نتایج جستجو برای: atmospheric lifetime

تعداد نتایج: 131217  

2006
David Archer Victor Brovkin

The notion is pervasive in the climate science community and in the public at large that the climate impacts of fossil fuel CO2 release will only persist for a few centuries. This conclusion has no basis in theory or models of the atmosphere/ocean carbon cycle, which we review here. The largest fraction of the CO2 recovery will take place on time scales of centuries, as CO2 invades the ocean, b...

2002
Michael J. Prather

[1] The environmental damage caused by atmospheric pollutants is proportional to the duration of their effects. The global impacts of greenhouse gases (as measured by global warming potential) and ozone depleting substances (as measured by ozone depletion potential) have traditionally been calculated using the atmospheric lifetime of the source gas as a quantitative measure of the impact’s dura...

2013
M. Rigby John M. Reilly

Since the Montreal Protocol on Substances that Deplete the Ozone Layer and its amendments came into effect, growth rates of the major ozone depleting substances (ODS), particularly CFC-11, -12 and -113 and CH3CCl3, have declined markedly, paving the way for global stratospheric ozone recovery. Emissions have now fallen to relatively low levels, therefore the rate at which this recovery occurs w...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2010
Roland von Glasow

Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as th...

2008
Thomas Coan Tiankuan Liu Jingbo Ye

We describe a compact apparatus that automatically measures the charge averaged lifetime of atmospheric muons in plastic scintillator using low-cost, low-power electronics and that measures the stopping rate of atmospheric muons as a function of altitude to demonstrate relativistic time dilation. The apparatus is designed for the advanced undergraduate physics laboratory and is suitable for fie...

1998
James Stone

This manuscript presents an overview of the current experimental situation regarding nucleon decay and the measured flux of atmospheric neutrinos. Previous and on-going experiments are reviewed, the data are presented, and new outstanding questions are posed. The SuperKamiokande project is described and its expected sensitivity for improving measurements of the nucleon lifetime and the atmosphe...

Journal: :Physical chemistry chemical physics : PCCP 2011
S Xiao A K Bertram

We investigated the reactive uptake of NO(3) (an important night-time oxidant in the atmosphere) on binary mixtures containing an unsaturated organic (methyl oleate) and saturated molecules (diethyl sebacate, dioctyl sebacate, and squalane) which we call matrix molecules. These studies were carried out to better understand the reactivity of unsaturated organics in multicomponent and multiphase ...

2002
James B. Burkholder Mary K. Gilles Tomasz Gierczak A. R. Ravishankara

[1] The atmospheric degradation of 1-bromopropane and its degradation products are examined with respect to their ability to deplete stratospheric ozone. It is shown that the OH initiated oxidation of 1-bromopropane does not lead to long lived bromine containing species. Laboratory measurements of the UV absorption cross sections and photodissociation quantum yields of chloroacetone and bromoac...

Journal: :Environmental science & technology 2006
Cora J Young Michael D Hurley Timothy J Wallington Scott A Mabury

Perfluoropolyethers (PFPEs) are a family of perfluorinated fluids used mainly in industrial applications. Lower molecular weight commercial PFPE fractions have boiling points ranging between 55 and 270 degrees C, and have the potential to escape into the atmosphere. To improve our understanding of the atmospheric chemistry of PFPEs, a distilled fraction of a commercial mixture containing perflu...

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