Optical bandpass-filter observations can be simply processed to determine
similar horizontal ammonia distributions above the Jovian cloud tops as
mid-infrared and microwave observations. Current understanding of this
distribution and its relationship to aerosol opacity, cloud-top pressure, and
circulation is provided by atmospheric retrieval models using observations from
major ground-based facilities and spacecraft. These techniques recover high
fidelity information on the ammonia distribution but are limited in spatial and
temporal coverage. Part of this coverage gap - upper tropospheric abundance -
can be bridged by using continuum-divided ammonia and methane absorption images
as suggested by Combes and Encrenaz [1979]. In 2020-21, Jupiter was imaged in
the 645 nm ammonia absorption band and adjacent continuum bands, demonstrating
that the spatially-resolved optical depth in that band could be determined with
a 0.28-m Schmidt-Cassegrain telescope (SCT). In 2022, a 620 nm filter was added
to include methane absorption images in the same wavelength range. Methane
abundance provides a constant reference against which to determine the ammonia
abundance, specifically the column-averaged mole fraction above the clouds.
VLT/MUSE results are compared to these SCT results and those from the TEXES
mid-infrared spectrometer used on the IRTF and the Gemini telescopes.
Meridional and longitudinal features are examined, including the Equatorial
Zone (EZ) ammonia enhancement, the North Equatorial Belt (NEB) depletion,
depletion above the Great Red Spot (GRS), and suggested enhancements over
bright plumes in the northern EZ. This work demonstrates meaningful ammonia
monitoring that can provide synoptic coverage and continuity between spacecraft
or major ground-based facility campaigns.Comment: 23 pages, 8 figure