Variability of Saturn's Equatorial Zonal Winds at Cloud Level Between 2018 and 2025

Abstract

Abstract Saturn's zonal wind profile at cloud level has been measured at different epochs since the Voyager 1 and 2 in 1980–81. At most latitudes, zonal winds change little over time. However, the equatorial region, between planetographic latitudes 10°N and 10°S, presents a complex vertical structure and significant variability. Here, we measure zonal winds in Saturn's atmosphere over 8 years (2018–2025) at two different tropospheric levels (about 50 and 500 mbar). We used Hubble Space Telescope images to derive wind profiles through zonal brightness correlation techniques. The results provide measurements during Saturn's northern summer, thereby extending the available record and enabling comparisons across multiple years. We report temporal variability of the wind profiles and find that the narrow equatorial jet observed between 2004 and 2015 in the upper troposphere disappeared between 2018 and 2025.