Models of bright storm clouds and related dark ovals in Saturn’s Storm Alley as constrained by 2008 Cassini/VIMS spectra

摘要

Highlights?Saturn’s storm alley (33–39°S) was active in 2008 when observed by VIMS.?Radiation transfer models of VIMS spectra lead to a plausible scenario.?Storm clouds are deep ammonia clouds partly penetrating a ubiquitous top layer.?After convection stops, large particles fall out, leaving an eroded top layer.?Dark ovals are regions where the top layer has half its original optical depth.AbstractA 5° latitude band on Saturn centered near planetocentric latitude 36°S is known as “Storm Alley” because it has been for several extended periods a site of frequent lightning activity and associated thunderstorms, first identified by Porco et?al. (2005). The thunderstorms appeared as bright clouds at short and long continuum wavelengths, and over a