Jupiter's Tropospheric Thermal Emission. I. Observations and Techniques

• Published in: Icarus (New York, N.Y. 1962) N.Y. 1962), 1996-11, Vol.124 (1), p.22-31
• Main Authors: Harrington, Joseph, Dowling, Timothy E., Baron, Richard L.
• Format: Article
• Language: English
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1006/icar.1996.0187

This paper presents a new Jupiter data set and several new techniques developed for its reduction. A companion paper (J. Harrington, T. E. Dowling, and R. L. Baron, 1996,Icarus124, 32–44) uses these data to study the scales of energy deposition into Jupiter's atmosphere. We observed Jupiter's tropospheric thermal emission at a wavelength of 4.9 μm (1% bandpass) with the NASA Infrared Telescope Facility (Mauna Kea, HI). The ProtoCAM 62 × 58-pixel infrared array camera took a total of 229 full-disk 3 × 3- and 4 × 4-image mosaics on 19 nights spanning the period 11 Jan. through 19 Apr. 1992. Resolution was typically 0.5″–0.75″. We obtained full longitude coverage on six nights. This wavelength is sensitive to emission from the ∼5-bar level, near the top of the (putative) jovian water cloud level. Clouds located higher in the atmosphere attenuate this emission. The images show atmospheric structure at all resolved spatial scales and have a cloud optical depth range of ∼4.6. We developed image processing techniques for finding the optimal registration of images in mosaics and for locating low-contrast planetary limbs in images of planets with many high-contrast features. Both techniques are new and generally applicable and require no human interaction.