This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.

/pdf/the-hitran-2008-molecular-spectroscopic-database-1ud8clpej3.pdf

The HITRAN 2008 molecular spectroscopic database

Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

/pdf/climate-change-2007-the-physical-science-basis-1x93ttz9jt.pdf

Climate Change 2007: The Physical Science Basis.

This chapter should be cited as: Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Coordinating Lead Authors: Gunnar Myhre (Norway), Drew Shindell (USA)

Anthropogenic and Natural Radiative Forcing

http://joenschem.com/yahoo_site_admin/assets/docs/atkinson2000r.93190106.pdf

Atmospheric chemistry of VOCs and NOx

Atmospheric degradation of volatile organic compounds

Ozone depletions in the lower stratosphere outside of polar regions are difficult to explain using only local chlorine and bromine chemistry. We speculate that iodine chemistry in combination with trends in anthropogenic chlorine and bromine may also be a factor in determining the widespread current depletion of lower stratospheric ozone. We also speculate on a related role for iodine in the sudden springtime surface ozone loss observed in the Arctic.

On the role of iodine in ozone depletion

A framework for applying rates of heterogeneous chemical reactions measured in the laboratory to small sulfuric acid aerosols found in the stratosphere is presented. The procedure for calculating the applicable reactive uptake coefficients using laboratory-measured parameters is developed, the necessary laboratory-measured quantities are discussed, and a set of equations for use in models are presented. This approach is demonstrated to be essential for obtaining uptake coefficients for the HOCl + HCl and ClONO2 + HCl reactions applicable to the stratosphere. In these cases the laboratory-measured uptake coefficients have to be substantially corrected for the small size of the atmospheric aerosol droplets. The measured uptake coefficients for N2O5 + H2O and ClONO2 + H2O as well as those for other heterogeneous reactions are discussed in the context of this model. Finally, the derived uptake coefficients were incorporated in a two-dimensional dynamical and photochemical model thus for the first time the HCl reactions in sulfuric acid have been included. Substantial direct chlorine activation and consequent ozone destruction is shown to occur due to heterogeneous reactions involving HCl for volcanically perturbed aerosol conditions at high latitudes. Smaller but significant chlorine activation also is predicted for background aerosol loadings at extreme high latitudes, suggesting chlorine activation can occur on background sulfuric acid aerosol in these regions. The coupling between homogeneous and heterogeneous chemistry is shown to lead to important changes in the concentrations of various reactive species. The basic physical and chemical quantities needed to better constrain the model input parameters are identified.

Heterogeneous reactions in sulfuric acid aerosols: A framework for model calculations

Global atmospheric models play a key role in international assessments of the human impact on global climate and air pollution. To increase the accuracy and facilitate comparison of results from such models, it is essential they contain up-to-date chemical mechanisms. To this end, we present an evaluation of the atmospheric chemistry of the four most abundant organic peroxy radicals: CH3O2, C2H5O2, CH3C(O)O2, and CH3C(O)CH2O2. The literature data for the atmospheric reactions of these radicals are evaluated. In addition, the ultraviolet absorption cross sections for the above radicals and for HO2 have been evaluated. The absorption spectra were fitted to an analytical formula, which enabled published spectra to be screened objectively. Published kinetic and product data were reinterpreted, or in some case reanalyzed, using the new cross sections, leading to a self-consistent set of kinetic, mechanistic, and spectroscopic data. Product studies were also evaluated. A set of peroxy radical reaction rate coefficients and products are recommended for use in atmospheric modeling. A three-dimensional global chemical transport model (the Intermediate Model for the Global Evolution of Species, IMAGES) was run using both previously recommended rate coefficients and the current set to highlight the sensitivity of key atmospheric trace species to the peroxy radical chemistry used in the model.

https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2000JD900746

Atmospheric chemistry of small organic peroxy radicals

A wetted wall flow tube reactor was used to measure the uptake coefficients, γ, of OH and HO 2 on pure water at 275 K and 28% w/w sulfuric acid at 249 K. The uptake coefficients are lower limits to the mass accommodation coefficients, α, and the γ were determined to be 0.0035 for OH and >0.01 for HO 2 on liquid water and >0.08 for OH and >0.05 for HO 2 on the sulfuric and solution. In addition, the binary diffusion coefficients for HO 2 and OH in water vapor were estimated to be 79±8 and 116±20 Torr cm 2 s -1 , respectively, at 275 K

A. R. Ravishankara

Papers

On the role of iodine in ozone depletion

Heterogeneous reactions in sulfuric acid aerosols: A framework for model calculations

Atmospheric chemistry of small organic peroxy radicals

Measurement of hydroxyl and hydroperoxy radical uptake coefficients on water and sulfuric acid surfaces

Reactive Uptake of ClONO2 onto Sulfuric Acid Due to Reaction with HCl and H2O