Frank Keutsch's Publications

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...

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...

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....

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...

Hanisco, T. F., et al. (2007), Observations of deep convective influence on stratospheric water vapor and its isotopic compositionGeophys. Res. Lett.34, L04814, doi:10.1029/2006GL027899.

In situ observations of H2O and HDO in the midlatitude stratosphere are used to evaluate the role of convection in determining the stratospheric water budget. The observations show that water vapor in the overworld stratosphere (potential temperature > 380 K) is isotopically heavier than expected. Measurements in an airmass with anomalously high concentrations of water vapor show isotopic...

Gregory S. Engel, Walter S. Drisdell, Frank N. Keutsch, Elisabeth J. Moyer, and James G. Anderson, "Ultrasensitive near-infrared integrated cavity output spectroscopy technique for detection of CO at 1.57 μm: new sensitivity limits for absorption measurements in passive optical cavities," Appl. Opt. 45, 9221-9229 (2006) 

A robust absorption spectrometer using the off-axis integrated cavity output spectroscopy (ICOS) technique in a passive cavity is presented. The observed sensitivity, conceptually the detection threshold for the absorption cross section (cm2) multiplied by the concentration (cm−3) and normalized by the averaging time, is measured to be 1.9×10−12 (1/cm√Hz). This high sensitivity arises from...