Timothy Neal Titus, Ph.D.
Timothy Titus is a Research Space Scientist at the Astrogeology Science Center.
Tim studies Mars Polar Processes, focusing on the CO2 cycle and polar energy balance, as well as Mars thermal inertia investigations using 2-layer thermal inertia models to detect subsurface ice. He also studies Mars dunes, and cave detection on Earth, the Moon and Mars using thermal infrared remote sensing. Tim is currently using ALMA data to study the surface properties of asteroids.
Tim also studies Planetary Defense, where he brings to bear his experience as former Director of Logistics for Emergency Response for the Arizona National Guard. He is exploring the use of preexisting hazard models to explore possible regional and cascading effects from future asteroid impact events.
Professional Experience
Research Space Scientist - U.S. Geological Survey, Flagstaff AZ. 1999 - Present.
Acting Science Center Director - U.S. Geological Survey, Flagstaff AZ. Oct 2010 - Jan 2011.
Remote Sensing Analyst - Contracted with the U.S. Geological Survey, Flagstaff, AZ, and Oak Ridge Associated Universities, Oak Ridge, TN. 1997-1999.
Staff Lecturer - University of Wyoming, Laramie, WY. 1996-1997.
Co-Investigator on Mars Odyssey THermal EMission Imaging System (THEMIS).
Co-Investigator on Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectrometer for Mars (CRISM).
Selected as a Dawn at Vesta Participating Scientist.
Military: Lieutenant Colonel (Retired). Last Position prior to Retirement: Chief of Logistics, Camp Navajo, Arizona National Guard, Bellemont, AZ.
Education and Certifications
Ph.D.,Astrophysics, University of Wyoming, Laramie, WY, 1996
M.S., Astrophysics, Iowa State University, Ames, IA, 1988
B.A., Physics/Mathematics, Drake University, Des Moines, IA, 1985
Military Education: Command General Staff College (2000)
Military Education: Quartermaster Officer Advance Course (2003)
Science and Products
Survey of TES high albedo events in Mars' northern polar craters
Mars global digital dune database and initial science results
CO2 jets formed by sublimation beneath translucent slab ice in Mars' seasonal south polar ice cap
Shocked plagioclase signatures in Thermal Emission Spectrometer data of Mars
THEMIS VIS and IR observations of a high-altitude Martian dust devil
Thermal infrared and visual observations of a water ice lag in the Mars southern summer
A microphysically-based approach to modeling emissivity and albedo of the martian seasonal caps
Albedo of the south pole on Mars determined by topographic forcing of atmosphere dynamics
Evidence for subsurface water ice in Korolev crater, Mars
The carbon dioxide cycle
Exploring Martian polar atmospheric circulation and surface interactions
Mars: Water, water everywhere
Science and Products
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Filter Total Items: 90
Survey of TES high albedo events in Mars' northern polar craters
Following the work exploring Korolev Crater (Armstrong et al., 2005) for evidence of crater interior ice deposits, we have conducted a survey of Thermal Emission Spectroscopy (TES) temperature and albedo measurements for Mars' northern polar craters larger than 10 km. Specifically, we identify a class of craters that exhibits brightening in their interiors during a solar longitude, Ls, of 60 to 12AuthorsJ.C. Armstrong, S.K. Nielson, Timothy N. TitusMars global digital dune database and initial science results
A new Mars Global Digital Dune Database (MGD3) constructed using Thermal Emission Imaging System (THEMIS) infrared (IR) images provides a comprehensive and quantitative view of the geographic distribution of moderate‐ to large‐size dune fields (area >1 km2) that will help researchers to understand global climatic and sedimentary processes that have shaped the surface of Mars. MGD3 extends from 65°AuthorsRosalyn K. Hayward, Kevin F. Mullins, Lori K. Fenton, Trent M. Hare, Timothy N. Titus, Mary C. Bourke, Anthony Colaprete, Phillip R. ChristensenCO2 jets formed by sublimation beneath translucent slab ice in Mars' seasonal south polar ice cap
The martian polar caps are among the most dynamic regions on Mars, growing substantially in winter as a significant fraction of the atmosphere freezes out in the form of CO2 ice. Unusual dark spots, fans and blotches form as the south-polar seasonal CO2 ice cap retreats during spring and summer. Small radial channel networks are often associated with the location of spots once the ice disappears.AuthorsHugh H. Kieffer, Phillip R. Christensen, Timothy N. TitusShocked plagioclase signatures in Thermal Emission Spectrometer data of Mars
The extensive impact cratering record on Mars combined with evidence from SNC meteorites suggests that a significant fraction of the surface is composed of materials subjected to variable shock pressures. Pressure-induced structural changes in minerals during high-pressure shock events alter their thermal infrared spectral emission features, particularly for feldspars, in a predictable fashion. ToAuthorsJeffrey R. Johnson, Matthew I. Staid, Timothy N. Titus, Kris J. BeckerTHEMIS VIS and IR observations of a high-altitude Martian dust devil
The Mars Odyssey Thermal Emission Imaging System (THEMIS) imaged a Martian dust devil in both visible and thermal-infrared wavelengths on January 30, 2004. We believe this is the first documented infrared observation of an extraterrestrial dust devil, and the highest to be directly observed at more than 16 kilometers above the equatorial geoid of Mars. This dust devil measured over 700 meters in hAuthorsGlen Cushing, Timothy N. Titus, Phillip R. ChristensenThermal infrared and visual observations of a water ice lag in the Mars southern summer
We present thermal infrared and visual evidence for the existence of water ice lags in the early southern summer. The observed H2O‐ice lags lay in and near a chasma and appears to survive between 6–8 sols past the sublimation of the CO2. Possible sources of the H2O that compose the lag are (1) atmospheric H2O that is incorporated into the seasonal cap during condensation, (2) cold trapping of atmoAuthorsTimothy N. TitusA microphysically-based approach to modeling emissivity and albedo of the martian seasonal caps
A new model of albedo and emissivity of the martian seasonal caps represented as porous CO2 slabs containing spherical voids and dust particles is described. In the model, a radiative transfer model is coupled with a microphysical model in order to link changes in albedo and emissivity to changes in porosity caused by ice metamorphism. The coupled model is capable of reproducing temporal changes iAuthorsJanusz Eluszkiewicz, Jean-Luc Moncet, Timothy N. Titus, Gary B. HansenAlbedo of the south pole on Mars determined by topographic forcing of atmosphere dynamics
The nature of the martian south polar cap has remained enigmatic since the first spacecraft observations. In particular, the presence of a perennial carbon dioxide ice cap, the formation of a vast area of black ‘slab ice’ known as the Cryptic region and the asymmetric springtime retreat of the cap have eluded explanation. Here we present observations and climate modelling that indicate the south pAuthorsAnthony Colaprete, Jeffrey R. Barnes, Robert M. Haberle, Jeffery L. Hollingsworth, Hugh H. Kieffer, Timothy N. TitusEvidence for subsurface water ice in Korolev crater, Mars
Following the work of Kieffer and Titus (2001, Icarus 154, 162–180), we present results of thermal IR observations of Korolev crater, located at ∼73° latitude in the martian northern polar region. Similar to techniques employed by Titus et al. (2003, Science 299, 1048–1050), we use infrared images from the Thermal Emission Imaging System (THEMIS) aboard Mars Odyssey to identify several regions witAuthorsJohn C. Armstrong, Timothy N. Titus, Hugh H. KiefferThe carbon dioxide cycle
The seasonal CO2 cycle on Mars refers to the exchange of carbon dioxide between dry ice in the seasonal polar caps and gaseous carbon dioxide in the atmosphere. This review focuses on breakthroughs in understanding the process involving seasonal carbon dioxide phase changes that have occurred as a result of observations by Mars Global Surveyor.AuthorsPhilip B. James, Gary B. Hansen, Timothy N. TitusExploring Martian polar atmospheric circulation and surface interactions
The northern and southern seasonal polar caps of Mars are formed in the polar night, during their respective autumn and winter seasons, by the condensation of atmospheric CO2directly to the solid phase as ice, snow, and possibly frost. During spring and summer, the seasonal ice sublimes, returning CO2 to the atmosphere. The caps advance and recede in response to seasonal variations in solar insolaAuthorsThomas H. Prettyman, Timothy N. TitusMars: Water, water everywhere
Mars is a very watery planet, but all the water seems to be frozen. Divining the amount and distribution of this water, past and present, is essential for understanding martian climates, and more.AuthorsTimothy N. Titus - News