Recent laboratory measurements of the absorption cross sections of the ClO dimer, ClOOCl, have called into question the validity of the mechanism that describes the catalytic removal of ozone by chlorine. Here we describe direct measurements of the rate-determining step of that mechanism, the production of Cl atoms from the photolysis of ClOOCl, under laboratory conditions similar to those in the...
James G. Anderson's Publications
Wilmouth, D.M., T.F. Hanisco, R.M. Stimpfle, and J.G. Anderson, Chlorine-Catalyzed Ozone Destruction: Cl Atom Production from ClOOCl Photolysis, J. Phys. CHem. A, 113, 14099-14108, doi:10.1021/JP9053204, 2009.
Sayres, D.S., E.J. Moyer, T.F. Hanisco, J.M. Clair, F.N. Keutsch, A. O’Brien, N.T. Allen, L.Lapson, J.N. Demusz, M. Rivero, T. Martin, M. Greenberg, C. Tuozzolo, G.S. Engel, J.H. Kroll, J.B. Paul, and J.G. Anderson, A New Cavity Based Absorption Instrument for Detection of Water Isotopologues in the Upper Troposphere and Lower Stratosphere, Review of Scientific Instruments, 80, 2009.
We describe here the Harvard integrated cavity output spectroscopy (ICOS) isotope instrument, a mid-IR infrared spectrometer using ICOS to make in situ measurements of the primary isotopologues of water vapor (H2O, HDO, and H218O) in the upper troposphere and lower stratosphere (UTLS). The long path length provided by ICOS provides the sensitivity and accuracy necessary to measure...
Leroy, S.S., Y. Huang, and J.G. Anderson, Radio Occulation Data: Its Utility in NWP and Climate Fingerprinting, Proceedings of ECMWF Seminar on Diagnosis of Forecasting and Data Assimilation Systems, 7-10, September 2009.
Radio occultation data: Its utility in NWP and climate fingerprinting. Presentation at ECMWY 2009 Annual Seminar — Seminar on Diagnosis of Forecasting and Data Assimilation Systems, 7 - 10 September 2009.(http://www.ecmwf.int/newsevents/meetings/annual_seminar/2009/presentations.html)
Yi-wen Huang, Timothy J. Dransfield, Jeremy D. Miller, Ronny D. Rojas, Xavier G. Castillo, and James G. Anderson. Experimental Study of the Kinetics of the Reaction of Acetic Acid with Hydroxyl Radicals from 255 to 355 K.The Journal of Physical Chemistry A 2009 113 (2), 423-430
The rate constant of the reaction of OH with acetic acid over the temperature range of 255-355 K was determined using our High-Pressure Flow System with laser-induced fluorescence detection of the OH radicals and FTIR spectrometry for acetic acid quantification. The rate constant displays a negative temperature dependence and can be described by the Arrhenius expression: k(1)(T) = (5.38 +/- 0.28...
Weinstock, E. M., et al. (2009), Validation of the Harvard Lyman-α in situ water vapor instrument: Implications for the mechanisms that control stratospheric water vapor, J. Geophys. Res., 114, D23301, doi:10.1029/2009JD012427.
Building on previously published details of the laboratory calibrations of the Harvard Lyman-α photofragment fluorescence hygrometer (HWV) on the NASA ER-2 and WB-57 aircraft, we describe here the validation process for HWV, which includes laboratory calibrations and intercomparisons with other Harvard water vapor instruments at water vapor mixing ratios from 0 to 10 ppmv, followed by in-...
Mark F. Witinski, Joshua B. Paul, and James G. Anderson, "Pump-enhanced difference-frequency generation at 3.3 μm," Appl. Opt. 48, 2600-2606 (2009)
The demonstration of continuous wave intracavity difference-frequency generation in the mid-infrared (mid-IR) is presented. A cavity for pump laser enhancement is constructed around a periodically poled lithium niobate crystal, and the cavity length is locked to the frequency of the pump laser using the Pound-Drever-Hall technique, producing a gain of 12 in the resultant idler power compared to...
Sayres, D. S., and Coauthors, 2009: A new cavity based absorption instrument for detection of water isotopologues in the upper troposphere and lower stratosphere. Rev. Sci. Instrum., 80, 044102, doi:10.1063/1.3117349.
We describe here the Harvard integrated cavity output spectroscopy (ICOS) isotope instrument, a mid-IR infrared spectrometer using ICOS to make in situ measurements of the primary isotopologues of water vapor (H2O, HDO, and H218O) in the upper troposphere and lower stratosphere (UTLS). The long path length provided by ICOS provides the sensitivity and accuracy necessary to measure...
Sprengnether MM, Demerjian KL, Dransfield TJ, Clarke JS, Anderson JG, Donahue NM.J Phys Chem A. 2009 Apr 30;113(17):5030-8.
We report absolute rate-constant measurements for the reactions of nine C(6)-C(9) alkanes with OH in 8-10 torr of nitrogen from 230 to 379 K in the Harvard University High-Pressure Flow System. Hydroxyl concentrations were measured using laser-induced fluorescence, and alkane concentrations were measured using Fourier transform infrared Spectroscopy. Ethane's reactivity was simultaneously...
Leroy, Stephen, James Anderson, John Dykema, Richard Goody, 2008: Testing Climate Models Using Thermal Infrared Spectra. J. Climate, 21, 1863–1875. doi: http://dx.doi.org/10.1175/2007JCLI2061.1
An approach to test climate models with observations is presented. In this approach, it is possible to directly observe the longwave feedbacks of the climate system in time series of annual average outgoing longwave spectra. Tropospheric temperature, stratospheric temperature, water vapor, and carbon dioxide have clear and distinctive signatures in the infrared spectrum, and it is possible to...
Leroy, S.S., J.A. Dykema, and J.G. Anderson, “Scalar prediction in climate using data and model,” Submitted to J. Climate (2008).
Scalar detection in climate change research, having taken the form of optimal detection/linear multi-pattern regression, has been used in the recent past to detect multiple climate signals in the presence of natural inter- annual variability and associate those signals with specific causes. It has been applied to many climate observables to show high probabilities of human influence on climatic...