Since 2017 the Juno spacecraft has observed a cyclone at the north pole of Jupiter surrounded by eight smaller cyclones arranged in a polygonal pattern. It is not clear why this configuration is so stable or how it is maintained. Here we use a time series of images obtained by the JIRAM mapping spectrometer on Juno to track the winds and measure the vorticity and horizontal divergence within and around the polar cyclone and two of the circumpolar ones. We find an anticyclonic ring between the polar cyclone and the surrounding cyclones, supporting the theory that such shielding is needed for the stability of the polygonal pattern. However, even at the smallest spatial scale (180 km) we do not find the expected signature of convection—a spatial correlation between divergence and anticyclonic vorticity—in contrast with a previous study using additional assumptions about the dynamics, which shows the correlation at scales from 20 to 200 km. We suggest that a smaller size, relative to atmospheric thickness, of Jupiter’s convective storms compared with Earth’s, can reconcile the two studies.

自 2017 年以来，朱诺号宇宙飞船在木星北极观测到一个气旋，周围环绕着八个呈多边形排列的较小气旋。目前尚不清楚为什么此配置如此稳定或如何维护。在这里，我们使用朱诺号上的 JIRAM 映射光谱仪获得的时间序列图像来跟踪风，并测量极地气旋和两个环极气旋内部和周围的涡度和水平散度。我们在极地气旋和周围气旋之间发现了一个反气旋环，支持这样的理论，即多边形图案的稳定性需要这种屏蔽。然而，即使在最小的空间尺度（180 公里），我们也没有发现预期的对流特征——散度和反气旋涡量之间的空间相关性——与之前使用关于动力学的额外假设的研究形成对比，该研究显示了从 20 到 20 尺度的相关性到 200 公里。我们建议，与地球相比，木星的对流风暴的尺寸相对于大气厚度更小，可以调和这两项研究。