Abstract
Current high-resolution IR spectroscopy at ground-based observatories made it possible to observe $3-{\mu}m\;CH_4$ emission lines from the atmospheres of Jupiter, Saturn, and Titan through narrow atmospheric windows avoiding the counterparts of telluric $CH_4$ absorptions if proper Doppler shifts betwen Earth and these planetary objects are provided. We are also expecting low-resolution (R~300) infrared spectra of Jupiter from the upcoming observations by JUNO's infrared $2-5{\mu}m$ spectrograph during the encounter with Jupiter approximately starting from July 4, 2016. Although the spectral resolution is not enough to resolve the $3-{\mu}m$ P, Q, R branch lines of CH4, the gross envelopes of the P, Q, R branches should yield information on rotational temperatures. The rotational temperatures are useful because theycan be regarded as local temperatures, as discussed by Kim et al. (2014). Since the $3-{\mu}m\;CH_4$ emission is mostly formed at micro-bar pressure levels, the derived rotational temperatures represent the local temperatures near the hompause of Jupiter. We discuss possible sciences from the derived homopause temperatures in the auroral and non-auroral regions of Jupiter.