book offers a truly up-to-date examination of atmospheric chemistry today, including: * Chemistry of the stratosphere and troposphere * Formation, growth, dynamics, thermodynamics, and properties of aerosols * Meteorology of air pollution * Transport, diffusion, and removal of species in the atmosphere * Formation and chemistry of clouds * Interaction of atmospheric chemistry and climate * Radiative and climatic effects of gases and particles * Formulation of mathematical chemical/transport models of the atmosphere. Complete with solved examples, problems graded according to difficulty, and hundreds of
CLICK TO ENLARGE (Credit: Image courtesy of DOE/Lawrence Livermore National Laboratory). ScienceDaily (Oct. 10, 2008) - A team led by Livermore scientists has helped reconcile the differences between simulated and observed temperature trends in the tropics.. Using state-of-the-art observational datasets and results from computer model simulations archived at Lawrence Livermore National Laboratory, LLNL researchers and colleagues from 11 other scientific institutions have refuted a recent claim that simulated temperature trends in the tropics are fundamentally inconsistent with observations. This claim was based on the application of a flawed statistical test and the use of older observational datasets.. Climate model experiments invariably predict that human-caused greenhouse gas increases should lead to more warming in the tropical troposphere (the lowest layer of the atmosphere) than at the tropical land and ocean surface. This predicted amplification behavior is in accord with basic ...
We have run a dry, nonlinear, primitive equation spectral model with no externally forced variability and with a realistic time mean state, and we have observed low frequency variability (LFV) in the stratosphere with timescales on the order of hundreds of days. Time lagged correlations have revealed that this variability is linked to LFV in the emission of longwaves from the troposphere. A set of linear model experiments is performed to determine the source of the stratospheric LFV. One set of runs reveal the lowest levels of the model troposphere as the source of most of the relevant forcing. A second set of runs forced with nonlinear terms has shown that the nonlinear interaction among shortwave, high-frequency eddy thermal anomalies in the troposphere has a beating effect which emits vertically propagating low-frequency longwaves. We also see that the eddies act in such a way as to offset the effects of linear temperature advection, allowing the thermal eddies to persist for long periods ...
Lyrics to Troposphere by Steve Burns: Sit right next to me / Against the glass / Where we both can see / Focus on the ground / Disbelief of
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In the framework of the third phase of the Air Quality Model Evaluation International Initiative (AQMEII3), and as contribution to the second phase of the Hemispheric Transport of Air Pollution (HTAP2) activities for Europe and North America, the impacts of a 20% decrease of global and regional anthropogenic emissions on surface air pollutant levels in 2010 are simulated by an international community of regional-scale air quality modeling groups, using different state-of-the-art chemistry and transport models (CTMs). The emission perturbations at the global level, as well as over the HTAP2-defined regions of Europe, North America and East Asia, are first simulated by the global Composition Integrated Forecasting System (C-IFS) model from European Centre for Medium-Range-Weather Forecasts (ECMWF), which provides boundary conditions to the various regional CTMs participating in AQMEII3. On top of the perturbed boundary conditions, the regional CTMs used the same set of perturbed emissions within the
in Geophysical Research Abstracts (2009, April), 11(EGU2009-10017-1), Carbon monoxide (CO) is an important reactive gas in the troposphere. It is emitted at the ground level by fossil fuel combustion and biomass burning. Biogenic sources and oceans as well as oxidation of ... [more ▼]. Carbon monoxide (CO) is an important reactive gas in the troposphere. It is emitted at the ground level by fossil fuel combustion and biomass burning. Biogenic sources and oceans as well as oxidation of methane and nonmethane hydrocarbons complete the emissions budget. Large uncertainties still affect the relative contributions of the identified anthropogenic and natural sources. Destruction by the hydroxyl radical (OH) is the main removal process for CO in both the troposphere and the stratosphere. The resulting average tropospheric lifetime of CO varies from several weeks to a few months. Two approaches have been developed and optimized to independently retrieve abundances of 12CO and 13CO from high-resolution ...
Michelle Santee Group Supervisor Education B.S. Mechanical and Aerospace Engineering, Cornell University (1982) M.S. Aerospace Engineering, University of Texas at Austin (1984) M.S. Planetary Science, California Institute of Technology (1989) Ph.D. Planetary Science, California Institute of Technology (1993) Research Interests Processes controlling trace
View Notes - Topic_22___Human_Effects_Atmos from GEO 302C at University of Texas. Study Questions Topic 22: Human Impacts on the Atmosphere Lecture Outline I. Atmospheric change and sensitivity II.
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The Arctic is affected by climate change much stronger than other regions of the globe. Permafrost thawing can lead to additional methane release, which enhances the greenhouse effect and warming, as well as changes of Arctic tundra ecosystems. A great part of Siberian Arctic is still unexplored. Ground-based investigations are difficult to be carried out in this area due to it is an out-of-the-way place. So, in spite of the high cost, aircraft-based in-situ measurements can provide a good opportunity to fill up the gap in data on the atmospheric composition over this region.
Abstract. Over the past few decades, the geographical distribution of emissions of substances that alter the atmospheric energy balance has changed due to economic growth and air pollution regulations. Here, we show the resulting changes to aerosol and ozone abundances and their radiative forcing using recently updated emission data for the period 1990-2015, as simulated by seven global atmospheric composition models. The models broadly reproduce large-scale changes in surface aerosol and ozone based on observations (e.g. −1 to −3 % yr−1 in aerosols over the USA and Europe). The global mean radiative forcing due to ozone and aerosol changes over the 1990-2015 period increased by +0.17 ± 0.08 W m−2, with approximately one-third due to ozone. This increase is more strongly positive than that reported in IPCC AR5. The main reasons for the increased positive radiative forcing of aerosols over this period are the substantial reduction of global mean SO2 emissions, which is stronger in the ...
My research is about physical and chemical air-snow exchange processes to gain a better understanding of how snow and ice surfaces influence atmospheric composition and oxidation capacity, and ultimately climate, with a focus on tropospheric ozone, the nitrogen and sulfur cycle, halogen chemistry, as well as aerosol formation and growth. Further aims are to quantify the preservation of chemical trace species in snow and ice to develop proxies of atmospheric composition in the past using ice cores.. In the field and lab I use a range of detectors to measure chemical species in air, snow and ice at the ultra-trace level, as well as spectrometers to determine particle size and concentration. I also use and develop box and 1-D models to interpret experimental data. To date Ive lead and managed 15 atmospheric sampling and ice coring projects on expeditions to Antarctica, the Arctic and the Bolivian Andes, including three polar sea ice cruises during winter.. Graduate Students & Post-Doctoral ...
Abstract. Carbon cycling in the Amazon is closely linked to atmospheric processes and climate in the region as a consequence of the strong coupling between the atmosphere and biosphere. This work examines the effects of changes in net radiation due to atmospheric aerosol particles and clouds on the net ecosystem exchange (NEE) of CO2 in the Amazon region. Some of the major environmental factors affecting the photosynthetic activity of plants, such as air temperature and relative humidity, were also examined. An algorithm for clear-sky irradiance was developed and used to determine the relative irradiance, f, which quantifies the percentage of solar radiation absorbed and scattered due to atmospheric aerosol particles and clouds. Aerosol optical depth (AOD) was calculated from irradiances measured with the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor, onboard the Terra and Aqua satellites, and was validated with ground-based AOD measurements from AERONET (Aerosol Robotic Network) ...
Nitrogen (N) compounds in the lowest two layers of the atmosphere are important in current environmental issues. The lowest layer, the troposphere, extends from the earth s surface up to about 10 kilometers. The next layer, the stratosphere, extends from about 10 to about 50 kilometers above the ground. Mixing between the two layers is quite slow. Radionuclides that were injected into the stratosphere during atmospheric testing of nuclear weapons had a lifetime on the order of months to a few years in the stratosphere before episodic mixing events would eventually bring the bomb debris into the troposphere where it would have a lifetime of days to weeks before being deposited onto the earth s surface (Junge, 1963). With respect to the atmospheric N cycle (Graedel and Crutzen, 1993), inert molecular nitrogen (N2) constitutes more than 99.9999% of the N present in the atmosphere. Nitrous oxide (N2O), making up more than 99% of the remainder of the N in the atmosphere, is an important greenhouse ...
Nitrogen (N) compounds in the lowest two layers of the atmosphere are important in current environmental issues. The lowest layer, the troposphere, extends from the earth s surface up to about 10 kilometers. The next layer, the stratosphere, extends from about 10 to about 50 kilometers above the ground. Mixing between the two layers is quite slow. Radionuclides that were injected into the stratosphere during atmospheric testing of nuclear weapons had a lifetime on the order of months to a few years in the stratosphere before episodic mixing events would eventually bring the bomb debris into the troposphere where it would have a lifetime of days to weeks before being deposited onto the earth s surface (Junge, 1963). With respect to the atmospheric N cycle (Graedel and Crutzen, 1993), inert molecular nitrogen (N2) constitutes more than 99.9999% of the N present in the atmosphere. Nitrous oxide (N2O), making up more than 99% of the remainder of the N in the atmosphere, is an important greenhouse ...
a) Each of these Parties shall adopt national policies and take corresponding measures on the mitigation of climate change, by limiting its anthropogenic emissions of greenhouse gases and protecting and enhancing its greenhouse gas sinks and reservoirs. These policies and measures will demonstrate that developed countries are taking the lead in modifying longer-term trends in anthropogenic emissions consistent with the objective of the Convention, recognizing that the return by the end of the present decade to earlier levels of anthropogenic emissions of carbon dioxide and other greenhouse gases not controlled by the Montreal Protocol would contribute to such modification, and taking into account the differences in these Parties starting points and approaches, economic structures and resource bases, the need to maintain strong and sustainable economic growth, available technologies and other individual circumstances, as well as the need for equitable and appropriate contributions by each of ...
Satellites that orbit Earth help us study Earths atmosphere, weather, and climate. Here are a few of the many spacecraft that study our atmosphere.. Aura was launched in July 2004. It is studying pollution, gases that may be related to climate change, and ozone. IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) has been in space studying Earths plasmasphere since March 2000. Polar, which was launched in 1996, observes aurora and the polar magnetosphere. UARS (Upper Atmosphere Research Satellite) was launched from the space shuttle in 1991. UARS studies many aspects of the atmosphere, especially chemistry in the middle and upper stratosphere. UARS is old, and only half of its instruments are still working; but it has gathered lots of valuable data over the years.. More satellites will be launched in the future to study the atmosphere. COSMIC (Constellation Observing System for Meteorology, Ionosphere & Climate) is a group of satellites that will be launched in the spring of 2005. ...
Figure 2: The vertical structure of changes in atmospheric temperature in satellite observations (top panel) and in computer model simulations performed as part of phase 5 of the Coupled Model Intercomparison Project (CMIP-5; bottom panel). As described in the PNAS paper, both panels provide a vertically smoothed picture of atmospheric temperature change. Information from only three atmospheric temperature layers - the lower stratosphere (TLS), the mid- to upper troposphere (TMT), and the lower troposphere (TLT) was used in generating the two plots. We show temperature changes in this vertically smoothed space because satellite-based estimates of atmospheric temperature change are available for TLS, TMT, and TLT, and because our signal detection study is performed with the zonally-averaged temperature changes for these three layers. All temperature changes are in the form of linear trends (in degrees Celsius) over the 408-month period from ...
Excess carbon dioxide, methane, and other gases which trap heat are accumulating in the troposphere, the earths lower atmosphere, because of the scale and type of human economic activity. Climate scientists predict that the resultant increase in the tropospheres radiative forcing will warm the earths surface.1 2 3 Indeed, in its recent second assessment report, the Intergovernmental Panel on Climate Change-a multidisciplinary scientific body established by the United Nations in 1988 to advise governments-concluded that on balance an anthropogenic influence upon the global climate was now discernible. 1. The intergovernmental panel forecasts an increase in the average world temperature of 1.0-3.5°C over the coming century.1 This forecast is necessarily uncertain because the sensitivity of climate to atmospheric change is imperfectly understood and because future trends in gaseous emissions and modulating processes (for example, the cooling effects of industrial aerosol emissions) cannot ...
A theory for the ocean-atmosphere partitioning of anthropogenic carbon dioxide on centennial timescales is presented. The partial pressure of atmospheric CO2 (PCO2) is related to the external CO2 input (Δ∑C) at air-sea equilibrium by: PCO2 = 280 ppm exp(Δ∑C/[IA + IO/R]), where IA, IO, and R are the pre-industrial values of the atmospheric CO2 inventory, the oceanic dissolved inorganic carbon inventory, and the Revelle buffer factor of seawater, respectively. This analytical expression is tested with two- and three-box ocean models, as well as for a version of the Massachusetts Institute of Technology general circulation model (MIT GCM) with a constant circulation field, and found to be valid by at least 10% accuracy for emissions lower than 4500 GtC. This relationship provides the stable level that PCO2 reaches for a given emission size, until atmospheric carbon is reduced on weathering timescales. On the basis of the MIT GCM, future carbon emissions must be restricted to a total of 700 ...
Atmospheric aerosols play an important role in climate by scattering and absorbing radiation and by serving as cloud condensation nuclei. An aerosols optical or nucleation properties are driven by its chemical composition. Chemical aging of aerosols by atmospheric oxidants, such as ozone, alters the physiochemical properties of aerosol to become more hygroscopic, light absorbing, and viscous during transport. However the mechanism of these transformations is poorly understood. While ozone is a protective and beneficial atmospheric gas in the stratosphere, it is a potent greenhouse gas in the troposphere that traps heat near the Earths surface. It also impacts human heath by irritating the respiratory tract and exacerbating cardiovascular diseases. Additionally, ozone can alter the ecosystem through oxidizing plant foliage which can lead to deforestation and crop losses as well. Both gases and aerosols in the troposphere can react with ozone directly and indirectly with hydroxyl radicals. While daytime
Tropospheric propagation describes electromagnetic propagation in relation to the troposphere. The service area from a VHF or UHF radio transmitter extends to just beyond the optical horizon, at which point signals start to rapidly reduce in strength. Viewers living in such a deep fringe reception area will notice that during certain conditions, weak signals normally masked by noise increase in signal strength to allow quality reception. Such conditions are related to the current state of the troposphere. Tropospheric propagated signals travel in the part of the atmosphere adjacent to the surface and extending to some 25,000 feet (7,620 m). Such signals are thus directly affected by weather conditions extending over some hundreds of miles. During very settled, warm anticyclonic weather (i.e., high pressure), usually weak signals from distant transmitters improve in strength. Another symptom during such conditions may be interference to the local transmitter resulting in co-channel ...
Aitken, J.: XVI - The Sun as a Fog Producer, P. R. Soc. Edin., 32, 183-215, https://doi.org/10.1017/s0370164600012864, 1912. Cai, R. and Jiang, J.: A new balance formula to estimate new particle formation rate: reevaluating the effect of coagulation scavenging, Atmos. Chem. Phys., 17, 12659-12675, https://doi.org/10.5194/acp-17-12659-2017, 2017. Cai, R., Chen, D.-R., Hao, J., and Jiang, J.: A miniature cylindrical differential mobility analyzer for sub-3 nm particle sizing, J. Aerosol Sci., 106, 111-119, https://doi.org/10.1016/j.jaerosci.2017.01.004, 2017a. Cai, R., Yang, D., Fu, Y., Wang, X., Li, X., Ma, Y., Hao, J., Zheng, J., and Jiang, J.: Aerosol surface area concentration: a governing factor in new particle formation in Beijing, Atmos. Chem. Phys., 17, 12327-12340, https://doi.org/10.5194/acp-17-12327-2017, 2017b. Chandra, I., Kim, S., Seto, T., Otani, Y., Takami, A., Yoshino, A., Irei, S., Park, K., Takamura, T., Kaneyasu, N., and Hatakeyama, S.: New particle formation under the ...
TY - JOUR. T1 - Onset of the aerobic nitrogen cycle during the Great Oxidation Event. AU - Zerkle,Aubrey L.. AU - Poulton,Simon W.. AU - Newton,Robert J.. AU - Mettam,Colin. AU - Claire,Mark W.. AU - Bekker,Andrey. AU - Junium,Christopher K.. PY - 2017/2/23. Y1 - 2017/2/23. N2 - The rise of oxygen on the early Earth (about 2.4 billion years ago) caused a reorganization of marine nutrient cycles, including that of nitrogen, which is important for controlling global primary productivity. However, current geochemical records lack the temporal resolution to address the nature and timing of the biogeochemical response to oxygenation directly. Here we couple records of ocean redox chemistry with nitrogen isotope (15N/14N) values from approximately 2.31-billion-year-old shales of the Rooihoogte and Timeball Hill formations in South Africa, deposited during the early stages of the first rise in atmospheric oxygen on the Earth (the Great Oxidation Event). Our data fill a gap of about 400 million years in ...
R/9392/297 NATO advanced study institute series. Ser.C., Mathematical and physical sciences [Text]. - Dordrecht etc. : Kluwer.Vol. 297 : long-range atmospheric transport of natural and contaminant substances : proc. of the NATO advanced research workshop on the long-range atmospheric transport of natural and contaminant substances St.Georges,Bermuda Jan.10-17,1989 / Ed.: A.H.Knap; Ed.: M.S.Kaiser ; NATO advanced research workshop on the long-range atmospheric transport of natural and contaminant substances (1989; St.Georges). - Dordrecht etc. : kluwer acad. publ., 1990. - XXI,321 p. : ill. - ISBN 0-7923-0577-9 : 161.78 р.ГРНТИ 2729УДК 51(082.1)53(082.1) Держатели документа: ГПНТБ России Доп.точки доступа: Knap, A.H. \ed.\; Kaiser, M.S. \ed.\; NATO advanced research workshop on the long-range atmospheric transport of natural and contaminant substances (1989 ; St.Georges) Экз-ры: ХР(1) Копия: мкф., Шифр MR-99611 SUBSTANCES$ ...
Researchers are invited to present novel scientific results from mid- and long-term observational time series from various measurements networks such as Global Atmosphere Watch (GAW), European Monitoring and Evaluation Programme (EMEP), Network for the Detection of Atmospheric Composition Change (NDACC), Southern Hemisphere Additional Ozonesondes (SHADOZ), Advanced Global Atmospheric Gases Experiment (AGAGE), National Oceanic and Atmospheric Administration (NOAA), regular airborne (e.g. MOZAIC, CARIBIC) and other campaigns as well as satellite data and model simulations. Data relevant to tropospheric and stratospheric composition, in particular related to ozone depletion, climate change and air quality as well as firn data on past atmospheric composition are welcome. We welcome contributions from multi-year modeling studies and inter-comparison exercises which address tropospheric or stratospheric composition changes, carried out in the framework of international projects (e.g. GEOMON, MACC) and ...
AWIs MARL-instrument is a mobile backscatter lidar that is used at various locations as well as aboard the research vessel Polarstern to measure Aerosol and clouds in the upper troposphere and lower stratosphere. In 2000 two field-experiments have been conducted within the European INCA 2000-project (Interhemispheric differences in cirrus cloud properties by anthropogenic emissions). The first one took place in the southern hemispheric midlatitudes, in Punta Arenas/Chile (53.12°S, 70.88°W) and the second campaign followed in September 2000 in Prestwick /Scotland (55.51°N, 4.60°W). The main objective of these activities was to collect Lidar data on cirrus clouds from clean (Punta Arenas) and polluted (Prestwick) areas. During the four weeks of the campaigns, around 80 h of Lidar measure-ments were gathered at each location, covering different types of cirrus clouds as well as background aerosols. A comparison of the two datasets reveals similarities as well as differ-ences in the measured ...
The fifth most abundant gas in the atmosphere is carbon dioxide. The volume of this gas has increased by over 35% in the last three hundred years (see Figure 7a-1). This increase is primarily due to human induced burning from fossil fuels, deforestation, and other forms of land-use change. Carbon dioxide is an important greenhouse gas. The human-caused increase in its concentration in the atmosphere has strengthened the greenhouse effect and has definitely contributed to global warming over the last 100 years. Carbon dioxide is also naturally exchanged between the atmosphere and life through the processes of photosynthesis and respiration.. Methane is a very strong greenhouse gas. Since 1750, methane concentrations in the atmosphere have increased by more than 150%. The primary sources for the additional methane added to the atmosphere (in order of importance) are: rice cultivation; domestic grazing animals; termites; landfills; coal mining; and, oil and gas extraction. Anaerobic conditions ...
We describe and show results from a series of field campaigns using balloon-borne instruments launched from India and Saudi Arabia during the summers 2014-2017 to study the nature, formation and impacts of the Asian Tropopause Aerosol Layer (ATAL). The campaign goals were to i) characterize the optical, physical and chemical properties of the ATAL, ii) assess its impacts on water vapor and ozone, and iii) understand the role of convection in its formation. In order to address these objectives, we launched 68 balloons from 4 locations, one in Saudi-Arabia and 3 in India, with payload weights ranging from 1.5 kg to 50 kg. We measured meteorological parameters, ozone, water vapor, and aerosol backscatter, concentration, volatility and composition in the Upper Troposphere and Lower Stratosphere (UTLS) region. We found peaks in aerosol concentrations of up to 25 part/cm3 for radius | 75 nm, associated with Scattering Ratio at 940 nm of ~1.9 near the cold point tropopause. During medium-duration balloon
The stratosphere … in contrast to the troposphere, is heated, as the result of near infrared absorption of solar energy at the top of the aerosol cloud, and increased infra-red absorption of long-wave radiation from the Earths surface.. The stratospheric warming in the region of the stratospheric cloud increases the latitudinal temperature gradient after an eruption at low latitudes, disturbing the stratospheric-troposphere circulation, increasing the difference in height of the troposphere between high and low latitudes, and increasing the strength of the jet stream (polar vortex, especially in the northern hemisphere). This leads to warming during the northern hemisphere winter following a tropical eruption, and this warming effect tends to be larger than the cooling effect described above. Ellen Thomas, PHD Wesleyan University. The Lower Stratosphere experienced dramatic warming events caused by the eruptions of El Chichon (1982) and Mt Pinatubo (1991). RSS The long-term, ...
In meteorology, a cloud is an aerosol comprising a visible mass of minute liquid droplets, frozen crystals, or particles suspended in the atmosphere above the surface of a planetary body. The droplets and crystals may be made of water or various chemicals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture (usually in the form of water vapor) from an adjacent source to raise the dew point to the ambient temperature. They are seen in the Earths homosphere (which includes the troposphere, stratosphere, and mesosphere). Nephology is the science of clouds which is undertaken in the cloud physics branch of meteorology. There are two methods of naming clouds in their respective layers of the atmosphere; Latin and common. Cloud types in the troposphere, the atmospheric layer closest to Earths surface, have Latin names due to the universal adaptation of Luke Howards nomenclature. Formally proposed in 1802, it ...
Hygroscopic property of atmospheric aerosols is essential to understand effect of aerosols on cloud formation by acting as cloud condensation nuclei (CCN), which leads to climate change with cloud albedo effect. Also, hygroscopic property of particles is important to determine their transport behaviors and fates in the ambient atmosphere and to understnd their deposition pattern in the human respiratory system when they were inhaled. This book describes a hygroscopicity tandem differential mobility analyzer (HTDMA) system in details to measure hygroscopic property of atmospheric aerosols in real time by measuring particle size change at an increased relative humidity. (Imprint: Novinka). ...
Increased UV-B through stratospheric ozone depletion leads to an increased chemical activity in the lower atmosphere (the troposphere). The effect of stratospheric ozone depletion on tropospheric ozone is small (though significant) compared to the ozone generated anthropogenically in areas already experiencing air pollution. Modeling and experimental studies suggest that the impacts of stratospheric ozone depletion on tropospheric ozone are different at different altitudes and for different chemical regimes. As a result the increase in ozone due to stratospheric ozone depletion may be greater in polluted regions. Attributable effects on concentrations are expected only in regions where local emissions make minor contributions. The vertical distribution of NOx (NO + NO2), the emission of volatile organic compounds and the abundance of water vapor, are important influencing factors. The long-term nature of stratospheric ozone depletion means that even a small increase in tropospheric ozone ...
A comprehensive group of reactive nitrogen species (NO, NO2, HNO3, HO2NO2, PANs, alkyl nitrates, and aerosol-NOÀ) were measured over North America during 3 July/August 2004 from the NASA DC-8 platform (0.1-12 km). Nitrogen containing tracers of biomass combustion (HCN and CH3CN) were also measured along with a host of other gaseous (CO, VOC, OVOC, halocarbon) and aerosol tracers. Clean background air as well as air with influences from biogenic emissions, anthropogenic pollution, biomass combustion, convection, lightning, and the stratosphere was sampled over the continental United States, the Atlantic, and the Pacific. The North American upper troposphere (UT) was found to be greatly influenced by both lightning NOx and surface pollution lofted via convection and contained elevated concentrations of PAN, ozone, hydrocarbons, and NOx. Observational data suggest that lightning was a far greater contributor to NOx in the UT than previously believed. PAN provided a dominant reservoir of reactive ...
TY - JOUR. T1 - Evidence of aqueous secondary organic aerosol formation from biogenic emissions in the North American Sonoran Desert. AU - Youn, Jong Sang. AU - Wang, Zhen. AU - Wonaschütz, Anna. AU - Arellano, Avelino F. AU - Betterton, Eric. AU - Sorooshian, Armin. PY - 2013/7/16. Y1 - 2013/7/16. N2 - This study examines the role of aqueous secondary organic aerosol formation in the North American Sonoran Desert as a result of intense solar radiation, enhanced moisture, and biogenic volatile organic compounds (BVOCs). The ratio of water-soluble organic carbon (WSOC) to organic carbon (OC) nearly doubles during the monsoon season relative to other seasons of the year. When normalized by mixing height, the WSOC enhancement during monsoon months relative to preceding dry months (May-June) exceeds that of sulfate by nearly a factor of 10. WSOC:OC and WSOC are most strongly correlated with moisture parameters, temperature, and concentrations of O3 and BVOCs. No positive relationship was identified ...
F Raes, R van Dingenen, E Cuevas, PFJ van Velthoven, JM Prospero. Observations of aerosols in the free troposphere and marine boundary layer of the subtropical Northeast Atlantic: discussion of the processes determining their size distrubution ...
Introduction. Nour Jafar Mrs. Elsen Chemistry 10 February 24, 2010 Stratospheric Ozone and CFCs In Earths atmosphere, there are different layers. The troposphere is the innermost level. It is the first layer from Earths atmosphere. Following the troposphere is the stratosphere, then the mesosphere, thermosphere, and finally the exosphere (Importance of the Ozone Layer par. 3). In the stratosphere, there is a thin layer of gas called ozone. Ozone is a gas naturally present in the environment. It is similar to the gas oxygen, but ozone is a light blue tint (Morgan 4). Diagram Source: Draget.net Currently, the world is facing a global crisis. This crisis is the ozone layer is thinning, especially over Antarctica, causing an ozone hole (Morgan 4). In the early 1970s, scientists found that substances used in aerosol, or spray, cans damaged ozone molecules. The substances used in the spray cans were used as a propellant, making the spray cans mechanism work (Morgan 12). Because of their ...
The US federal government has taken numerous actions to require cost / benefit analyses, or cost effectiveness analyses, regarding federal rulemaking activities. The intent of these actions is to assure that the rulemaking activities provide real benefits at acceptable costs. However, this intent is violated when the regulatory agencies analyze only the costs, or only the benefits, of proposed actions.. One example of this violation of intent is the federal effort to establish the Social Cost of Carbon, specifically the supposed costs of increased atmospheric carbon dioxide concentrations on society. This effort has totally ignored the social benefits of increased atmospheric carbon dioxide concentrations, despite the well documented effects of enhanced carbon dioxide concentrations on the rate and extent of growth of the field crops used to produce food for people and animals. This effort has also ignored the greening of the globe, largely resulting from increased atmospheric carbon dioxide ...
Multivariate data analysis methods were applied to study the geographical and temporal distribution of tropospheric ozone in Catalonia (North-East Spain). Ozone data were collected during the period 2000-2004 in 41 sampling stations. Data analysis by multivariate curve resolution alternating least squares (MCR-ALS) allowed the recognition of three sub-regions within Catalonia according to their ozone variation patterns. Representation of loadings by means of geographical information systems (GIS) allowed a better visualisation of these areas. Daily, weekly and annual ozone profiles were determined for each sub-region. Principal component analysis (PCA) was applied within each sub-region to unravel the relationship between ozone variation and some other parameters, such as atmospheric pollutants (SO2, H2S, NO, NO2, CO and particulate matter), as well as meteorological variables (temperature, relative humidity, solar radiation, pressure, precipitation and wind speed ...
Abstract. Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric ozone depleting substances (ODS) on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O) emissions. We also find that without the regulation of chlorofluorocarbons (CFCs) through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. ...
Ozone is a gas that is present naturally in the atmosphere. Chemical formula of the ozone is O3 because three oxygen atoms are present in an ozone molecule .On the basis of presence of Ozone, the atmosphere is divided into two regions, troposphere and stratosphere. The troposphere is the closest region from the earth (10- 16 kilometers from the earth surface) and about 10% of the atmospheric ozone is present in this zone. Similarly the stratosphere is 50 kilometers altitude and about 90 % of the ozone is present in this region. Ozone was firstly produced in the laboratory by the European researcher C. F. Schonbein in 1839. Ozone was firstly used commercially in 1907 in municipal water supply treatment in Nice and in 1910 in St. Petersburg the general ozone generation. In order to produce ozone molecule, firstly we split the diatomic oxygen. The resulting free radical oxygen reacts with diatomic oxygen to form the tri-atomic ozone molecule. Nevertheless, in order to break the bond between two ...
Life in Earths oceans may have had a slow start because phosphorus - a key nutrient of life - was not recycled through the biosphere fast enough. The finding, by scientists at the University of Washington and the University of St Andrews, UK, could explain why it took so long for Earths atmosphere to become oxygenated.. By modeling Earths oceans over billions of years, Washingtons Michael Kipp and Eva Stüeken of St Andrews, found that during the Archean (the geological era of between four and 2.5 billion years ago) phosphorus was recycled ten times slower than in the oceans today, resulting in biological productivity slowing down.. This has implications for the presence of oxygen in Earths atmosphere. During the Archean, the atmosphere was dominated by carbon dioxide. Around two-and-a-half billion years ago, oxygen suddenly filled the atmosphere during what is known as the Great Oxygenation Event. It is believed that photosynthesizing life contributed to this oxygen influx, but the first ...
Life in Earths oceans may have had a slow start because phosphorus - a key nutrient of life - was not recycled through the biosphere fast enough. The finding, by scientists at the University of Washington and the University of St Andrews, UK, could explain why it took so long for Earths atmosphere to become oxygenated.. By modeling Earths oceans over billions of years, Washingtons Michael Kipp and Eva Stüeken of St Andrews, found that during the Archean (the geological era of between four and 2.5 billion years ago) phosphorus was recycled ten times slower than in the oceans today, resulting in biological productivity slowing down.. This has implications for the presence of oxygen in Earths atmosphere. During the Archean, the atmosphere was dominated by carbon dioxide. Around two-and-a-half billion years ago, oxygen suddenly filled the atmosphere during what is known as the Great Oxygenation Event. It is believed that photosynthesizing life contributed to this oxygen influx, but the first ...
Life in Earths oceans may have had a slow start because phosphorus - a key nutrient of life - was not recycled through the biosphere fast enough. The finding, by scientists at the University of Washington and the University of St Andrews, UK, could explain why it took so long for Earths atmosphere to become oxygenated.. By modeling Earths oceans over billions of years, Washingtons Michael Kipp and Eva Stüeken of St Andrews, found that during the Archean (the geological era of between four and 2.5 billion years ago) phosphorus was recycled ten times slower than in the oceans today, resulting in biological productivity slowing down.. This has implications for the presence of oxygen in Earths atmosphere. During the Archean, the atmosphere was dominated by carbon dioxide. Around two-and-a-half billion years ago, oxygen suddenly filled the atmosphere during what is known as the Great Oxygenation Event. It is believed that photosynthesizing life contributed to this oxygen influx, but the first ...
Ozone is a form of oxygen having the molecular form of O3. It is a bluish, unstable gas with a pungent odour, found in two parts of the atmosphere: the stratosphere and the troposphere.. The ozone layer: The stratosphere contains a layer in which the concentration of ozone is greatest, the so called ozone layer. The layer extends from about 12 to 40 km. It shields the Earth from ultraviolet radiations harmful health effects on humans and the environment. This layer is being depleted by human emissions of chlorine- and bromine-containing compounds.. Ground-level ozone: At ground level (in the troposphere), ozone is considered an air pollutant that can seriously affect the human respiratory system. It is a chemical oxidant and a major component of photochemical smog.. Source: GreenFacts. ...
Products and mechanism of secondary organic aerosol formation from reactions of linear alkenes with NO3 radicals Journal Article ...
Caption: Schematic overview of the primary black-carbon emission sources and the processes that control the distribution of black carbon in the atmosphere and determine its role in the climate system. (Bond et al. 2013). Their findings was that the total direct forcing of BC, independent of co-emitted aerosol species and including all sources (direct emissions, pre-industrial background, cryosphere and clouds) is +1.1 Wm-2 with an uncertainty range of +0.08 Wm-2 to +2.1 Wm-2. This places BC itself as the 2nd most important anthropogenic emission, behind $\ce{CO2}$. However, when the total radiative effects of BC with co-emitted aerosols, including organic carbon sources are taken into consideration, there is a slight cooling effect, with the total direct radiative forcing of -0.06 Wm-2, with a greater uncertainty range of -1.45 Wm-2 to +1.29 Wm-2.. ...
Atmospheric chemistry research at the University of Maryland is focused on quantification of the effect of human activity on atmospheric ozone and aerosols. Interestingly, pollution leads to higher levels of tropospheric ozone (so-called bad ozone, because ozone in the lower atmosphere is harmful to human health and agriculture) and, at the same time, pollution also leads to reduced levels of stratospheric ozone (so-called good ozone, because ozone in the upper atmosphere protects life from harmful solar ultra-violet radiation). Aerosols, particularly small size particles produced by combustion, pose a significant health risk, especially for children and the elderly. Atmospheric aerosols are also important for the radiative forcing of climate: aerosols caused by pollution can either warm or cool the surface, depending on the composition and optical properties of the particles ...
Let this demonstration slide set guide you as you teach the activity, Modeling Earths Atmosphere, where students create a model of Earths atmosphere.
Let this demonstration slide set guide you as you teach the activity, Modeling Earths Atmosphere, where students create a model of Earths atmosphere.
To assess the relationship between nitrogen concentrations in mosses and wet bulk nitrogen deposition or concentrations in precipitation, moss tissue and deposition were sampled within a distance of 1 km of each other in seven European countries. Relationships for various forms of nitrogen appeared to be asymptotic, with data for different countries being positioned at different locations along the asymptotic relationship and saturation occurring at a wet bulk nitrogen deposition of ca. 20 kg N ha(-1) yr(-1). The asymptotic behaviour was more pronounced for ammonium-N than nitrate-N, with high ammonium deposition at German sites being most influential in providing evidence of the asymptotic behaviour. Within countries, relationships were only significant for Finland and Switzerland and were more or less linear. The results confirm previous relationships described for modelled total deposition. Nitrogen concentration in mosses can be applied to identify areas at risk of high nitrogen deposition ...
Secondary organic aerosol (SOA) derived from isoprene epoxydiols (IEPOX) has potential impacts on regional air quality and climate yet is poorly characterized under NOx-rich ambient environments. We report the first real-time characterization of IEPOX-derived SOA (IEPOX-SOA) in Eastern China in summer 2013 using comprehensive ambient measurements, along with model analysis. The ratio of IEPOX-SOA to isoprene high-NOx SOA precursors, e.g., methyl vinyl ketone and methacrolein, and the reactive uptake potential of IEPOX was lower than those generally observed in regions with prevailing biogenic emissions, low NOx levels, and high particle acidity, elucidating the suppression of IEPOX-SOA formation under NOx-rich environments. IEPOX-SOA showed high potential source regions to the south with large biogenic emissions, illustrating that the interactions between biogenic and anthropogenic emissions might have played an important role in affecting the formation of IEPOX-SOA in polluted environments in ...
After 8 hours exposure in the stratosphere (31 km above sea level), 99.9% of the entire population was destroyed.[9] According to the researchers, most terrestrial bacteria would be inactivated within the first [day] on Mars if contaminated spacecraft surfaces receive direct sunlight.[9] Of the 40 million spores exposed to the stratosphere, only 267 spores (or 0.0007%) remained viable.[2] Extrapolating this, no viable spores would remain if flight samples had an additional 150 minutes of Sun exposure in the stratosphere (630 min total time).[2] The survivors showed three single nucleotide (base pair) substitutions compared to unexposed controls kept on the ground. These three coding regions are associated with bacterial sporulation and metabolism. A similar observation was recorded on SAFR-032 samples that were exposed outside the International Space Station.[9][2] Even after cleaning, spacecraft leaving Earth still carry microorganisms on board that are embedded within surfaces, instruments, ...
The impact of including a more detailed VOC oxidation scheme (CRI v2-R5) with a multi-generational approach for simulating tropospheric acetone is investigated using a 3-D global model, STOCHEM-CRI. The CRI v2-R5 mechanism contains photochemical production of acetone from monoterpenes which account for 64% (46.8 Tg/yr) of the global acetone sources in STOCHEM-CRI. Both photolysis and oxidation by OH in the troposphere contributes equally (42%, each) and dry deposition contributes 16% of the atmospheric sinks of acetone. The tropospheric life-time and the global burden of acetone are found to be 18 days and 3.5 Tg, respectively, these values being close to those reported in the study of Jacob et al. (2002). A dataset of aircraft campaign measurements are used to evaluate the inclusion of acetone formation from monoterpenes in the CRI v2-R5 mechanism used in STOCHEM-CRI. The overall comparison between measurements and models show that the parameterised approach in STOCHEM-NAM (no acetone formation ...
Figure 9 - Average of Global Land+Sea Surface Temperature Anomaly Products. The flatness of the data since 2001 is very obvious, as is the fact that surface temperatures have rarely risen above those created by the 1997/98 El Niño in the surface temperature data. There is a very simple reason for this: the 1997/98 El Niño released enough sunlight-created warm water from beneath the surface of the tropical Pacific to raise the temperature of about 66% of the surface of the global oceans by almost 0.2 deg C. Sea surface temperatures for that portion of the global oceans remained relatively flat, dropping slowly throughout most of that region, until the El Niño of 2009/10, when the surface temperatures of that portion of the global oceans shifted slightly higher again. Prior to that, it was the 1986/87/88 El Niño that caused surface temperatures to shift upwards. If these naturally occurring upward shifts in surface temperatures are new to you, please see the illustrated essay The Manmade ...
Uk based progressive/alt.rock combo Atlas : Empire are glad to announce that they have signed a deal with WormHoleDeath for the reissue of their album The Stratosphere Beneath Our Feet. Steven Gillies (vocals & guitar): We are very excited to be working with WormHoleDeath and are looking forward to Carlo and his team developing and building on everything weve acheived as an independent band. In the current musical climate, its amazing to know we have a label who believes in the art we create - starting with the re-release of The Stratosphere Beneath Our Feet, then supporting us through the entire process for our second album. The Stratosphere Beneath Our Feet will be out on 25 October 2019 via Wormholedeath / The Orchard / Wormholedeath USA. As Yet Unwritten Diminishing Returns Its All In The Reflexes The Moment We Were Exploding Gethsemane The Entire History Of You Hostess The Year Of The Four Emperors Our Hands Part The Waves Cenotaphs Atlas : Empire have also released a video for ...
Climate change is a wicked problem because it is hard to say what the problem is, and to define it clearly. However, we know that global temperature rise correlates with increasing levels of atmospheric carbon dioxide [1] and [2]. In this paper, we analyze a model for the carbon dioxide developed by Walker in [3] with several source terms. Our numerical results show that the burning fossil fuels have an effect on the carbon dioxide in the earths atmosphere and the climate change problem, one of the major global challenger of our time.
Extensive ozone loss occurs each winter over Antarctica (the ozone hole) due to the extreme cold there and its strong, long-lived polar vortex (a band of winds that forms each winter at high latitudes). This vortex isolates the region from middle latitudes. In contrast, the Arctic winter is warmer and its vortex is weaker and shorter-lived. As a result, Arctic ozone loss has always been lower, more variable and much more difficult to quantify.. This was the first Arctic winter monitored by Aura, which was launched in July 2004. Auras Microwave Limb Sounder is contributing to our understanding of the processes that cause Arctic wind patterns to push ozone-rich air to the Arctic lower stratosphere from higher altitudes and lower latitudes. Through Auras findings, scientists can differentiate chemical ozone destruction from ozone level changes caused by air motions, which vary dramatically from year to year. Understanding Arctic ozone loss is critical to diagnosing the health of Earths ozone ...
The chlorofluorocarbons CFC-11 (CFCl3) and CFC-12 (CF2Cl2) are stable atmospheric compounds that are produced at the earths surface, but removed only at high altitudes in the stratosphere by photolytic reactions. Their removal liberates atomic chlorine that then catalytically destroys stratospheric ozone. For such long-lived compounds, isotope effects in the stratospheric removal reactions have a large effect on their global isotope budgets. We have demonstrated a photolytic isotope fractionation for stable carbon isotopes of CFC-11 and CFC-12 in laboratory experiments using broadband UV-C (190-230 nm) light. 13C/12C isotope fractionations (e) range from (-23.8±0.9) to (-17.7±0.4) ‰ for CFC-11 and (-66.2±3.1) to (-51.0±2.9) \permil for CFC-12 between 203 and 288 K, a temperature range relevant to conditions in the troposphere and stratosphere. These results suggest that CFCs should become strongly enriched in 13C with decreasing mixing ratio in the stratosphere, similar to what has been ...
Abstract. For the retrieval of atomic oxygen via ozone observations in the extended mesopause region under sunlight conditions, two assumptions are used: first, the photochemical equilibrium of ozone and, second, that the ozone losses are dominated by ozones dissociation from solar UV radiation, silently ignoring the O3 destruction by atomic hydrogen. We verify both by 3-D modeling. We found that ozone approaches photochemical equilibrium at 75-100 km for daytime conditions. Hence, the first assumption is valid. However, the reaction of ozone with atomic hydrogen was found to be an important loss process and should not be omitted in retrieving atomic oxygen.. ...
Carbon dioxide is the most important greenhouse gas released to the atmosphere through human activities. It is also influenced by natural exchange with the land and ocean. This visualization provides a high-resolution, three-dimensional view of global atmospheric carbon dioxide concentrations from September 1, 2014 to August 31, 2015. The visualization was created using output from the GEOS modeling system, developed and maintained by scientists at NASA. The height of Earths atmosphere and topography have been vertically exaggerated and appear approximately 400 times higher than normal to show the complexity of the atmospheric flow. Measurements of carbon dioxide from NASAs second Orbiting Carbon Observatory (OCO-2) spacecraft are incorporated into the model every 6 hours to update, or
Oxygenated volatile organic compounds ((O)VOCs) contribute to ozone formation, affect the oxidising capacity of the troposphere and are sources of growth, and in some cases formation, of aerosols. It is therefore important to identify and quantify sources of (O)VOCs in the troposphere. In the late 1990s a unique technique for quantification of organic trace gas species, proton transfer reaction mass spectrometry (PTR-MS) was developed. PTR-MS potentially offers rapid response and high sensitivity without the need for sample preconcentration. Concentrations can be derived from the PTR-MS either by calibration or can be calculated from measured ion count rates and kinetic considerations. In this work, the methodology of PTR-MS application is critically assessed. The uncertainties and inaccuracies associated with each parameter employed in the calculation of concentrations are reviewed. This includes a critical appraisal of models for the calculation of the collisional rate constant currently ...
The Atmosphere as a Sensor (AtmoSense) program is a fundamental science program that seeks to understand the propagation of mechanical and electromagnetic energy from the surface of the Earth through the Earths ionosphere due to transient events such as meteorological sources, geophysical sources, prompt hazards, etc. For example, an event on the surface of the Earth, such as a volcanic eruption, will produce radially outward longitudinal mechanical perturbations on the atmosphere. Those wave components travelling radially away from the center of the Earth will encounter decreasing air density with altitude thus reducing the amount of energy transferred to the atmosphere. This energy can propagate all the way to the bottomside of the ionosphere and has been detailed in the observational literature using various electromagnetic measuring techniques. AtmoSense seeks to understand the evolution of this energy through the troposphere, stratosphere, and mesosphere (before it reaches the ...
Atmospheric nitrogen may be a necessary ingredient for the habitability of a planet since its presence helps to prevent water loss from a planet. The present day nitrogen isotopic ratio, 15N/14N, in the Earths atmosphere is a combination of the primitive Earths ratio and the ratio that might have been delivered in comets and asteroids. Asteroids have a nitrogen isotopic ratio that is close to the Earths. This indicates either a similar formation environment to the Earth or that the main source of nitrogen was delivery by asteroids. However, according to geological records, the Earths atmosphere could have been enriched in 15N during the Archean era. Comets have higher a 15N/14N ratio than the current atmosphere of the Earth and we find that about 5% ∼ 10% of nitrogen in the atmosphere of the Earth may have been delivered by comets to explain the current Earths atmosphere or the enriched 15N Earths atmosphere. We model the evolution of the radii of the snow lines of molecular nitrogen and ...
Atmospheric nitrous oxide (N2O) significantly impacts Earths 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 ...
Fine particulate matter (PM2.5) is known to have an adverse impact on public health and is an important climate forcer. Secondary organic aerosol (SOA) contributes up to 80% of PM2.5 worldwide and multiphase reactions are an important pathway to form SOA. Aerosol-phase state is thought to influence the reactive uptake of gas-phase precursors to aerosol particles by altering diffusion rates within particles. Current air quality models do not include the impact of diffusion-limiting organic coatings on SOA formation. This work examines how α-pinene-derived organic coatings change the predicted formation of SOA from the acid-catalyzed multiphase reactions of isoprene epoxydiols (IEPOX). A box model, with inputs provided from field measurements taken at the Look Rock (LRK) site in Great Smokey Mountains National Park during the 2013 Southern Oxidant and Aerosol Study (SOAS), was modified to incorporate the latest laboratory-based kinetic data accounting for organic coating influences. Including an ...
In the journal Nature, paleoclimate researchers reveal that about 12-5 million years ago climate was decoupled from atmospheric carbon dioxide concentrations. In the last five million years, changes in ocean circulation allowed Earths climate to become more closely coupled to changes in carbon dioxide concentrations in the atmosphere.
After reviewing evolutionists speculations on the origin of life, Clemmey and Badham say, ... the dogma has arisen that Earths early atmosphere was anoxic,...1 By anoxic they mean an atmosphere without free oxygen gas (O2), very different from the oxidizing mixture we breathe. The generally accepted model for the evolution of the atmosphere2 supposes that before about 1.9 billion years ago the earths atmosphere was a reducing mixture of nitrogen (N2), methane (CH4), water vapor (H2O), and possibly ammonia (NH3). Solar radiation and lightning discharges into the reducing gas mixture are believed by the consensus of evolutionists to have produced natural organic compounds and eventually life itself. The reason evolutionists postulate an anoxic and reducing atmosphere is mentioned by Miller and Orgel, We believe that there must have been a period when the earths atmosphere was reducing, because the synthesis of compounds of biological interest takes place only under reducing ...
One can see from Table 1 that in the Earths atmosphere molecular nitrogen has the greatest relative concentration near the Earths surface. The effective molecular weight of air is thus rather close to that of this constituent (the two values are 28.973 and 28.022, respectively). However, the composition of the air and consequently its molecular weight are constant only in the lower 80-100 km layer of the atmosphere which is termed the hoinosphere. Above this layer the so-called heterosphere.... ...
article{5c279b19-b4cf-4757-b11a-9043da898f3c, abstract = {A new hygroscopic tandem differential mobility analyzer (H-TDMA) has been constructed at Lund University within the frameworks of the EU FP6 Infrastructure Project EUSAAR (www.eusaar.org). The aim of this coordinated H-TDMA development is to design and evaluate a new generation of H-TDMAs that are capable of conducting long term measurements of the hygroscopic growth and state of mixing of sub-micrometer atmospheric aerosol particles at the EUSAAR aerosol super-sites across Europe. The H-TDMA constructed for this project has been validated with respect to hygroscopic growth factor, stability of relative humidity (RH), temperature stability and its ability to operate unattended for longer periods of time. When measuring growth factors of ammonium sulphate, the new H-TDMA system was found to measure within a growth factor deviation of +/- 0.05 compared to previously recorded data by Tang et al. (1994). The long term RH of the system has ...
Uptake of atmospheric carbon dioxide in the subpolar North Atlantic Ocean declined rapidly between 1990 and 2006. This reduction in carbon dioxide uptake was related to warming at the sea surface, which-according to model simulations-coincided with a reduction in the Atlantic meridional overturning circulation. The extent to which the slowdown of this circulation system-which transports warm surface waters to the northern high latitudes, and cool deep waters south-contributed to the reduction in carbon uptake has remained uncertain. Here, we use data on the oceanic transport of volume, heat and carbon dioxide to track carbon dioxide uptake in the subtropical and subpolar regions of the North Atlantic Ocean over the past two decades. We separate anthropogenic carbon from natural carbon by assuming that the latter corresponds to a pre-industrial atmosphere, whereas the remaining is anthropogenic. We find that the uptake of anthropogenic carbon dioxide-released by human activities-occurred almost ...