My dissertation is focused on Mars mid-latitude ice and what it can tell us about the Martian climate system, particularly the stability of water (at least in ice and vapor form)
in the Amazonian period.
In 2015, I published my study on an ice sheet the size of California and Texas combined just underneath the surface of Mars that goes as deep as a 13-story building. To find this
ice, I used a high-resolution camera called HiRISE, which we operate here at the Lunar and Planetary Lab on campus, as well as a radar instrument called SHARAD. Both of these instruments are onboard NASA's Mars Reconnaissance Orbiter. Creating 3D Digital Terrain Models of terraced craters (above) allowed me to constrain the thicknesses of the ice layering, and by
combining these measurements with the time delays of the subsurface radar returns, I was able to estimate the dielectric constant of this deposit.
Bramson et al. (2015) Widespread excess ice in Arcadia Planitia, Mars. GRL, 42,
More recently, I have written a 1D thermal conduction model to look into how this ice could have been preserved. We find that decameters-thick ice sheets at the mid-latitudes of
Mars can be orders of magnitude older than the obliquity cycles that are typically thought to drive mid-latitude ice deposition and sublimation. Retreat of this ice in the last 4
Myr could have contributed ~6% of the volume of the North Polar Layered Deposits (NPLD) and more than 10% if the NPLD are older than 4 Myr.
Bramson et al. (2017) Preservation of Mid-Latitude Ice Sheets on Mars. JGR-Planets, 112,
Ice in the mid-latitudes exchanges with polar ice over geologic time so to understand the other half of the system, I am applying my ice stability model to the migrating troughs of
Mars' Polar Layered Deposits. This will allow me to investigate the role of sublimation on the migration of these troughs, and the accumulation that would have
occured over the same period of time.
Additional topics and projects:
Radar and Remote Sensing
- Newly-discovered scarps that expose the stratigraphy of mid-latitude ice sheets on Mars [Dundas et al. (2018)]
- Radar detections of mid-latitude ice-rich deposits in the Southern hemisphere
- I am currently mentoring an undergraduate astronomy major, Claire Cook, through the Arizona Space Grant Consortium on
this project for her senior honors thesis.
- Application of super-resolution radar processing techniques to find thinner and shallower ice deposits on Mars (collaboration with Marco Mastrogiuseppe and Marìca Raguso)
- Arecibo radar-based models of asteroid shapes and surface properties: a comparison of ground-based observations of Itokawa to the 'ground truth' from the Hayabusa spacecraft mission (collaboration with Mike Nolan, Ellen Howell and Patrick Taylor)
Theoretical Modeling of Icy Processes
- iSALE modeling of the formation of terraced craters by impacts into icy targets (collaboration with Elena Martellato)
- Temperature-dependent modification of possible cryovolcanic features
- We predict a latitude-dependent asymmetry in equatorward vs. poleward facing slopes of cryovolcanic domes on Ceres due to temperature differences of these slopes
affecting the rates of viscous flow. Viscous flow rates are slow enough at the location of Ahuna Mons that it would remain identifiable as a cryovolcanic feature today,
given the expected young age of the dome [Sori et al. (2017a)] and can be used to constrain the cryovolcanic rates on Ceres throughout time [Sori et al. (submited)].
- Carbon dioxide ice transport and stability on the Uranian moons
- We predict the bright spot observed by Voyager 2 inside the crater Wunda is a deposit of CO2 ice.
[Sori et al. (2017b)]
- Origin of geologically recent flow units in Hrad Vallis, Mars: mega-lahars or pāhoehoe-like lava flows?
- We find evidence for both aqueous flooding and effusive volcanism suggesting the area has a complex hydrologic and geologic history. Pāhoehoe‐like lava flows could have interacted with ground ice in the region to generate meltwater and steam. [Hamilton et al. (2018)]
Terrestrial Analog Studies
- Ground-penetrating radar (GPR) and ice-coring of the Langjökull Glacier in Iceland, led by Lynn Carter and colleagues
- Mapping lava flow margins with differential GPS at Holuhraun, Iceland (led by Christopher Hamilton)
- Fractal dimension of lava flow margins at Craters of the Moon (project led by Ethan Schaefer, campaign run by NASA's FINESSE program)
- Synthesis team, 6th International Conference on Mars Polar Science and Exploration
- Helped summarize the content of the conference and progress made since the 5th conference to develop a list of outstanding questions facing the Mars Polar
community [Smith et al. (2018)]
- Spacecraft Mission Design, NASA JPL Planetary Science Summer Seminar
- Project Manager for our PSSS team in which we developed a mission concept for a Uranian orbiter featuring a low-cost instrument suite [Elder et al. (2018)]
This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1143953. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors(s) and do not necessarily reflect the views of the National Science Foundation.