A. R. Ravishankara

Bio: A. R. Ravishankara is an academic researcher from National Oceanic and Atmospheric Administration. The author has contributed to research in topics: Reaction rate constant & Kinetics. The author has an hindex of 41, co-authored 88 publications receiving 5129 citations. Previous affiliations of A. R. Ravishankara include Cooperative Institute for Research in Environmental Sciences & University of Colorado Boulder.

Application of optical techniques to studies of kinetics and photochemistry - Tropospheric fate of Methyl Vinyl Ketone and Methacrolein

Abstract: This paper evaluates pulsed photolysis techniques for studying gas-phase radical-molecule reactions that are important in atmospheric chemistry. Reactions of OH are discussed. The pulsed photolysis-pulsed laser induced fluorescence (PP-PLIF) technique is described and compared with other detection techniques. As an example of application of this technique the kinetics of the OH reaction with Methyl Vinyl Ketone (MVK) and Methacrolein (MACR) over the temperature range 232-378 K are presented. Measurements of the UV absorption cross sections of MVK and MACR over the wavelength range 190-450 nm using a diode array spectrometer are also described. These data are used to calculate the tropospheric lifetimes of MVK and MACR.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The air we breathe: Past, present, and future: general discussion.

Abstract: Scott Archer-Nicholls, Alexander Archibald, Stephen Arnold, Thorsten Bartels-Rausch, Steven Brown, Lucy J. Carpenter, William Collins, Luke Conibear, Ruth Doherty, Rachel Dunmore, Jacinta Edebeli, Morgan Edwards, Mathew Evans, Barbara FinlaysonPitts, Jacqueline Hamilton, Meredith Hastings, Colette Heald, Dwayne Heard, Markus Kalberer, Christopher Kampf, Astrid Kiendler-Scharr, Daniel Knopf, Jesse Kroll, Forrest Lacey, Jos Lelieveld, Eloise Marais, Jennifer Murphy, Olajide Olawoyin, A. Ravishankara, Jonathan Reid, Yinon Rudich, Drew Shindell, Nadine Unger, Andreas Wahner, Timothy J. Wallington, Jonathan Williams, Paul Young and Alla Zelenyuk

Rate coefficients for the reaction of OH with OClO between 242 and 392 K

Abstract: Rate coefficients are reported for the gas phase reaction of OH with OClO over the temperature range 242–392 K at 25, 50, and 100 Torr (He). Kinetic measurements were made using pulsed laser photolysis with laser induced fluorescence detection of the OH radical. The measured rate coefficients were independent of pressure and are well represented by k1(T) = (1.43 ± 0.3) × 10−12 exp(597 ± 36/T) cm3 molecule−1 s−1 (k1(298 K) = 1.06 × 10−11 cm3 molecule−1 s−1). The quoted uncertainties are 2σ (95% confidence level) and include estimated systematic errors. Discrepancies with the previous OH + OClO rate coefficient measurement by Poulet et al. (Int J Chem Kinet 1986, 18, 847–859) are discussed. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 234–241, 2006

The HITRAN 2008 molecular spectroscopic database

Abstract: 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.

Climate Change 2007: The Physical Science Basis.

Abstract: 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.

Anthropogenic and Natural Radiative Forcing

Abstract: 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)