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N. E. Bowles, S. B. Calcutt, P. G. J. Irwin, J. M. Temple (Clarendon Laboratory, University of Oxford)
This paper details new measurements and modelling of low-resolution transmittance spectra of ammonia gas, one of the most important absorbers found in the near-infrared spectrum of the planet Jupiter. The new spectra were specifically designed to support measurements of Jupiter’s atmosphere made by the Near-Infrared Mapping spectrometer (NIMS) which was part of the Galileo mission that orbited Jupiter from 1995 to September 2003. To approximate Jovian conditions in the lab a new gas spectroscopy facility was developed. This new facility was then used to measure ammonia spectra from 0.75 to 5.3 microns (virtually the complete range covered by NIMS), with temperatures varying from 300 to 215K, pressures from 1000 to 33mb and using three different path lengths (10.164, 6.164 and 2.164m). The measured spectra were then compared with spectra using existing spectral data (e.g. the HITRAN2000 line database). Finally, they were used to derive transmittance functions by fitting a variety of physically based band models, which were then used to generate k coefficients. This allowed the newly measured spectral parameters to applied to NIMS remote sensing by using radiative transfer calculations that include the scattering effects of haze and cloud particles
This work was supported by the UK Particle Physics and Astronomy Research Council.
The author(s) of this abstract have provided an email address for comments about the abstract: bowles@atm.ox.ac.uk
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.