My research interests are in understanding the quantitative geomorphology of other planets. I am particularly interested in the physical processes related to ice and volatiles that affect the surfaces of solid bodies in our solar system. I enjoy tackling these problems using a combination of spacecraft remote sensing observations and theoretical modeling, supplemented by occasional field work at terrestrial analog sites and experimental studies.
Subsurface Water Ice Mapping (SWIM) in the Northern Hemisphere of Mars
The goal of the SWIM project is to provide a set of mapping products using existing spacecraft data that delineate subsurface ice in the mid-latitudes of Mars. We aim to identify and map indicators of possible subsurface ice in each data set and use a combination of all data sets to assess the likelihood of ice being present in shallow (less than 5 m depth) and deep (more than 5 m depth) zones. In this, we are developing the SWIM Equation, styled after the famous Drake Equation, which will provide maps of how consistent the data are with the presence or absence of water ice resources in the subsurface.
Click here to learn more about the SWIM Project!
Radar response of lunar cryptomaria and pyroclastic deposits in Mini-RF data
I am investigating the monostatic and bistatic radar response of cryptomaria and pyroclastic deposits in Mini-RF data, a side-looking hybrid-polarization radar system onboard the Lunar Reconnaissance Orbiter, with my postdoc advisor Dr. Carter. I am comparing and modeling the radar response of these terrains to other datasets (e.g. Clementine color ratios, Titanium map, etc.) and to the radar response of other terrains (e.g. Mare and Highlands).
Modeling and laboratory experiments of ice sintering processes in non-terrestrial environments
Our team, led by PI Dr. Jamie Molaro, is combining laboratory experiments and theoretical modeling to explore the role of sintering on the evolution of water ice on icy satellites, Mars, and across the solar system. I will be applying our experimentally-validated model to Mars to explore the role that diurnal and seasonal thermal cycling plays in sintering rates, and the formation of subsurface density gradients to explore how these processes may produce layering in martian ice deposits, and relate the results to spacecraft images and radar subsurface detections that show layering within Martian ice deposits.
Additional Topics and Projects:
Radar and Remote Sensing
- Arcadia Planitia, Mars
- Using SHARAD radar and 3D Digital Terrain Models of terraced craters from the HiRISE camera, we found an ice sheet the size of California and Texas combined just underneath the surface of this region of Mars that goes as deep as a 13-story building. [Bramson et al. (2015)]
- 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, Marìca Raguso, Than Putzig and Isaac Smith)
- 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
- Ice stability of mid-latitude ice sheets on Mars
- 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)]
- 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. (2018].
- 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)]
- Modeling role of sublimation in migration of Mars' polar spiral troughs [Bramson et al. (in review)]
- Conditions for basal melting of perchlorate-salt mixtures at the south pole of Mars [Sori and Bramson (accepted to GRL)]
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) [EOS Report]
- 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)]
- Updating our understanding of Mars' recent and present-day climate: scientific advancement and priorities for future investigations [Diniega et al. (accepted)]
Complete publications list available from: NASA ADS Author search Ali Bramson
Refereed publications (NASA ADS): Calendar Years 2016 through August 2018
Smith, I. B., Diniega, S., Beaty, D. W., Thorsteinsson, T., Becerra, P., Bramson, A. M., Clifford, S. M., Hvidberg, C. S., Portyankina, G., Piqueux, S., Spiga, A., Titus, T. N. 6th international conference on Mars polar science and exploration: Conference summary and five top questions 2018Icar..308....2S
Dundas, C. M., Bramson, A. M., Ojha, L., Wray, J. J., Mellon, M. T., Byrne, S., McEwen, A. S., Putzig, N. E., Viola, D., Sutton, S., Clark, E., Holt, J. W. Exposed subsurface ice sheets in the Martian mid-latitudes 2018Sci...359..199D
Bramson, A. M., Byrne, S., Bapst, J. Preservation of Midlatitude Ice Sheets on Mars 2017JGRE..122.2250B
Sori, M. M., Bapst, J., Bramson, A. M., Byrne, S., Landis, M. E. A Wunda-full world? Carbon dioxide ice deposits on Umbriel and other Uranian moons 2017Icar..290....1S
Sori, M. M., Byrne, S., Bland, M. T., Bramson, A. M., Ermakov, A. I., Hamilton, C. W., Otto, K. A., Ruesch, O., Russell, C. T. The vanishing cryovolcanoes of Ceres 2017GeoRL..44.1243S
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