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J. Harrington (Cornell), D. Deming (NASA/GSFC), A. Ruane, S. Vatanavigkit (Cornell)
We have obtained high signal-to-noise ratio, 360-degree thermal maps of Jupiter's troposphere and stratosphere on 16 nights over 3 years leading up to the Cassini encounter with Jupiter. The spacing of observations optimizes the measurement of motions in the 0--500 m/sec range at high planetary wavenumbers. We present the first-ever maps of the fraction of para-H2 and report the detection of multiple waves (m~13 and m=1 at 18 degrees S), local stratospheric heat deposition and advection that is likely due to breaking vertical waves (15 degrees N), and the apparent disappearance of the belt-zone structure poleward of ~25 degrees N and S. The observations were acquired with the MIRLIN camera at the NASA Infrared Telescope Facility on 1998 Oct. 11, 12, 20, 21; 1999 Dec. 7, 8, 17, 18, 30, 31; 2000 Dec. 14, 15, 20, 21; and 2001 Jan. 4 & 5 UT. The final 6 dates corresponded to the Cassini encounter, and the final date coincides with Cassini Composite Infrared Spectrometer (CIRS) mapping observations. Observations sense the temperatures of stratospheric (~ 1 mbar) CH4 with a 2% 7.85-micron circular variable filter and tropospheric (~ 300 mbar) H2 with the discrete Q2 (18.64± 0.26 microns) and Q3 (20.81± 0.83 microns) filters. These wavelengths are minimally affected by aerosols, so image intensity is directly related to temperature. With up to 279 background-limited measurements per point, these maps exceed the CIRS maps in spatial resolution and signal-to-noise ratio for local thermal comparisons (e.g., wave studies). Used together, simultaneously-acquired CIRS maps provide an absolute calibration precluded by the variability of terrestrial atmospheric thermal emission, while the MIRLIN maps provide a higher-spatial-resolution context for CIRS's multi-wavelength coverage, particularly in its long-wavelength channel. Work funded by the NASA Planetary Astronomy program.