Publications

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, 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. 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...

Weinstock, E. M., et al. (2007), Quantifying the impact of the North American monsoon and deep midlatitude convection on the subtropical lowermost stratosphere using in situ measurements, J. Geophys. Res., 112, D18310, doi:10.1029/2007JD008554.

The chemical composition of the lowermost stratosphere exhibits both spatial and temporal variability depending upon the relative strength of (1) isentropic transport from the tropical tropopause layer (TTL), (2) diabatic descent from the midlatitude and northern midlatitude stratosphere followed by equatorward isentropic transport, and (3) diabatic ascent from the troposphere through convection...

Leroy, S. S., and J. G. Anderson (2007), Estimating Eliassen-Palm flux using COSMIC radio occultationGeophys. Res. Lett.,34, L10810, doi:10.1029/2006GL028263.

We present a methodology for analyzing the Eliassen-Palm (E-P) flux in the troposphere and stratosphere using GPS radio occultation data from the COSMIC project. In this methodology, geopotential height and temperature are mapped on constant pressure surfaces using a Bayesian interpolation scheme with a spherical harmonic basis, and the components of the E-P flux are evaluated using geostrophic...

Pittman, J. V., et al. (2007), Transport in the subtropical lowermost stratosphere during the Cirrus Regional Study ofTropical Anvils and Cirrus Layers – Florida Area Cirrus Experiment, J. Geophys. Res., 112, D08304, doi:10.1029/2006JD007851.

We use in situ measurements of water vapor (H2O), ozone (O3), carbon dioxide(CO2), carbon monoxide (CO), nitric oxide (NO), and total reactive nitrogen (NOy)obtained during the CRYSTAL-FACE campaign in July 2002 to study summertimetransport in the subtropical lowermost stratosphere. We use an objective methodology todistinguish the latitudinal origin of the sampled air masses despite the...

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...

Revercomb, H. E., Anderson, J. G., Best, F. A., Tobin, D. C., Knuteson, R. O., LaPorte, D.D., and Taylor, J. K.: Infrared calibration for climate: A perspective on present and future high spectral resolution instruments, Multispectral, Hyperspectral, and Ultraspectral RemoteSensing Technology, Techniques, and Applications, Gao, India, 13–16 November 2006.

The new era of high spectral resolution infrared instruments for atmospheric sounding offers great opportunities for climate change applications.  A major issue with most of our existing IR observations from space is spectral sampling uncertainty and the lack of standardization in spectral sampling.  The new ultra resolution observing capabilities from the AIRS grating...

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...

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