The Juno mission observed that both poles of Jupiter have polar cyclones that are surrounded by a ring of circumpolar cyclones. The North Pole holds eight circumpolar cyclones and the South Pole possesses five, with both circumpolar rings positioned along latitude ∼ 84 • N/S. Here we explain the location, stability, and number of the Jovian circumpolar cyclones by establishing the primary forces that act on them, which develop because of vorticity gradients in the background of a cyclone. In the meridional direction, the background vorticity varies owning to the planetary sphericity and the presence of the polar cyclone. In the zonal direction, the vorticity varies by the presence of adjacent cyclones in the ring. Our analysis successfully predicts the latitude and number of circumpolar cyclones for both poles, according to the size and spin of the respective polar cyclone. Moreover, the analysis successfully predicts that Jupiter can hold circumpolar cyclones while Saturn currently cannot. The match between the theory and observations implies that vortices in the polar regions of the giant planets are largely governed by barotropic dynamics, and that the movement of other vortices at high-latitudes is also driven by interaction with the background vorticity.

Over the last few decades, spacecraft and ground-based observations have gathered data about Jupiter's atmosphere, including measurements of cloud reflectance (

The poles of Jupiter were observed in detail for the first time by the Juno spacecraft in 2016 (Bolton et al., 2017). In contrast with the polar regions of Saturn, which are inhabited by a single polar cyclone (PC) (Baines et al., 2009;Sánchez-Lavega et al., 2006), Jupiter's PCs are surrounded by a ring of stable circumpolar cyclones (CPCs) (Adriani et al., 2018;Orton et al., 2017). There are eight CPCs at the north pole and five at the south (Figure 1), each with a diameter of roughly 5,000 km and velocities reaching 100 ms −1 (Adriani et al., 2020;Grassi et al., 2018). Such cyclones can be generated by moist convection (O'Neill et al., 2015(O'Neill et al., , 2016, where 2D inverse energy cascade in the turbulent polar regions brings the kinetic energy from the convective scale up to the horizontal scale of the cyclones (Moriconi et al., 2020;. These regions are bounded by prograde jets at around latitudes 65°N∖S (Rogers et al., 2017(Rogers et al., , 2022, which may act as a separating barrier. In contrast with the Great Red Spot, which is centered around latitude 20°S and has a shallow depth (less than 500 km, Parisi et al. ( 2021)) relative to the deep surrounding jets (∼3,000 km, Kaspi et al. ( 2018)), the polar cyclones, subject to the Taylor-Proudman theorem (Vallis, 2017) with a vertical axis parallel to the planetary rotation axis and a smaller Rossby number, potentially extend deeper, suggesting a 2D dynamical regime.The beta-drift is a force that results from a dipole of vorticity (usually termed "beta-gyres," Sutyrin and Flierl (1994)) that is induced by an interaction between the tangential velocity of a cyclone and a gradient of potential vorticity (PV) that is present in the background of the cyclone (Chan, 2005;Gavriel & Kaspi, 2021;Rossby, 1948). This force creates a poleward drift on cyclones and an equatorward drift on anticyclones when only the planetary vorticity gradient (β) is considered (Chan, 2005;Franklin et al., 1996;Merlis & Held, 2019). Beta-drift is a known contributor to the poleward motion of Earth's tropical cyclones (Zhao et al., 2009), and was shown in shallow-water (SW) models to result in cyclones merging into a PC in settings characterizing gas-giants such as Jupiter and Saturn (

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<p>Jupiter’s atmosphere is governed by multiple jet streams, which are strongly tied to its three-dimensional atmospheric circulation. Lacking a solid surface, several theories exist for how the meridional circulation extends into the interior. Here we show, collecting evidence from multiple instruments of the Juno mission, the existence of mid-latitudinal, turbulent driven, meridional circulation cells, similar to the Ferrel cells on Earth. Different than Earth, which contains only one such cell in each hemisphere, Jupiter can incorporate multiple cells due to its large size and fast spin. The cells form regions of upwelling and downwelling, which we show are clearly evident in Juno’s MWR data between latitudes 60S and 60N. The existence of these cells is confirmed by reproducing the ammonia observations using an advection-relaxation model. This study solves a long-standing puzzle regarding the nature of Jupiter’s sub-cloud dynamics and provides evidence for 8 cells in each Jovian hemisphere.</p>