Linking zonal winds and gravity – II. Explaining the equatorially antisymmetric gravity moments of Jupiter

ABSTRACT The recent gravity field measurements of Jupiter (Juno) and Saturn (Cassini) confirm the existence deep zonal flows reaching to a depth 5 per cent 15 respective radius. Relating wind-induced density perturbations moments has become major tool characterize interior dynamics gas giants. Previous studies differ with respect assumptions made on how wind velocity relates anomalies, functional form its decay depth, continuity antisymmetric winds across equatorial plane. For case Jupiter, most suggested vertical structures exhibit rather smooth radial wind, which seems at odds observed secular variation magnetic prevailing barotropy winds. Moreover, results relied modifications surface flows, an artificial regularization or ignored discontinuity altogether. We favour alternative structure, where equatorially in latitude belt between ±21° remains so shallow that it does not contribute signal. higher latitudes suffice convincingly explain measured moments. Our indicate are barotropic, i.e. constant along cylinders, outer $3000$ km rapidly below. preferred structure is 50 deeper than previously thought, agrees odd moments, compliant requirement adiabatic atmosphere unbiased by treatment discontinuity. discuss possible implications for interpretation Jupiter’s field.