Revisiting the Jupiter wind-induced gravity field: high harmonics and surface gravity

Since the first gravity measurements of Juno at Jupiter, the odd gravity harmonics J3 to J9 have been used to determine the depth of the zonal wind observed at the cloud level. Later on, combining solutions from internal models, the gravity harmonics J6, J8 and J10 were added to the analysis, which reinforced the conclusion that the observed zonal flows extend to a depth of around 3,000 km. The harmonics higher than J10 were not used in the analysis since their individual uncertainty was too large. In this study, we revisit the wind-gravity analysis, using new gravity data from Juno and a new analysis method, showing results for higher harmonic gravity measurements. This gives more detail about the structure of the deep zonal flows and allows better explaining the structure of the gravity spectrum. This confirms that indeed the observed flows are the ones which imprint the gravity spectrum. Moreover, this analysis allows to better determine which part of the wind field most contributes to the gravity signal, implying on the depth of individual jet streams. We also show how the new gravity measurement analysis allows to refine the surface gravity field, particularly in the latitudinal range of the closest approach of the spacecraft.