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Li C, de Pater I, Moeckel C, Sault RJ, Butler B, deBoer D, Zhang Z. Long-lasting, deep effect of Saturn's giant storms. SCIENCE ADVANCES 2023; 9:eadg9419. [PMID: 37566653 PMCID: PMC10421028 DOI: 10.1126/sciadv.adg9419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/12/2023] [Indexed: 08/13/2023]
Abstract
Planetary-scale giant storms erupt on Saturn quasiperiodically. There have been at least six recorded occurrences of past eruptions, and the most recent one was in 2010, with its whole life span captured by the Cassini mission. In 2015, we used the Very Large Array to probe the deep response of Saturn's troposphere to the giant storms. In addition to the remnant effect of the storm in 2010, we have found long-lasting signatures of all mid-latitude giant storms, a mixture of equatorial storms up to hundreds of years old, and potentially an unreported older storm at 70°N. We derive an ammonia anomaly map that shows an extended meridional migration of the storm's aftermath and vertical transport of ammonia vapor by storm dynamics. Intriguingly, the last storm in 2010 splits into two distinct components that propagate in opposite meridional directions, leaving a gap at 43°N planetographic latitude.
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Affiliation(s)
- Cheng Li
- Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Imke de Pater
- Department of Astronomy, University of California, Berkeley, Berkeley, CA, USA
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
| | - Chris Moeckel
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
| | - R. J. Sault
- School of Physics, University of Melbourne, Victoria 3010, Australia
| | - Bryan Butler
- National Radio Astronomy Observatory, Socorro, NM, USA
| | - David deBoer
- Department of Astronomy, University of California, Berkeley, Berkeley, CA, USA
| | - Zhimeng Zhang
- Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
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Creecy E, Li L, Jiang X, Smith M, Kass D, Kleinböhl A, Martínez G. Mars' emitted energy and seasonal energy imbalance. Proc Natl Acad Sci U S A 2022; 119:e2121084119. [PMID: 35576471 PMCID: PMC9173766 DOI: 10.1073/pnas.2121084119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/23/2022] [Indexed: 11/18/2022] Open
Abstract
SignificanceThe radiant energy budget is a fundamental metric for planets. Based on the observations from multiple missions, we provide a global picture of Mars' emitted power. Furthermore, we estimate the radiant energy budget of Mars, which suggests that there are energy imbalances at the time scale of Mars' seasons. Such energy imbalances provide a new perspective to understanding the generating mechanism of dust storms. Mars' radiant energy budget is assumed to be balanced at all time scales in current models and theories, but our analyses show that the energy budget is not balanced, at least at the time scale of Mars' seasons. Therefore, current theories and models should be revisited with the newly revealed energy characteristics.
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Affiliation(s)
- Ellen Creecy
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77004
| | - Liming Li
- Department of Physics, University of Houston, Houston, TX 77004
| | - Xun Jiang
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77004
| | - Michael Smith
- NASA Goddard Space Flight Center, Greenbelt, MD 20771
| | - David Kass
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
| | - Armin Kleinböhl
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
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Ingersoll AP. Cassini Exploration of the Planet Saturn: A Comprehensive Review. SPACE SCIENCE REVIEWS 2020; 216:122. [PMID: 35027776 PMCID: PMC8753610 DOI: 10.1007/s11214-020-00751-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 10/10/2020] [Indexed: 06/14/2023]
Abstract
Before Cassini, scientists viewed Saturn's unique features only from Earth and from three spacecraft flying by. During more than a decade orbiting the gas giant, Cassini studied the planet from its interior to the top of the atmosphere. It observed the changing seasons, provided up-close observations of Saturn's exotic storms and jet streams, and heard Saturn's lightning, which cannot be detected from Earth. During the Grand Finale orbits, it dove through the gap between the planet and its rings and gathered valuable data on Saturn's interior structure and rotation. Key discoveries and events include: watching the eruption of a planet-encircling storm, which is a 20- or 30-year event, detection of gravity perturbations from winds 9000 km below the tops of the clouds, demonstration that eddies are supplying energy to the zonal jets, which are remarkably steady over the 25-year interval since the Voyager encounters, re-discovery of the north polar hexagon after 25 years, determination of elemental abundance ratios He/H, C/H, N/H, P/H, and As/H, which are clues to planet formation and evolution, characterization of the semiannual oscillation of the equatorial stratosphere, documentation of the mysteriously high temperatures of the thermosphere outside the auroral zone, and seeing the strange intermittency of lightning, which typically ceases to exist on the planet between outbursts every 1-2 years. These results and results from the Jupiter flyby are all discussed in this review.
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Affiliation(s)
- Andrew P Ingersoll
- Division of Geological and Planetary Sciences, California Institute of Technology, 1200 East California Blvd, Pasadena, CA 91125, USA
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Trammell HJ, Li L, Jiang X, Pan Y, Smith MA, Bering EA, Hörst SM, Vasavada AR, Ingersoll AP, Janssen MA, West RA, Porco CC, Li C, Simon AA, Baines KH. Vortices in Saturn's Northern Hemisphere (2008-2015) Observed by Cassini ISS. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2016; 121:1814-1826. [PMID: 29629249 PMCID: PMC5886353 DOI: 10.1002/2016je005122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We use observations from the Imaging Science Subsystem on Cassini to create maps of Saturn's Northern Hemisphere (NH) from 2008 to 2015, a time period including a seasonal transition (i.e., Spring Equinox in 2009) and the 2010 giant storm. The processed maps are used to investigate vortices in the NH during the period of 2008-2015. All recorded vortices have diameters (east-west) smaller than 6000 km except for the largest vortex that developed from the 2010 giant storm. The largest vortex decreased its diameter from ~11000 km in 2011 to ~5000 km in 2015, and its average diameter is ~6500 km during the period of 2011-2015. The largest vortex lasts at least 4 years, which is much longer than the lifetimes of most vortices (less than 1 year). The largest vortex drifts to north, which can be explained by the beta drift effect. The number of vortices displays varying behaviors in the meridional direction, in which the 2010 giant storm significantly affects the generation and development of vortices in the middle latitudes (25-45°N). In the higher latitudes (45-90°N), the number of vortices also displays strong temporal variations. The solar flux and the internal heat do not directly contribute to the vortex activities, leaving the temporal variations of vortices in the higher latitudes (45-90°N) unexplained.
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Affiliation(s)
- Harold Justin Trammell
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas, USA
| | - Liming Li
- Department of Physics, University of Houston, Houston, Texas, USA
| | - Xun Jiang
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas, USA
| | - Yefeng Pan
- Department of Physics, University of Houston, Houston, Texas, USA
| | - Mark A Smith
- Department of Chemistry, University of Houston, Houston, Texas, USA
| | - Edgar A Bering
- Department of Physics, University of Houston, Houston, Texas, USA
| | - Sarah M Hörst
- Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Ashwin R Vasavada
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Andrew P Ingersoll
- Division of Geological and Planetary Sciences, Caltech, Pasadena, California, USA
| | - Michael A Janssen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Robert A West
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Carolyn C Porco
- Space Science and Engineering Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cheng Li
- Division of Geological and Planetary Sciences, Caltech, Pasadena, California, USA
| | - Amy A Simon
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - Kevin H Baines
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
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Li L. Dimming titan revealed by the Cassini observations. Sci Rep 2015; 5:8239. [PMID: 25649341 PMCID: PMC4316193 DOI: 10.1038/srep08239] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/12/2015] [Indexed: 11/10/2022] Open
Abstract
Here we report the temporal variation of Titan's emitted energy with the Cassini/CIRS observations. In the northern hemisphere, the hemispheric-average emitted power decreased from 2007 to 2009 and increased from 2009 to 2012-13, which make the net change insignificant (0.1 ± 0.2%) during the period 2007-2013. The decrease from 2007 to 2009 is mainly due to the cooling around the stratospause, and the increase from 2009 to 2012-13 is probably related to temporal variation of atmospheric temperature around the tropopuase in the northern hemisphere. In the southern hemisphere, the emitted power continuously decreased by 5.0 ± 0.6% from 2.40 ± 0.01 W/m(2) in 2007 to 2.28 ± 0.01 in 2012-13, which is mainly related to Titan's seasonal variation. The asymmetry in the temporal variation between the two hemispheres results in the global-average emitted power decreasing by 2.5 ± 0.6% from 2.41 ± 0.01 W/m(2) in 2007 to 2.35 ± 0.01 W/m(2) in 2012-13. The solar constant at Titan decreased by ~13.0% in the same period 2007-2013, which is much stronger than the temporal variation of emitted power. The measurements of Titan's absorbed solar power are needed to determine the temporal variation of the global energy budget.
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Affiliation(s)
- Liming Li
- Department of Physics, University of Houston, Houston, TX 77204, USA
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Li L, Achterberg RK, Conrath BJ, Gierasch PJ, Smith MA, Simon-Miller AA, Nixon CA, Orton GS, Flasar FM, Jiang X, Baines KH, Morales-Juberías R, Ingersoll AP, Vasavada AR, Del Genio AD, West RA, Ewald SP. Strong temporal variation over one Saturnian year: from Voyager to Cassini. Sci Rep 2013; 3:2410. [PMID: 23934437 PMCID: PMC3740281 DOI: 10.1038/srep02410] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 07/22/2013] [Indexed: 11/09/2022] Open
Abstract
Here we report the combined spacecraft observations of Saturn acquired over one Saturnian year (~29.5 Earth years), from the Voyager encounters (1980-81) to the new Cassini reconnaissance (2009-10). The combined observations reveal a strong temporal increase of tropic temperature (~10 Kelvins) around the tropopause of Saturn (i.e., 50 mbar), which is stronger than the seasonal variability (~a few Kelvins). We also provide the first estimate of the zonal winds at 750 mbar, which is close to the zonal winds at 2000 mbar. The quasi-consistency of zonal winds between these two levels provides observational support to a numerical suggestion inferring that the zonal winds at pressures greater than 500 mbar do not vary significantly with depth. Furthermore, the temporal variation of zonal winds decreases its magnitude with depth, implying that the relatively deep zonal winds are stable with time.
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Affiliation(s)
- Liming Li
- University of Houston, Houston, TX, USA.
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Sánchez-Lavega A, Río-Gaztelurrutia TD, Hueso R, Gómez-Forrellad JM, Sanz-Requena JF, Legarreta J, García-Melendo E, Colas F, Lecacheux J, Fletcher LN, Barrado-Navascués D, Parker D. Deep winds beneath Saturn’s upper clouds from a seasonal long-lived planetary-scale storm. Nature 2011; 475:71-4. [PMID: 21734704 DOI: 10.1038/nature10203] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Accepted: 05/10/2011] [Indexed: 11/09/2022]
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Fischer G, Kurth WS, Gurnett DA, Zarka P, Dyudina UA, Ingersoll AP, Ewald SP, Porco CC, Wesley A, Go C, Delcroix M. A giant thunderstorm on Saturn. Nature 2011; 475:75-7. [DOI: 10.1038/nature10205] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 05/17/2011] [Indexed: 11/09/2022]
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