Extended Data Figure 1 : Comparison of the polar cyclonic structures between PJ4 and PJ5.

From: Clusters of cyclones encircling Jupiter’s poles

Extended Data Figure 1

Here is the comparison between JIRAM 5-μm data acquired during PJ4 and PJ5. The letters identify possible recurrent structures and arrows show the suggested displacements that occurred in the 53-day interval between these two perijoves. The radiance scale is the same as in Fig. 1. When the region surrounding the north pole is not sunlit, there are no JunoCam observations of the NPC. Although the north pole was detected by JIRAM on PJ4, we were unable to determine whether or not it maintains a stable position over the geographic north pole because of insufficient coverage of the NPC during PJ5. However, the cyclonic structures A, B and C move northeast, migrating from the lower latitudes. The G and H internal structures, located between the NPC and the cyclones, are anticyclones and move westward in that narrow corridor between 85.5° N and 87° N to their new location observed during PJ5 between vortex D and the NPC. In contrast, JIRAM was able to observe the SPC in both PJ4 and PJ5. In fact, along with the cyclones G and H shown, the SPC moves northward, increasing its distance with respect to the geographic south pole by 1.5° between PJ4 and PJ5. On the other hand, JunoCam was able to observe the SPC at all perijoves, and found that it was always displaced from the south pole in approximately the same direction (towards a System III longitude of about 219° ± 21°), with its central latitude varying from 88.0° S at PJ1 up to 89.0° S at PJ4, and down to 88.4° S at PJ5. It remains to be seen whether this is a cyclic oscillation. The five cyclones remain at almost constant radial distances from the centre of the SPC (and thus not from the geographic south pole), so the whole pentagon drifts in latitude. Anticyclone A appears to move as much as about 1° south and about 24° east. It is forced and surrounded by the two cyclonic structures that consolidate themselves between PJ4 and PJ5 from the origins L, J, C and K. Finally, the anticyclone D disappears while F is expelled from its position and possibly moves to new position E.