Deep Clouds on Jupiter

Deep clouds on Jupiter are seen in cyclonic vortices, convective storms, and over a broad high-latitude expanse beyond 45 degrees north. Time-series Hubble imaging, combined with Juno lightning detections, shows that these deep clouds are often associated with convective storms, but they can linger after convection concludes, or appear before it starts. The deep clouds at high latitudes are seen because there is a widespread thinning out of the overlying cloud deck (based on modeling of the HST data combined with simultaneous Gemini infrared imaging). A chemical model of the upper clouds finds that the expected ammonia and ammonium hydrosulfide clouds should form above and below a cloud-free "dead zone" in the 1-2 bar pressure range. The Galileo probe and several remote sensing publications over the years have found cloud opacity within this dead zone, challenging our knowledge of giant planet cloud chemistry. Deep clouds have been used in previous work to estimate the atmospheric water abundance, but because the deep atmospheric temperatures are not precisely known, this method can only be used to show that the water abundance must be at least 0.5 times the solar value.

Speaker: Mike Wong, UC Berkeley and SETI Institute