Changing characteristics of an anticyclone in Jupiter’s South South South Temperate Current

The longitude and latitude of a white oval (A1) on Jupiter was measured on 83 different visible light images between 2011 Jul 10 and 2012 Jan 19. The average drift rate changed from 0.59°/day to 0.22°/day around 2011 Oct 1. The purpose of this study is to investigate the cause of this change. Two findings are the latitude of A1 moved from 51.0° ± 0.1°S to 50.0° ± 0.1°S and the north-to-south dimension of A1 rose from 2.1° ± 0.1° to 2.5° ± 0.1° near the time the drift rate changed. A dark oval (A30) may have interacted with A1 near this time. It is concluded the latitude change led to the drift rate change. The change in shape or the interaction with oval A30 may have led to the latitude change. A1 oscillated in longitude with an amplitude of ~5° over a period of ~80 days.

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