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Equilibrium Temperatures and Directional Emissivity of Sunlit Airless Surfaces With Applications to the Moon
-  9 June 2020
Key Points
- We derive equations to calculate the equilibrium temperature distribution of illuminated rough Gaussian surfaces
- Using our model, we estimate the surface roughness of the Moon at ∼1 cm lateral scales
- Our model may be used to measure small‐scale surface roughness on airless planetary bodies, such as small moons and asteroids
Temperature Variability in Titan's Upper Atmosphere: The Role of Wave Dissipation
-  28 May 2020
Key Points
- We construct a linearized wave model to evaluate the role of wave heating and cooling in Titan's upper atmosphere
- Wave heating by molecular diffusion is an important mechanism that influences the thermal structure of Titan's upper atmosphere
- The predicted temperature variability is likely greater than that caused by particle precipitation but still smaller than that observed
Temperature‐Dependent Changes in the Normal Albedo of the Lunar Surface at 1,064 nm
-  18 May 2020
Key Points
- The Lunar Orbiter Laser Altimeter is sensitive to temperature‐dependent changes of normal albedo
- At 1,064 nm, the maria show a slightly stronger negative change in surface reflectance with temperature than the highlands
- The measured temperature‐dependent changes in normal albedo are consistent with the presence of pyroxene at the lunar surface
Spectral Properties and Physical Extent of Pyroclastic Deposits on Mercury: Variability Within Selected Deposits and Implications for Explosive Volcanism
-  30 April 2020
Key Points
- Variations in spectral properties are correlated with the distance from the source
- Grain size, regolith mixing, and/or the presence of an opaque/mineral are possible controlling factors in the spectral variability observed
- Faculae (e.g., Bitin, Agwo, Orm) have a larger spatial extent than image data alone suggest
Open accessAzimuthal Anisotropy of the Megaregolith at the Apollo 14 Landing Site
-  30 April 2020
Key Points
- We apply seismic interferometry to S ‐wave coda of deep moonquakes
- Weak azimuthal anisotropy is found between 0‐ and 1‐km depth at the Apollo 14 site
- We interpret a layer (or layers) of impact material, following the Imbrium impact, with internal alignment of the crushed material
Asymmetries in Snowfall, Emissivity, and Albedo of Mars' Seasonal Polar Caps: Mars Climate Sounder Observations
- C. E. Gary‐Bicas
- P. O. Hayne
- T. Horvath
- N. G. Heavens
- D. M. Kass
- A. Kleinböhl
- S. Piqueux
- J. H. Shirley
- J. T. Schofield
- D. J. McCleese
-  30 April 2020
Key Points
- Infrared emissivity and visible albedo of Mars' seasonal ice caps are correlated
- The north seasonal cap has greater snowfall, lower emissivity, and lower albedo
- Higher dust loading in the northern fall and winter seasons causes lower ice cap albedo
Contributions to Jupiter's Gravity Field From Dynamics in the Dynamo Region
-  30 April 2020
Key Points
- We estimate the zonal gravity harmonics produced by zonal flow in Jupiter's dynamo region
- Zonal flow in the dynamo region with a RMS velocity of 10 cm s-1 would produce large J2 , J3 , and J4 values
- Zonal flows above the dynamo region are responsible for producing dynamical gravity harmonics above J4
Geochemistry and Petrogenesis of Northwest Africa 10401: A New Type of the Mg‐Suite Rocks
-  30 April 2020
Key Points
- NWA 10401 records the highest known bulk Mg# of feldspathic lunar meteorites, with a value of 82
- NWA 10401 seems consistent with being derived from a common parent to the troctolites from the Apollo Mg‐suite but is KREEP poor based on major and trace element of mineral grains and bulk compositions
- NWA 10401 could represent a KREEP‐poor Mg‐suite component outside the PKT indicating that Mg‐suite magmatism was not driven by KREEP and may have been a global occurrence
Constraints on the Abundances of Carbon and Silicon in Mercury's Core From Experiments in the Fe‐Si‐C System
-  30 April 2020
Key Points
- Composition is the main control of carbon concentration at graphite saturation in Fe‐rich metal, with minimal effects from temperature and pressure
- Mercury requires ≥27 wt% Si and ≤0.5 wt% C in its core if it has a bulk EH chondritic composition
- Mercury requires 5–18.5 wt% Si and 0.8–4.0 wt% C in its core if it has a bulk CB chondritic composition
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Ganymede, then and now: How past eccentricity may have altered tidally driven Coulomb failure
- Marissa E. Cameron
- Bridget R. Smith‐Konter
- Geoffrey C. Collins
- Donald A. Patthoff
- Robert T. Pappalardo
-  28 May 2020
Two‐year observations of the Jupiter polar regions by JIRAM on board Juno
- A. Adriani
- A. Bracco
- D. Grassi
- M. L. Moriconi
- A. Mura
- G. Orton
- F. Altieri
- A. Ingersoll
- S. K. Atreya
- J. I. Lunine
- A. Migliorini
- R. Noschese
- A. Cicchetti
- R. Sordini
- F. Tosi
- G. Sindoni
- C. Plainaki
- B. M. Dinelli
- D. Turrini
- G. Filacchione
- G. Piccioni
- S. J. Bolton
-  28 May 2020
Key Points
- The Jupiter's polar cyclonic structures did not change much in two years of observations from February 2017 to February 2019.
- Abundances of some atmospheric minor constituents measured in the hottest spots of the polar regions, higher values registered in the south.
- Earth oceanic cyclones analogies suggest a well‐mixed upper boundary layer on Jupiter's Poles.
Grain Size Dependence of Brightness Phase Curves of the Lunar Surface
-  28 May 2020
Key Points:
- The opposition effect is known to be mainly from shadow hiding effect and coherent backscattering.
- However, the contribution of coherent backscattering are not well‐known yet.
- We find that the coherent backscattering between discrete particles seems to have a weak influence on the lunar surface even when the phase angle is small enough.
Spatial and temporal variability of the 365‐nm albedo of Venus observed by the camera on board Venus Express
-  28 May 2020
keypoints
- Temporal variations of the 365~nm albedo of Venus dominate over any systematic variations along longitude or over local time
- We found no systematic influence by mountains on the 365~nm albedo distribution, in contrast to a previous report
Chlorine Release from Common Chlorides by Martian Dust Activity
-  28 May 2020
Key Points:
- Instantaneous emission of the plasma line of 1st excited state of Cl atom during electrostatic discharge (ESD) on three chlorides in a Mars chamber.
- Deposition of Cl‐bearing film (mainly CuCl) occurs on the upper electrode after 7 hours of ESD on each of seven chlorides.
- Above observations suggest that electrochemistry induced by dust activity on present day of Mars can drive Cl cycling between the surface and atmosphere.
Constraints on the Mineralogy and Geochemistry of the Vera Rubin ridge, Gale crater, Mars, from Mars Science Laboratory Sample Analysis at Mars Evolved Gas Analyses
- Amy C. McAdam
- Brad Sutter
- P. Douglas Archer
- Heather B. Franz
- Gregory M. Wong
- James M. T. Lewis
- Jennifer L. Eigenbrode
- Jennifer C. Stern
- Christine A. Knudson
- Joanna V. Clark
- Slavka Andrejkovičová
- Douglas W. Ming
- Richard V. Morris
- Cherie N. Achilles
- Elizabeth B. Rampe
- Thomas F. Bristow
- Rafael Navarro‐González
- Paul R. Mahaffy
- Lucy M. Thompson
- Ralf Gellert
- Amy J. Williams
- Christopher H. House
- Sarah S. Johnson
-  28 May 2020
Key Points:
- Vera Rubin ridge expezcted, including sulfate, chloride, nitrate and oxychlorine salts, enabling constraints on diagenetic fluid chemistry.
Lunar Irregular Mare Patches (IMPs): Classification, Characteristics, Geologic Settings, Updated Catalog, Origin and Outstanding Questions
-  28 May 2020
Key Points:
- We present an updated catalog of 91 lunar Irregular Mare Patches (IMPs) and survey the geologic settings and characteristics of each IMP
- Two classification schemes for the entire IMP population are proposed on the basis of their geologic settings and characteristics
- The characteristics of lunar IMPs are consistent with the waning‐stage magmatic foam extrusion origin model in different environments
Martian Infrasound: Numerical Modeling and Analysis of InSight's Data
-  28 May 2020
Key Points
- Our numerical modeling predicts both pressure variations and ground movements induced by Martian acoustic waves.
- Regional propagation of dispersed infrasound is expected in the Martian nocturnal surface waveguide.
- Some monotone events detected by SEIS are consistent with acoustic waves trapped in this waveguide.
Compositional Measurements of Saturn's Upper Atmosphere and Rings from Cassini INMS
-  28 May 2020
Key Points
- We measure the density profiles of H$_2$, He, CH$_4$, H$_2$O, and NH$_3$ in Saturn's upper atmosphere from Cassini INMS.
- We use a new mass spectral deconvolution algorithm to determine the relative abundances of different species found in the mass spectra.
- We report further evidence of CH$_4$, H$_2$O, and NH$_3$ entering Saturn's atmosphere from the rings at a rate of at least 10$^3$ kg/s.
Pressure effects on the SEIS‐InSight instrument, improvement of seismic records and characterization of long period atmospheric waves from ground displacements
- Raphael F. Garcia
- Balthasar Kenda
- Taichi Kawamura
- A. Spiga
- N. Murdoch
- P. Lognonné
- R. Widmer‐Schnidrig
- N. Compaire
- G. Orhand‐Mainsant
- D. Banfield
- W. B. Banerdt
-  26 May 2020
Key Points
- Coherence between pressure and seismic measurements is high in the 0.05‐0.3 Hz range during active day time periods
- Atmospheric noise can be removed efficiently from seismic records in the frequency ranges where coherence is high
- Arrival azimuth of night time atmospheric gravity waves is estimated from SEIS data
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Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE)
- Alfred S. McEwen
- Eric M. Eliason
- James W. Bergstrom
- Nathan T. Bridges
- Candice J. Hansen
- W. Alan Delamere
- John A. Grant
- Virginia C. Gulick
- Kenneth E. Herkenhoff
- Laszlo Keszthelyi
- Randolph L. Kirk
- Michael T. Mellon
- Steven W. Squyres
- Nicolas Thomas
- Catherine M. Weitz
- Journal of Geophysical Research: Planets
-  17 May 2007
free accessMars Orbiter Laser Altimeter: Experiment summary after the first year of global mapping of Mars
- David E. Smith
- Maria T. Zuber
- Herbert V. Frey
- James B. Garvin
- James W. Head
- Duane O. Muhleman
- Gordon H. Pettengill
- Roger J. Phillips
- Sean C. Solomon
- H. Jay Zwally
- W. Bruce Banerdt
- Thomas C. Duxbury
- Matthew P. Golombek
- Frank G. Lemoine
- Gregory A. Neumann
- David D. Rowlands
- Oded Aharonson
- Peter G. Ford
- Anton B. Ivanov
- Catherine L. Johnson
- Patrick J. McGovern
- James B. Abshire
- Robert S. Afzal
- Xiaoli Sun
- Journal of Geophysical Research: Planets
-  23689-23722
-  1 October 2001
free accessContext Camera Investigation on board the Mars Reconnaissance Orbiter
- Michael C. Malin
- James F. Bell
- Bruce A. Cantor
- Michael A. Caplinger
- Wendy M. Calvin
- R. Todd Clancy
- Kenneth S. Edgett
- Lawrence Edwards
- Robert M. Haberle
- Philip B. James
- Steven W. Lee
- Michael A. Ravine
- Peter C. Thomas
- Michael J. Wolff
- Journal of Geophysical Research: Planets
-  18 May 2007
free accessCompact Reconnaissance Imaging Spectrometer for Mars (CRISM) on Mars Reconnaissance Orbiter (MRO)
- S. Murchie
- R. Arvidson
- P. Bedini
- K. Beisser
- J.‐P. Bibring
- J. Bishop
- J. Boldt
- P. Cavender
- T. Choo
- R. T. Clancy
- E. H. Darlington
- D. Des Marais
- R. Espiritu
- D. Fort
- R. Green
- E. Guinness
- J. Hayes
- C. Hash
- K. Heffernan
- J. Hemmler
- G. Heyler
- D. Humm
- J. Hutcheson
- N. Izenberg
- R. Lee
- J. Lees
- D. Lohr
- E. Malaret
- T. Martin
- J. A. McGovern
- P. McGuire
- R. Morris
- J. Mustard
- S. Pelkey
- E. Rhodes
- M. Robinson
- T. Roush
- E. Schaefer
- G. Seagrave
- F. Seelos
- P. Silverglate
- S. Slavney
- M. Smith
- W.‐J. Shyong
- K. Strohbehn
- H. Taylor
- P. Thompson
- B. Tossman
- M. Wirzburger
- M. Wolff
- Journal of Geophysical Research: Planets
-  30 May 2007
free accessImproved general circulation models of the Martian atmosphere from the surface to above 80 km
- François Forget
- Frédéric Hourdin
- Richard Fournier
- Christophe Hourdin
- Olivier Talagrand
- Matthew Collins
- Stephen R. Lewis
- Peter L. Read
- Jean‐Paul Huot
- Journal of Geophysical Research: Planets
-  24155-24175
-  1 October 1999
free accessMars Global Surveyor Thermal Emission Spectrometer experiment: Investigation description and surface science results
- P. R. Christensen
- J. L. Bandfield
- V. E. Hamilton
- S. W. Ruff
- H. H. Kieffer
- T. N. Titus
- M. C. Malin
- R. V. Morris
- M. D. Lane
- R. L. Clark
- B. M. Jakosky
- M. T. Mellon
- J. C. Pearl
- B. J. Conrath
- M. D. Smith
- R. T. Clancy
- R. O. Kuzmin
- T. Roush
- G. L. Mehall
- N. Gorelick
- K. Bender
- K. Murray
- S. Dason
- E. Greene
- S. Silverman
- M. Greenfield
- Journal of Geophysical Research: Planets
-  23823-23871
-  1 October 2001
free accessMajor lunar crustal terranes: Surface expressions and crust‐mantle origins
- Journal of Geophysical Research: Planets
-  4197-4216
-  1 February 2000
free accessMars Global Surveyor Mars Orbiter Camera: Interplanetary cruise through primary mission
- Journal of Geophysical Research: Planets
-  23429-23570
-  1 October 2001
Open accessOrganic molecules in the Sheepbed Mudstone, Gale Crater, Mars
- C. Freissinet
- D. P. Glavin
- P. R. Mahaffy
- K. E. Miller
- J. L. Eigenbrode
- R. E. Summons
- A. E. Brunner
- A. Buch
- C. Szopa
- P. D. Archer
- H. B. Franz
- S. K. Atreya
- W. B. Brinckerhoff
- M. Cabane
- P. Coll
- P. G. Conrad
- D. J. Des Marais
- J. P. Dworkin
- A. G. Fairén
- P. François
- J. P. Grotzinger
- S. Kashyap
- I. L. ten Kate
- L. A. Leshin
- C. A. Malespin
- M. G. Martin
- F. J. Martin‐Torres
- A. C. McAdam
- D. W. Ming
- R. Navarro‐González
- A. A. Pavlov
- B. D. Prats
- S. W. Squyres
- A. Steele
- J. C. Stern
- D. Y. Sumner
- B. Sutter
- M.‐P. Zorzano
- the MSL Science Team
- Journal of Geophysical Research: Planets
-  495-514
-  4 March 2015
Key Points
- First in situ evidence of nonterrestrial organics in Martian surface sediments
- Chlorinated hydrocarbons identified in the Sheepbed mudstone by SAM
- Organics preserved in sample exposed to ionizing radiation and oxidative condition
free accessSpace weathering from Mercury to the asteroid belt
- Journal of Geophysical Research: Planets
-  10039-10073
-  1 May 2001
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Identifying an index of subsurface volatiles on Mars through an analysis of impact crater morphometry using principal component analysis
- Journal of Geophysical Research: Planets
-  2084-2101
-  4 November 2015
Key Points
- Principal component analysis is applied to crater morphometric and morphologic properties
- Principal components are related to the impactor, nature of primary target, and secondary processes
- Relative depth of subsurface ice is mapped
free accessCohesions, friction angles, and other physical properties of Martian regolith from Mars Exploration Rover wheel trenches and wheel scuffs
- Journal of Geophysical Research: Planets
-  23 February 2011
Open accessSeasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars
- Melissa G. Trainer
- Michael H. Wong
- Timothy H. McConnochie
- Heather B. Franz
- Sushil K. Atreya
- Pamela G. Conrad
- Franck Lefèvre
- Paul R. Mahaffy
- Charles A. Malespin
- Heidi L.K. Manning
- Javier Martín‐Torres
- Germán M. Martínez
- Christopher P. McKay
- Rafael Navarro‐González
- Álvaro Vicente‐Retortillo
- Christopher R. Webster
- María‐Paz Zorzano
- Journal of Geophysical Research: Planets
-  3000-3024
-  12 November 2019
Key Points
- First multiyear in situ measurements of the major components of the Mars atmosphere have been obtained by the MSL/SAM investigation
- Seasonal variation of CO2, N2, and Ar reveals differences in atmospheric transport and mixing timescales
- Oxygen varies seasonally and interannually, independently from Ar and N2, on timescales too fast to be explained by known chemistry
Plain Language Summary
The atmosphere of Mars is made up of primarily carbon dioxide, and during the Martian year, the barometric pressure is known to cycle up and down substantially as this carbon dioxide freezes out and then is rereleased from polar caps. The Mars Science Laboratory Curiosity rover has now acquired atmospheric composition measurements at the ground over multiple years, capturing the variations in the major gases over several seasonal cycles for the first time. With the Sample Analysis at Mars instrument, the annual average composition in Gale Crater was measured as 95.1% carbon dioxide, 2.59% nitrogen, 1.94% argon, 0.161% oxygen, and 0.058% carbon monoxide. However, the abundances of some of these gases were observed to vary up to 40% throughout the year due to the seasonal cycle. Nitrogen and argon follow the pressure changes but with a delay, indicating that transport of the atmosphere from pole to pole occurs on faster timescales than mixing of the components. Oxygen has been observed to show significant seasonal and year‐to‐year variability, suggesting an unknown atmospheric or surface process at work. These data can be used to better understand how the surface and atmosphere interact as we search for signs of habitability.
Open accessOrganic molecules in the Sheepbed Mudstone, Gale Crater, Mars
- C. Freissinet
- D. P. Glavin
- P. R. Mahaffy
- K. E. Miller
- J. L. Eigenbrode
- R. E. Summons
- A. E. Brunner
- A. Buch
- C. Szopa
- P. D. Archer
- H. B. Franz
- S. K. Atreya
- W. B. Brinckerhoff
- M. Cabane
- P. Coll
- P. G. Conrad
- D. J. Des Marais
- J. P. Dworkin
- A. G. Fairén
- P. François
- J. P. Grotzinger
- S. Kashyap
- I. L. ten Kate
- L. A. Leshin
- C. A. Malespin
- M. G. Martin
- F. J. Martin‐Torres
- A. C. McAdam
- D. W. Ming
- R. Navarro‐González
- A. A. Pavlov
- B. D. Prats
- S. W. Squyres
- A. Steele
- J. C. Stern
- D. Y. Sumner
- B. Sutter
- M.‐P. Zorzano
- the MSL Science Team
- Journal of Geophysical Research: Planets
-  495-514
-  4 March 2015
Key Points
- First in situ evidence of nonterrestrial organics in Martian surface sediments
- Chlorinated hydrocarbons identified in the Sheepbed mudstone by SAM
- Organics preserved in sample exposed to ionizing radiation and oxidative condition
free accessTitan's atmosphere and climate
- Journal of Geophysical Research: Planets
-  432-482
-  6 March 2017
Key Points
- Titan has the most complex atmospheric chemistry in the solar system
- Titan's atmosphere and surface share a unique connection
- Titan is the best place in the solar system to test ideas about the diversity and ubiquity of life
Plain Language Summary
Titan, the largest moon of Saturn, is unique in our solar system. It is the only moon with a dense atmosphere and the only other thick nitrogen atmosphere besides that of Earth. In the atmosphere very complicated chemistry, started by sunlight, forms molecules made of carbon, hydrogen, nitrogen, and oxygen (sometimes called “organic” molecules); these molecules end up on the surface where they are moved by wind and rain to form dunes, lakes, and seas. It is the only world besides Earth that has lakes and seas presently on its surface, although they are made of liquid methane and ethane instead of water. The conditions in Titan's atmosphere are ideal for creation of smog‐like particles called haze, which may have molecules that are important for the origin of life. The combination of liquid and organics means that Titan may be the best place in the solar system to test ideas about how life begins and how common it is in the universe. The Cassini‐Huygens mission to the Saturn system has provided a wealth of new information allowing us to study Titan as a system. Here I review our current understanding of Titan's atmosphere and climate forged from the powerful combination of Earth‐based observations, measurements from spacecraft, laboratory experiments, and computer models. I conclude with some of our remaining unanswered questions as the incredible era of exploration with Cassini‐Huygens comes to an end.
free accessDouble jeopardy in astronomy and planetary science: Women of color face greater risks of gendered and racial harassment
- Journal of Geophysical Research: Planets
-  1610-1623
-  10 July 2017
Key Points
- Women of color in this sample of astronomers and planetary scientists experience greater gender and racial harassment than any other group
- Women of color in this sample report feeling unsafe in their workplace due to gender (40%) and race (28%)
- Women of color and white women in this sample skip professional events due to feeling unsafe, leading to a loss of career opportunities
Plain Language Summary
Women generally, and women of color specifically, have reported hostile workplace experiences in astronomy and related fields for some time. However, little is known of the extent to which individuals in these disciplines experience inappropriate remarks, harassment, and assault. We conducted an internet‐based survey of the workplace experiences of 474 astronomers and planetary scientists between 2011 and 2015. In this sample, in nearly every significant finding, women of color experienced the highest rates of negative workplace experiences, including harassment and assault. Further, women of color reported feeling unsafe in the workplace as a result of their gender or sex 40% of the time, and as a result of their race 28% of the time. Finally, 18% of women of color, and 12% of white women, skipped professional events because they did not feel safe attending, identifying a significant loss of career opportunities due to a hostile climate. Our results suggest that certain community members may be at additional risk of hostile workplace experiences due to their gender, race, or both.
free accessTides on the Moon: Theory and determination of dissipation
- Journal of Geophysical Research: Planets
-  689-724
-  26 February 2015
Key Points
- Tidal Love number and quality factor Q depend on period
- Tidal dissipation 1/Q peaks at periods of a few months and decreases beyond
- Absorption band and narrow relaxation time models fit lunar tidal dissipation
free accessSelection of the Mars Exploration Rover landing sites
- M. P. Golombek
- J. A. Grant
- T. J. Parker
- D. M. Kass
- J. A. Crisp
- S. W. Squyres
- A. F. C. Haldemann
- M. Adler
- W. J. Lee
- N. T. Bridges
- R. E. Arvidson
- M. H. Carr
- R. L. Kirk
- P. C. Knocke
- R. B. Roncoli
- C. M. Weitz
- J. T. Schofield
- R. W. Zurek
- P. R. Christensen
- R. L. Fergason
- F. S. Anderson
- J. W. Rice
- Journal of Geophysical Research: Planets
-  10 December 2003
Pluto's Beating Heart Regulates the Atmospheric Circulation: Results From High‐Resolution and Multiyear Numerical Climate Simulations
- T. Bertrand
- F. Forget
- O. White
- B. Schmitt
- S. A. Stern
- H. A. Weaver
- L. A. Young
- K. Ennico
- C. B. Olkin
- the New Horizons Science Team
- Journal of Geophysical Research: Planets
-  4 February 2020
Key Points
- High‐resolution simulations of Pluto's climate show that the circulation is dominated by
10‐m/s retrograde winds during most of the year
- Nitrogen condensation‐sublimation flows in Sputnik Planitia are creating an intense western boundary current
- Atmospheric heat flux, transport of tholins, and albedo feedbacks could explain the albedo contrasts observed in Sputnik Planitia
Open accessGeological Evidence of Planet‐Wide Groundwater System on Mars
- Journal of Geophysical Research: Planets
-  374-395
-  21 January 2019
Key Points
- Geological evidence supporting Martian planet‐wide groundwater upwelling
- Water‐saturated zone intercepted by basins reaching more than ‐4000m below the Mars DATUM
- Putative relations between groundwater‐saturated level (groundwater‐fed lakes) and the ocean shorelines around ‐4000m below the DATUM
Plain Language Summary
Most previous studies on Mars relevant groundwater have proposed models, but few have looked at the geological evidence of groundwater upwelling in deep closed basins in the northern hemisphere equatorial region. Geological evidence of groundwater upwelling in these deep basins is a key point that will help to validate present‐day models and to better constraint them in the future. Observations in the northern hemisphere show evidence of a planet‐wide groundwater system on Mars. The elevations of these water‐related morphologies in all studied basins lie within the same narrow range of depths below Mars datum and notably coincide with the elevation of some ocean shorelines proposed by previous authors.




![Entropy in the equatorial plane of a synestia in the aftermath of a collision between two approximately half Earth mass planetary embryos. Credit: Carter et al. [2019], Figure 8 alternative text](/pb-assets/assets/AGU Carousels/March update/JE Mar 2020 Carousel 2-1583874275293.png)




![Launch of a drone towards a dust devil in the Alvord Desert, Oregon. Credit: Jackson et al. [2020], Figure 3a alternative text](/pb-assets/assets/AGU Carousels/March update/JE Mar 2020 Carousel 7-1583874277857.jpg)

![Panorama of the surface of the Moon seen by the Yutu-2 rover on its fourth day of operation. Lin et al. [2020], Figure 2 alternative text](/pb-assets/assets/AGU Carousels/March update/JE Mar 2020 Carousel 9-1583874279447.jpg)