Journal of Geophysical Research: Planets最新文献

{"title":"Consus Crater on Ceres: Ammonium-Enriched Brines in Exchange With Phyllosilicates?","authors":"A. Nathues,&nbsp;M. Hoffmann,&nbsp;R. Sarkar,&nbsp;P. Singh,&nbsp;J. Hernandez,&nbsp;J. H. Pasckert,&nbsp;N. Schmedemann,&nbsp;G. Thangjam,&nbsp;E. Cloutis,&nbsp;K. Mengel,&nbsp;M. Coutelier","doi":"10.1029/2023JE008150","DOIUrl":"https://doi.org/10.1029/2023JE008150","url":null,"abstract":"<p>Ceres is a partially differentiated dwarf planet located in the main asteroid belt. Consus crater (diameter ∼64 km) is one of the oldest impact features (∼450 Ma) on the Cerean surface that surprisingly still shows a large variety of color lithologies, including exposures of bright material, which are thought to be brine residues. Here, we present new results that help in understanding the structure and composition of the Cerean crust. These results were deduced by using newly processed Dawn Framing Camera (FC) color imagery and FC clear filter images combined with infrared spectral data of Dawn's Visible and Infrared Spectrometer (VIR). Consus exhibits a variety of color lithologies, which we describe in detail. Interestingly, we found three spectrally different types of bright material exposed by a large old crater on Consus' floor. One of these, the yellowish bright material (Nathues et al., 2023, https://www.hou.usra.edu/meetings/lpsc2023/pdf/1073.pdf) and its modification, shows spectral signatures consistent with ammonium-enriched smectites. We hypothesize that the ammonium in these smectites stems from contact with ascending brines, originating from a low-lying former brine ocean that has been enriched in ammonium during the differentiation and freezing process of the Cerean crust. This enrichment is mainly due to ammonium uptake by sheet silicates. If such an ammonium enrichment occurred over long-time scales on a global scale, this process may explain the vast presence of ammonium on the Cerean surface. Therefore, an outer solar system origin of Ceres is possibly not needed to explain the global presence of ammonium.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008150","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shadowgraph Measurements of Rotating Convective Planetary Core-Style Flows","authors":"Jewel A. Abbate,&nbsp;Jonathan M. Aurnou","doi":"10.1029/2024JE008471","DOIUrl":"https://doi.org/10.1029/2024JE008471","url":null,"abstract":"<p>The local scale of rotating convection, <i>ℓ</i>, is a fundamental parameter in many turbulent geophysical and astrophysical fluid systems, yet it is often poorly constrained. Here we conduct rotating convection laboratory experiments analogous to convecting flows in planetary cores and subsurface oceans to obtain measurements of the local scales of motion. Utilizing silicone oil as the working fluid, we employ shadowgraph imagery to visualize the flow, from which we extract values of the characteristic cross-axial scale of convective columns and plumes. These measurements are compared to the theoretical values of the critical onset length scale, <i>ℓ</i>_<i>crit</i>, and the turbulent length scale, <i>ℓ</i>_<i>turb</i>. Our experimentally obtained length scale measurements simultaneously agree with both the onset and turbulent scale predictions across three orders of magnitude in convective supercriticality <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mrow>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>2</mn>\u0000 </msup>\u0000 <mo>≲</mo>\u0000 <mover>\u0000 <mrow>\u0000 <mi>R</mi>\u0000 <mi>a</mi>\u0000 </mrow>\u0000 <mo>∼</mo>\u0000 </mover>\u0000 <mo>≲</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>5</mn>\u0000 </msup>\u0000 </mrow>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation> $(1{0}^{2}lesssim tilde{Ra}lesssim 1{0}^{5})$</annotation>\u0000 </semantics></math>, a correlation that is consistent with inferences made in prior studies. We further explore the nature of this correlation and its implications for geophysical and astrophysical systems.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008471","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142137858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationships Between HCl, H2O, Aerosols, and Temperature in the Martian Atmosphere: 1. Climatological Outlook","authors":"K. S. Olsen,&nbsp;A. A. Fedorova,&nbsp;D. M. Kass,&nbsp;A. Kleinböhl,&nbsp;A. Trokhimovskiy,&nbsp;O. I. Korablev,&nbsp;F. Montmessin,&nbsp;F. Lefèvre,&nbsp;L. Baggio,&nbsp;J. Alday,&nbsp;D. A. Belyaev,&nbsp;J. A. Holmes,&nbsp;J. P. Mason,&nbsp;P. M. Streeter,&nbsp;K. Rajendran,&nbsp;M. R. Patel,&nbsp;A. Patrakeev,&nbsp;A. Shakun","doi":"10.1029/2024JE008350","DOIUrl":"https://doi.org/10.1029/2024JE008350","url":null,"abstract":"<p>Detecting trace gases such as hydrogen chloride (HCl) in Mars' atmosphere is among the primary objectives of the ExoMars Trace Gas Orbiter (TGO) mission. Terrestrially, HCl is closely associated with active volcanic activity, so its detection on Mars was expected to point to some form of active magmatism/outgassing. However, after its discovery using the mid-infrared channel of the TGO Atmospheric Chemistry Suite (ACS MIR), a clear seasonality was observed, beginning with a sudden increase in HCl abundance from below detection limits to 1–3 ppbv in both hemispheres coincident with the start of dust activity, followed by very sudden and rapid loss at the southern autumnal equinox. In this study, we have investigated the relationship between HCl and atmospheric dust by making comparisons in the vertical distribution of gases measured with ACS and aerosols measured co-located with the Mars Climate Sounder (MCS). This study includes HCl, water vapor, and ozone measured using ACS MIR, water vapor and temperature measured with the near infrared channel of ACS, and temperature, dust opacity, and water ice opacity measured with MCS. In part 1, we show that dust loading has a strong impact in temperature, which controls the abundance of water ice and water vapor, and that HCl is very closely linked to water activity. In part 2, we investigate the quantitative correlations between each quantity and discuss the possible source and sinks of HCl, their likelihood given the correlations, and any issues arising from them.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008350","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142077815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationships Between HCl, H2O, Aerosols, and Temperature in the Martian Atmosphere: 2. Quantitative Correlations","authors":"K. S. Olsen,&nbsp;A. A. Fedorova,&nbsp;D. M. Kass,&nbsp;A. Kleinböhl,&nbsp;A. Trokhimovskiy,&nbsp;O. I. Korablev,&nbsp;F. Montmessin,&nbsp;F. Lefèvre,&nbsp;L. Baggio,&nbsp;J. Alday,&nbsp;D. A. Belyaev,&nbsp;J. A. Holmes,&nbsp;J. P. Mason,&nbsp;P. M. Streeter,&nbsp;K. Rajendran,&nbsp;M. R. Patel,&nbsp;A. Patrakeev,&nbsp;A. Shakun","doi":"10.1029/2024JE008351","DOIUrl":"https://doi.org/10.1029/2024JE008351","url":null,"abstract":"<p>The detection of hydrogen chloride (HCl) in the atmosphere of Mars was among the primary objectives of the ExoMars Trace Gas Orbiter (TGO) mission. Its discovery using the Atmospheric Chemistry Suite mid-infrared channel (ACS MIR) showed a distinct seasonality and possible link to dust activity. This paper is part 2 of a study investigating the link between HCl and aerosols by comparing gas measurements made with TGO to dust and water ice opacities measured with the Mars Climate Sounder (MCS). In part 1, we showed, and compared, the seasonal evolution of vertical profiles of HCl, water vapor, temperature, dust opacity, and water ice opacity over the dusty periods around perihelion (solar longitudes 180°–360°) across Mars years 34–36. In part 2, we investigated the quantitative correlations in the vertical distribution between each quantity, as well as ozone. We show that there is a strong positive correlation between HCl and water vapor, which is expected due to fast photochemical production rates for HCl when reacting with water vapor photolysis products. We also show a strong positive correlation between water vapor and temperature, but are unable to show any correlation between temperature and HCl. There are weak correlations between the opacities of dust and water ice, and dust and water vapor, but only very low correlations between dust and HCl. We close with a discussion of possible sources and sinks and that interactions between HCl and water ice are the most likely for both, given the inter-comparison.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JE008351","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142077920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated Spectral and Compositional Analysis for the Lunar Tsiolkovskiy Crater","authors":"Gloria Tognon,&nbsp;Francesca Zambon,&nbsp;Cristian Carli,&nbsp;Matteo Massironi,&nbsp;Lorenza Giacomini,&nbsp;Riccardo Pozzobon,&nbsp;Giulia Salari,&nbsp;Federico Tosi,&nbsp;Jean-Philippe Combe,&nbsp;Sergio Fonte","doi":"10.1029/2023JE008272","DOIUrl":"https://doi.org/10.1029/2023JE008272","url":null,"abstract":"<p>Remote sensing observations represent the primary means in the production of geologic maps of planetary surfaces. However, they do not provide the same level of detail as Earth's geologic maps, which rely also on field observations and laboratory analyses. Color-derived basemaps can help to bridge this gap by highlighting peculiar surface and compositional properties. Here, we analyzed the spectral properties of the lunar Tsiolkovskiy crater through the definition of spectral units summarizing the information enclosed by a set of selected spectral parameters. We then performed a compositional analysis of the newly derived spectral units that helped us in discriminating the presence and relative abundance of the main mineralogical phases on the Moon. As a final step, we produced a geo-stratigraphic map of the Tsiolkovskiy crater integrating in a single mapping product both morphologic, stratigraphic and compositional information. The basaltic infilling of the crater is distinguished by three spectral units associated with distinct effusive events presenting a different composition. On the central peak, plagioclase and olivine suggest the presence of Mg-suite rocks from the lower crust. The continuous ejecta deposits are mostly characterized by impact melts and shocked materials rich in glass or agglutinates related to more mature terrains from which occasionally appear fresher anorthositic and gabbroic outcrops exposed by the inward sliding of the crater walls. Overall, the geo-stratigraphic map allows inferring compositional variations associated with the different morpho-stratigraphic units, which clarify and elaborate on the compositional heterogeneities within the lunar crust and the Tsiolkovskiy crater, and its geologic evolutionary history.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008272","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142045287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Statistical Study of the Vertical Scale Height of the Martian Ionosphere Using MAVEN Observations","authors":"Wendong Liu,&nbsp;Libo Liu,&nbsp;Yiding Chen,&nbsp;Huijun Le,&nbsp;Yuyan Yang,&nbsp;Wenbo Li,&nbsp;Han Ma,&nbsp;Hui Zhang","doi":"10.1029/2024JE008450","DOIUrl":"https://doi.org/10.1029/2024JE008450","url":null,"abstract":"<p>The Vertical Scale Height (VSH) is a crucial parameter that describes the shape of the ionospheric electron density profile. Evidence suggests a complex relationship between VSH and the thermal structure and dynamics of the ionosphere. A statistical study was conducted on the VSH at low altitudes (175 km) and high altitudes (300 km) in the Martian ionosphere, using data from the MAVEN observations from 2014 to 2023. The results suggest that the influence of the crustal magnetic field on VSH₁₇₅ is more pronounced than on VSH₃₀₀. VSH₁₇₅ shows a minor peak around −20° latitudes, which is more than 7% higher than the average value, and an increasing trend with latitude in the northern hemisphere. VSH₃₀₀ is higher in the southern hemisphere than in the northern hemisphere, especially in summer, by approximately 42.1%. Regarding the local time variation of VSH, we observed an increasing trend from midnight to morning and a decreasing trend from dusk to midnight in almost all conditions. The local time variation of VSH also exhibits seasonal and latitudinal dependence. These variations have different levels of consistency with the gradient of the electron temperature (Te) and the collision frequency between charged particles and neutrals. Specifically, the correlation coefficient between VSH₁₇₅ and the collision frequency between charged particles and neutrals reaches as high as 0.93 in the northern hemisphere winter and southern hemisphere summer. The correlation coefficient between VSH₃₀₀ and the gradient of the Te reaches up to 0.72 in the southern hemisphere equinox.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large Glacier-Like Forms on Mars: Insights From Crater Morphologies and Crater Retention Ages","authors":"G. Driver,&nbsp;M. R. El-Maarry,&nbsp;B. Hubbard,&nbsp;S. Brough","doi":"10.1029/2023JE008207","DOIUrl":"https://doi.org/10.1029/2023JE008207","url":null,"abstract":"<p>Glacier-Like Forms (GLFs) are a subset of ice-rich landforms known as Viscous Flow Features that populate Mars' mid-latitudes. GLFs are morphologically similar to terrestrial valley glaciers and are thought to result from the redistribution of water ice from the Martian poles during periods of high obliquity throughout the Amazonian period. Their ages, formation, and evolutionary processes are poorly constrained. We selected the 100 largest GLFs from the most recent GLF population data set, and by analyzing their superimposing crater morphologies and populations, we calculated their Crater Retention Ages (CRAs) and identified any relationships between CRAs, crater morphologies, and GLF geometries. We also organized the crater morphologies into states of degradation based on the understood erosional sequences. 3,630 craters were mapped, which we classified into 15 different crater morphologies. We calculated 98 CRAs, ranging from ∼2.88 Ma to ∼3.5 Ga. On average, GLFs in the southern hemisphere have younger CRAs, higher average slopes, smaller crater populations, and show less variability in crater morphological development than in the northern hemisphere. GLFs with higher mean slopes display less crater morphology variety, suggesting that shallow GLFs experience less reworking than steeper GLFs. We propose that these regional and hemispheric differences are due to a combination of favorable topography and climate conditions, both during and between high obliquity periods. We present several scenarios for the GLFs observed in this study and suggest that the glacial and erosional processes that affect GLF evolution are likely locale-dependent.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE008207","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142021788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probable Concretions Observed in the Shenandoah Formation of Jezero Crater, Mars and Comparison With Terrestrial Analogs","authors":"H. Kalucha,&nbsp;A. Broz,&nbsp;N. Randazzo,&nbsp;J. Aramendia,&nbsp;J. M. Madariaga,&nbsp;B. Garczynski,&nbsp;N. Lanza,&nbsp;L. Mandon,&nbsp;T. Fouchet,&nbsp;D. C. Catling,&nbsp;A. G. Fairén,&nbsp;L. Kivrak,&nbsp;P. J. Gasda,&nbsp;J. I. Núñez,&nbsp;E. Cloutis,&nbsp;K. P. Hand,&nbsp;J. W. Rice Jr.,&nbsp;W. W. Fischer,&nbsp;S. Maurice,&nbsp;R. C. Wiens","doi":"10.1029/2023JE008138","DOIUrl":"https://doi.org/10.1029/2023JE008138","url":null,"abstract":"<p>The Mars 2020 <i>Perseverance</i> Rover imaged diagenetic textural features in four separate sedimentary units in its exploration of the 25-m-thick Shenandoah formation at Jezero Crater, Mars, that we interpreted as probable concretions. These concretions were most abundant in the Hogwallow Flats member of the Shenandoah formation and were restricted to the light-toned, platy, sulfur-cemented bedrock at outcrop surfaces, whereas the finely laminated, darker toned, mottled and deformed strata lack concretions. The concretions also had a wide range of morphologies including concentric, oblate, urn, and spheroidal shaped forms that were not clustered, and ranged in size from ∼1 to 16 mm with a median of 2.65 mm. The elemental composition of the concretions compared to the bedrock had greater abundance of magnesium and calcium salts, silicates, and possibly hematite. We compared these Jezero Crater concretions to the geochemistry of concretions from previously published studies and from two new terrestrial analog sites (Gallup Formation, New Mexico and Torrey Pines, California). In addition, we measured organic carbon content of three terrestrial sedimentary analogs of increasing age that contain concretions (Torrey Pines (Pleistocene), Gallup Formation (∼89 Ma), and Moodies Group (∼3.2 Ga)). All measured concretions contained significant concentrations of organic carbon with the maximum organic carbon content (∼2 wt. % Total organic carbon) found in the Moodies Group concretions. Organic carbon abundances in terrestrial concretions was controlled more by the formation mechanism and relative timing of concretion development rather than deposit age. These findings suggested that concretions at Jezero Crater reflect local sites of enhanced biosignature preservation potential.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142007210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights Into Lunar Basaltic Volcanism From Mare Domes Superposed by Ring-Moat Dome Structures (RMDSs) in Mare Tranquillitatis","authors":"Feng Zhang,&nbsp;James W. Head,&nbsp;Lionel Wilson,&nbsp;Yibo Meng,&nbsp;Christian Wӧhler,&nbsp;Dijun Guo,&nbsp;Shengli Niu,&nbsp;Roberto Bugiolacchi,&nbsp;Le Qiao,&nbsp;Yanan Dang,&nbsp;Yang Liu,&nbsp;Yongliao Zou","doi":"10.1029/2023JE007969","DOIUrl":"https://doi.org/10.1029/2023JE007969","url":null,"abstract":"<p>Mare domes (interpreted to be a type of shield volcano) represent one important endmember of a variety of volcanic edifices occurring across the volcanic plains on the Moon, whereas Ring-Moat Dome Structures (RMDSs) are interpreted to reflect the thermodynamic behavior of plain-forming mare flows during their emplacement and cooling. A comprehensive study of the direct association between mare domes and RMDSs can not only provide deep insights into their formation mechanisms but also yield key information on the nature of mantle sources. We characterized a total of 200 mare domes and more than 6,400 RMDSs within Mare Tranquillitatis using multiple sets of imagery and topography data. RMDS-bearing domes (80 out of 200) are on average larger than those hosting no RMDSs (average diameter 10.2 vs. 5.5 km) and have lower height/diameter (H/D) ratios (0.01 vs. 0.02) and flank slopes (1.2° vs. 2°). We attribute the presence of RMDSs on some domes to be due to relatively higher effusion rates forming longer thinner flows, producing favorable conditions for the formation of RMDSs. The average diameter of the RMDSs on mare domes (226 m, <i>n</i> = 1,027) appears to be slightly smaller than those located in mare plains (256 m, <i>n</i> = 527). This may be due to slope effects and that the relatively thicker off-dome part of flows undergoes a relatively higher degree inflation process, producing slightly larger RMDSs. We adapt the RMDS-formation theoretical model to shallow subcrustal magma reservoir model to account for the Tranquillitatis dome-RMDS associations.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JE007969","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141994149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Simulations of Magnetic Effects on Zonal Flows in Giant Planets","authors":"Shanshan Xue,&nbsp;Yufeng Lin","doi":"10.1029/2023JE008280","DOIUrl":"https://doi.org/10.1029/2023JE008280","url":null,"abstract":"<p>Jupiter and Saturn exhibit alternating east-west jet streams. The origin of these zonal flows has been debated for decades. The high-precision gravity measurements by the Juno mission and the grand finale of the Cassini mission have revealed that the observed zonal flows may extend several thousand kilometres deep and stop around the transition region from molecular to metallic hydrogen, suggesting the magnetic braking effect on zonal flows. In this study, we perform a set of magnetohydrodynamic simulations in a spherical shell with radially variable electrical conductivity to investigate the interaction between magnetic fields and zonal flows. A key feature of our numerical models is that we impose a background dipole magnetic field on the anelastic rotating convection. By varying the strength of the imposed magnetic field and the vigor of convection, we investigate how the magnetic field interacts with the convective motions and the convection-driven zonal flows. Our simulations reveal that the magnetic field tends to destroy zonal flows in the metallic hydrogen and suppress zonal flows in the molecular envelope, while the magnetic field may enhance the radial convective motions. We extract a quantitative relation between the magnetic field strength and the amplitude of zonal flows at the surface through our simulations, which roughly matches the observed magnetic field and zonal wind speed of Jupiter and Saturn. This discovery provides support from a new perspective for the scenario of deep convection-driven zonal winds which are confined to the molecular hydrogen layers in giant planets.</p>","PeriodicalId":16101,"journal":{"name":"Journal of Geophysical Research: Planets","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141980304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}