Publications

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 vaporJ. 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, 2009A new cavity based absorption instrument for detection of water isotopologues in the upper troposphere and lower stratosphereRev. Sci. Instrum.80044102, 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...

Gero P J, Dykema J A and Anderson J G 2008 A blackbody design for SI-traceable radiometry for earth observation J. Atmos. Ocean. Technol. 25 2046–54

Spaceborne measurements pinned to international standards are needed to monitor the earth’s climate,quantify human influence thereon, and test forecasts of future climate change. The International System ofUnits (SI, from the French for Système International d’Unités) provides ideal measurement standards forradiometry as they can be realized anywhere, at any time in the future. The challenge is...

E.J. Moyer, D.S. Sayres, G.S. Engel, J.M.St. Clair, F.N. Keutsch, N.T. Allen, J.H. Kroll, J.G. Anderson, Design considerations in high-sensitivity off-axis integrated cavity output spectroscopy. Phys. B 92, 467 (2008)

CT Off-axis integrated cavity output spectroscopy(OA-ICOS) has generated much interest because it potentially allows highly sensitive field measurements with robustoptical alignment. We discuss here design choices involvedin design of an OA-ICOS instrument and how these choicesimpact instrument sensitivity, using as our example the design of the Harvard ICOS isotope instrument, which demonstrates...

J.M. St. Clair, T.F. Hanisco, E.M. Weinstock, E.J. Moyer,D.S. Sayres, F.N. Keutsch, J.H. Kroll, J.N. Demusz,N.T. Allen, J.B. Smith, J.R. Spackman, J.G. Anderson, A new photolysis laser-induced fluorescence instrument for the detection of H2O and HDO in the lower stratosphere. Sci. Instrum. 79, 064101 (2008). doi:10.1063/1.2940221.

We present a new instrument, Hoxotope, for the in situ measurement of H2O and its heavy deuterium isotopologue (HDO) in the upper troposphere and lower stratosphere aboard the NASA WB-57. Sensitive measurements of δD are accomplished through the vacuum UV photolysis of water followed by laser-induced fluorescence detection of the resultant OH and OD photofragments....

Leroy, S., J. G. Anderson, J. Dykema, and R. Goody (2008), Testing climate models with thermal infrared spectra, J. Clim., 21, 1863–1875.

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...

Sayres, D. S., J. B. Smith, J. V. Pittman, E. M. Weinstock, J. G. Anderson, G. Heymsfield, L. Li, A. M. Fridlind, and A. S. Ackerman(2008), Validation and determination of ice water content-radar reflectivity relationships during CRYSTAL-FACE: Flight requirements for future comparisonsJ. Geophys. Res.113, D05208, doi:10.1029/2007JD008847.

In situ measurements of cirrus ice water content (IWC) by the Harvard water vapor and total water instruments during Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment are compared with remote sensing data made by the Cloud Radar System instrument in order to derive and validate an empirical IWC-radar relflectivity Z e relationship. The...

Leroy, S. S., J. G. Anderson, and G. Ohring (2008), Climate signal detection times and constraints on climate benchmark accuracy requirements,J. Clim., 21, 841 – 846, doi:10.1175/2007JCLI1946.1.

Long term trends in the climate system are always partly obscured by naturally occurring interannual variability.All else being equal, the larger the natural variability is, the less precisely one can estimate a trend in a timeseriesof data. Measurement uncertainty, though, also obscures long term trends. We derive how measurement uncertaintyand natural interannual variability interact in...

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