Implications of the ammonia distribution on Jupiter from 1 to 100 bars as measured by the Juno microwave radiometer

Ingersoll, Andrew P.; Adumitroaie, Virgil; Allison, M.; Atreya, S. K.; Bellotti, Amadeo; Bolton, S. J.; Brown, Shannon; Gulkis, S.; Janssen, M. A.; Levin, S. M.; Li, Cheng; Li, Liming; Lunine, Jonathan I.; Orton, Glenn S.; Oyafuso, Fabiano; Steffes, Paul G.

doi:10.1002/2017gl074277

Cited by 45 publications

(84 citation statements)

References 65 publications

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“…Let us follow the upward motion of a water droplet formed below the 5-bar level in Jupiter's deep atmosphere by following the red ribbon in Figure 1 from right to left. As liquid, it can dissolve a small fraction of ammonia-but this fraction remains smaller than a percent in equilibrium conditions and reaches a few percent only by invoking large supercooling of the water droplets to −20°C or so, as obtained by Ingersoll et al (2017). When the droplet freezes to become an ice crystal, the equilibrium solution predicts the existence of pure water ice, implying that any ammonia must be expelled.…”

Section: The Nh 3 -H 2 O Phase Diagrammentioning

confidence: 96%

Storms and the Depletion of Ammonia in Jupiter: I. Microphysics of “Mushballs”

et al. 2020

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Microwave observations by the Juno spacecraft have shown that, contrary to expectations, the concentration of ammonia is still variable down to pressures of tens of bars in Jupiter. We show that during strong storms able to loft water ice into a region located at pressures between 1.1 and 1.5 bar and temperatures between 173 and 188 K, ammonia vapor can dissolve into water ice to form a low‐temperature liquid phase containing about one‐third ammonia and two‐third water. We estimate that, following the process creating hailstorms on Earth, this liquid phase enhances the growth of hail‐like particles that we call mushballs. We develop a simple model to estimate the growth of these mushballs, their fall into Jupiter's deep atmosphere, and their evaporation. We show that they evaporate deeper than the expected water cloud base level, between 5 and 27 bar depending on the assumed abundance of water ice lofted by thunderstorms and on the assumed ventilation coefficient governing heat transport between the atmosphere and the mushball. Because the ammonia is located mostly in the core of the mushballs, it tends to be delivered deeper than water, increasing the efficiency of the process. Further sinking of the condensates is expected due to cold temperature and ammonia‐ and water‐rich downdrafts formed by the evaporation of mushballs. This process can thus potentially account for the measurements of ammonia depletion in Jupiter's deep atmosphere.

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Section: The Nh 3 -H 2 O Phase Diagrammentioning

confidence: 96%

Storms and the Depletion of Ammonia in Jupiter: I. Microphysics of “Mushballs”

et al. 2020

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“…There is excellent overlap in sounding Jupiter between 5 µm and 3 of the 6 MWR channels, namely at 3.125 cm, 6.25 cm, and 12.5 cm. Early Juno results on measurements of NH 3 in the deep atmosphere using MWR were presented by Li et al (2017b) and Ingersoll et al (2017). In July, 2017 Juno's orbit passed over the Great Red Spot yielding both spectacular images and microwave observations, which are currently being analyzed (Li et al 2017a).…”

Section: Introductionmentioning

confidence: 99%

The Gas Composition and Deep Cloud Structure of Jupiter's Great Red Spot

Bjoraker¹,

Wong

Pater

et al. 2018

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We have obtained high-resolution spectra of Jupiter's Great Red Spot (GRS) between 4.6 and 5.4 µm using telescopes on Mauna Kea in order to derive gas abundances and to constrain its cloud structure between 0.5 and 5 bars. We used line profiles of deuterated methane (CH 3 D) at 4.66 µm to infer the presence of an opaque cloud at 5±1 bars. From thermochemical models this is almost certainly a water cloud. We also used the strength of Fraunhofer lines in the GRS to obtain the ratio of reflected sunlight to thermal emission. The level of the reflecting layer was constrained to be at 570±30 mbars based on fitting strong NH 3 lines at 5.32 µm. We identify this layer as an ammonia cloud based on the temperature where gaseous NH 3 condenses. We found evidence for a strongly absorbing, but not totally opaque, cloud layer at pressures deeper than 1.3 bars by combining Cassini/CIRS spectra of the GRS at 7.18 µm with ground-based spectra at 5 µm. This is consistent with the predicted level of an NH 4 SH cloud. We also constrained the vertical profile of H 2 O and NH 3 . The GRS spectrum is matched by a saturated H 2 O profile above an opaque water cloud at 5 bars. The pressure of the water cloud constrains Jupiter's O/H ratio to be at least 1.1 times solar. The NH 3 mole fraction is 200±50 ppm for pressures between 0.7 and 5 bars. Its abundance is 40 ppm at the estimated pressure of the reflecting layer. We obtained 0.8±0.2 ppm for PH 3 , a factor of 2 higher than in the warm collar surrounding the GRS. We detected all 5 naturally occurring isotopes of germanium in GeH 4 in the Great Red Spot. We obtained an average value of 0.35±0.05 ppb for GeH 4 . Finally, we measured 0.8±0.2 ppb for CO in the deep atmosphere.

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“…The observed ammonia upwelling near the equator, with an ammonia‐poor layer near 6 bars extending to midlatitudes, poses a number of questions about the kinematics of Jupiter's atmosphere. Some of these mysteries could be explained by a structure like the Earth's Hadley cell, but it is clear that our first radiometric measurement of Jupiter's deep atmosphere poses more questions than it answers [ Ingersoll et al, ]. These are just the first steps of a new way to study the solar system's largest planet.…”

Section: Atmospherementioning

confidence: 97%

“…of these mysteries could be explained by a structure like the Earth's Hadley cell, but it is clear that our first radiometric measurement of Jupiter's deep atmosphere poses more questions than it answers [Ingersoll et al, 2017]. These are just the first steps of a new way to study the solar system's largest planet.…”

Section: Introduction To a Special Sectionmentioning

confidence: 99%

Juno's first glimpse of Jupiter's complexity

Bolton

Levin

Bagenal

2017

Geophysical Research Letters

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Preliminary results from NASA's Juno mission are presented in this special issue of Geophysical Research Letters. The data were gathered by nine scientific instruments as the Juno spacecraft approached Jupiter on the dawn flank, was inserted into Jupiter orbit on 4 July 2016, and made the first polar passes close to the planet. The first results hint that Jupiter may not have a distinct core, indicate puzzling deep atmospheric convection, and reveal complex small‐scale structure in the magnetic field and auroral processes that are distinctly different from those at Earth.

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Implications of the ammonia distribution on Jupiter from 1 to 100 bars as measured by the Juno microwave radiometer

Cited by 45 publications

References 65 publications

Storms and the Depletion of Ammonia in Jupiter: I. Microphysics of “Mushballs”

Storms and the Depletion of Ammonia in Jupiter: I. Microphysics of “Mushballs”

The Gas Composition and Deep Cloud Structure of Jupiter's Great Red Spot

Juno's first glimpse of Jupiter's complexity

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