Larry M. McMillin

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The Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU) and the HSB (Humidity Sounder Brazil) form an integrated cross-track scanning temperature and humidity sounding system on the Aqua satellite of the Earth Observing System (EOS). AIRS is an infrared spectrometer/radiometer which covers the 3.7 15.4 μm spectral range with(More)
The Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit/Humidity Sounder for Brazil (AIRS/AMSU/HSB) instrument suite onboard Aqua observes infrared and microwave radiances twice daily over most of the planet. AIRS offers unprecedented radiometric accuracy and signal to noise throughout the thermal infrared. Observations from the combined suite of(More)
A fast and accurate method for the generation of atmospheric transmittances, optical path transmittance (OPTRAN), is described. Results from OPTRAN are compared with those produced by other currently used methods. OPTRAN produces transmittances that can be used to generate brightness temperatures that are accurate to better than 0.2 K, well over 10 times as(More)
Improvements to a fast and accurate transmittance-calculation procedure, Optical Path TRANsmittance (OPTRAN), are described. The previous version computed a transmittance ratio for an absorbing layer. It required special attention to the interpolation methodology. The new approach reported here computes the absorption coefficient for an absorbing layer.(More)
Models exist which allow the calculation of atmospheric transmittance at a given zenith angle for an absorbing gas with a constant mixing ratio. However, many applications require transmittances at several zenith angles. A simple, fast, and accurate model for calculating the angular dependence is given. This model is computationally fast because only the(More)
An approach to approximating the instrument response for an unapodized interferometer is presented. The approach comprises functions that are local enough in frequency space (no more than five wave numbers) that one can use the Planck function at a single frequency to calculate the radiance at a given frequency and atmospheric pressure level, and it is well(More)
Atmospheric transmittance models for absorbing gases with constant mixing ratios were described in the two preceding papers of this series. In this paper a method for calculating atmospheric transmittances for absorbing gases with variable mixing ratios is described. Because the model uses only arithmetic operations, it is computationally fast as well as(More)
Since the publication of the Optical Path Transmittance (OPTRAN) algorithm [Appl. Opt. 34, 8396 (1995)], much of the code and implementation has been refined and improved. The predictor set has been expanded, an objective method to select optimal predictors has been established, and the two-interpolation method has been discarded for a single-interpolation(More)