Kaj Williams, Ph.D.
My expertise is in developing and applying mathematical and computational methods for understanding physical processes on planetary surfaces and atmospheres.
Science and Products
Filter Total Items: 17
Mars Astrobiological Cave and Internal habitability Explorer (MACIE): A New Frontiers mission concept Mars Astrobiological Cave and Internal habitability Explorer (MACIE): A New Frontiers mission concept
Martian subsurface habitability and astrobiology can be evaluated via a lava tube cave, without drilling. MACIE addresses two key goals of the Decadal Survey (2013–2022) and three MEPAG goals. New advances in robotic architectures, autonomous navigation, target sample selection, and analysis will enable MACIE to explore the Martian subsurface.
Authors
C. M. Phillips-Lander, A. Agha-mohamamdi, J. Wynne, Timothy Titus, N. Chanover, C. Demirel-Floyd, Kyle Uckert, Kaj Williams, D Wyrick, J. Blank, Penelope Boston, K. Mitchell, A Kereszturi, J. Martin-Torres, S. Shkolyar, N. Bardabelias, S. Datta, K. Retherford, Lydia Sam, A. Bahardwaj, A. Fairen, D. Flannery, Roger Wiens
Widespread exposures of extensive clean shallow ice in the mid-latitudes of Mars Widespread exposures of extensive clean shallow ice in the mid-latitudes of Mars
Although ice in the Martian midlatitudes is typically covered by a layer of dust or regolith, it is exposed in some locations by fresh impact craters or in erosional scarps. In both cases, the exposed ice is massive or excess ice with a low lithic content. We find that erosional scarps occur between 50° and 61° north and south latitude and that they are concentrated in and near...
Authors
Colin Dundas, Michael Mellon, Susan Conway, Ingrid Daubar, Kaj Williams, Lujendra Ojha, James Wray, Ali Bramson, Shane Byrne, Alfred McEwen, Liliya Posiolova, Gunnar Speth, Donna Viola, Margaret E. Landis, Gareth Morgan, Asmin Pathare
Conceptual model for the removal of cold-trapped H2O ice on the Mars northern seasonal springtime polar cap Conceptual model for the removal of cold-trapped H2O ice on the Mars northern seasonal springtime polar cap
The transport of H2O ice along the retreating north polar seasonal CO2 ice cap has previously been modeled and observed. Spectral observations show that H2O ice forms on the interior of the seasonal cap, while thermal observations show these regions to be consistent with CO2 ice. Prior to the sublimation of the seasonal CO2, the observed H2O ice deposits are diminished—and because H2O...
Authors
Timothy Titus, Kaj Williams, Glen Cushing
The effects of snow and salt on ice table stability in University Valley, Antarctica The effects of snow and salt on ice table stability in University Valley, Antarctica
The Antarctic Dry Valleys represent a unique environment where it is possible to study dry permafrost overlaying an ice-rich permafrost. In this paper, two opposing mechanisms for ice table stability in University Valley are addressed: i) diffusive recharge via thin seasonal snow deposits and ii) desiccation via salt deposits in the upper soil column. A high-resolution time-marching soil...
Authors
Kaj Williams, Jennifer Heldmann, Christopher McKay, Michael Mellon
Martian cave air-movement via Helmholtz resonance Martian cave air-movement via Helmholtz resonance
Infrasonic resonance has previously been measured in terrestrial caves by other researchers, where Helmholtz resonance has been suggested as the plausible mechanism resulting in periodic wind reversals within cave entrances. We extend this reasoning to possible Martian caves, where we examine the characteristics of four atypical pit craters (APCs) on Tharsis, suggested as candidate cave...
Authors
Kaj Williams, Timothy Titus, Chris Okubo, Glen Cushing
Non-USGS Publications**
Williams, Kaj, Christopher P. McKay and J.L Heldmann. (2015) Modeling the effects of Martian surface frost on ice table depth. Icarus, 261, 58-65.
Williams, Kaj and Chris McKay. (2015). Comparing flow-through and static ice cave models for Shoshone Ice Cave. International Journal of Speleology, 44: 1.
Heldmann, J. L., W. Pollard, C. P. Mckay, M. M. Marinova, A. Davila, K. E. Williams, D. Lacelle, and D. T. Andersen (2013), The high elevation Dry Valleys in Antarctica as analog sites for subsurface ice on Mars, Planetary and Space Science, 85(C), doi:10.1016/j.pss.2013.05.019.
J.L. Heldmann, M. Marinova, K.E. Williams, D. Lacelle, C.P. McKay, A. Davila, W. Pollard and D.T. Andersen (2012). Formation and evolution of buried snowpack deposits in Pearse Valley, Antarctica, and implications for Mars. Antarctic Science, 24, doi:10.1017/S0954102011000903
Williams, K. E., McKay, C. P. and Persson, F. (2012) The surface energy balance at the Huygens Landing site and the moist surface conditions on Titan. Planetary and Space Science. Vol 60, nr. 1.
Williams, K. E., Pappalardo, R. T. (2011) Variability in the Small Crater Population of Callisto. Icarus 215,1.
Williams, K.E., McKay, C. P., Toon, O.B., Head, J. W. (2010) Do Ice Caves Exist on Mars? Icarus 209,2.
Williams, K.E., Toon, O. B., Heldmann, J. L., Mellon, M. (2009) Ancient melting of mid-latitude snowpacks on Mars as a water source for gullies, Icarus, 200.
Williams, K.E., Toon, O.B., Heldmann, J.L. , McKay C.P. and Mellon, M. (2008) Stability of Mid-Latitude Snowpacks on Mars, Icarus, 196.
Williams, K. E., O. B. Toon, and J. Heldmann (2007), Modeling water ice lifetimes at recent Martian gully locations, Geophys. Res. Lett., 34, L09204, doi:10.1029/2007GL029507.
Lai, Y.C., Lerner, D, Williams, K and Crebogi, C. (Nov. 1999) Unstable dimension variability in coupled chaotic systems. Physical Review E 60 (5): 5445-5454 : A.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 17
Mars Astrobiological Cave and Internal habitability Explorer (MACIE): A New Frontiers mission concept Mars Astrobiological Cave and Internal habitability Explorer (MACIE): A New Frontiers mission concept
Martian subsurface habitability and astrobiology can be evaluated via a lava tube cave, without drilling. MACIE addresses two key goals of the Decadal Survey (2013–2022) and three MEPAG goals. New advances in robotic architectures, autonomous navigation, target sample selection, and analysis will enable MACIE to explore the Martian subsurface.
Authors
C. M. Phillips-Lander, A. Agha-mohamamdi, J. Wynne, Timothy Titus, N. Chanover, C. Demirel-Floyd, Kyle Uckert, Kaj Williams, D Wyrick, J. Blank, Penelope Boston, K. Mitchell, A Kereszturi, J. Martin-Torres, S. Shkolyar, N. Bardabelias, S. Datta, K. Retherford, Lydia Sam, A. Bahardwaj, A. Fairen, D. Flannery, Roger Wiens
Widespread exposures of extensive clean shallow ice in the mid-latitudes of Mars Widespread exposures of extensive clean shallow ice in the mid-latitudes of Mars
Although ice in the Martian midlatitudes is typically covered by a layer of dust or regolith, it is exposed in some locations by fresh impact craters or in erosional scarps. In both cases, the exposed ice is massive or excess ice with a low lithic content. We find that erosional scarps occur between 50° and 61° north and south latitude and that they are concentrated in and near...
Authors
Colin Dundas, Michael Mellon, Susan Conway, Ingrid Daubar, Kaj Williams, Lujendra Ojha, James Wray, Ali Bramson, Shane Byrne, Alfred McEwen, Liliya Posiolova, Gunnar Speth, Donna Viola, Margaret E. Landis, Gareth Morgan, Asmin Pathare
Conceptual model for the removal of cold-trapped H2O ice on the Mars northern seasonal springtime polar cap Conceptual model for the removal of cold-trapped H2O ice on the Mars northern seasonal springtime polar cap
The transport of H2O ice along the retreating north polar seasonal CO2 ice cap has previously been modeled and observed. Spectral observations show that H2O ice forms on the interior of the seasonal cap, while thermal observations show these regions to be consistent with CO2 ice. Prior to the sublimation of the seasonal CO2, the observed H2O ice deposits are diminished—and because H2O...
Authors
Timothy Titus, Kaj Williams, Glen Cushing
The effects of snow and salt on ice table stability in University Valley, Antarctica The effects of snow and salt on ice table stability in University Valley, Antarctica
The Antarctic Dry Valleys represent a unique environment where it is possible to study dry permafrost overlaying an ice-rich permafrost. In this paper, two opposing mechanisms for ice table stability in University Valley are addressed: i) diffusive recharge via thin seasonal snow deposits and ii) desiccation via salt deposits in the upper soil column. A high-resolution time-marching soil...
Authors
Kaj Williams, Jennifer Heldmann, Christopher McKay, Michael Mellon
Martian cave air-movement via Helmholtz resonance Martian cave air-movement via Helmholtz resonance
Infrasonic resonance has previously been measured in terrestrial caves by other researchers, where Helmholtz resonance has been suggested as the plausible mechanism resulting in periodic wind reversals within cave entrances. We extend this reasoning to possible Martian caves, where we examine the characteristics of four atypical pit craters (APCs) on Tharsis, suggested as candidate cave...
Authors
Kaj Williams, Timothy Titus, Chris Okubo, Glen Cushing
Non-USGS Publications**
Williams, Kaj, Christopher P. McKay and J.L Heldmann. (2015) Modeling the effects of Martian surface frost on ice table depth. Icarus, 261, 58-65.
Williams, Kaj and Chris McKay. (2015). Comparing flow-through and static ice cave models for Shoshone Ice Cave. International Journal of Speleology, 44: 1.
Heldmann, J. L., W. Pollard, C. P. Mckay, M. M. Marinova, A. Davila, K. E. Williams, D. Lacelle, and D. T. Andersen (2013), The high elevation Dry Valleys in Antarctica as analog sites for subsurface ice on Mars, Planetary and Space Science, 85(C), doi:10.1016/j.pss.2013.05.019.
J.L. Heldmann, M. Marinova, K.E. Williams, D. Lacelle, C.P. McKay, A. Davila, W. Pollard and D.T. Andersen (2012). Formation and evolution of buried snowpack deposits in Pearse Valley, Antarctica, and implications for Mars. Antarctic Science, 24, doi:10.1017/S0954102011000903
Williams, K. E., McKay, C. P. and Persson, F. (2012) The surface energy balance at the Huygens Landing site and the moist surface conditions on Titan. Planetary and Space Science. Vol 60, nr. 1.
Williams, K. E., Pappalardo, R. T. (2011) Variability in the Small Crater Population of Callisto. Icarus 215,1.
Williams, K.E., McKay, C. P., Toon, O.B., Head, J. W. (2010) Do Ice Caves Exist on Mars? Icarus 209,2.
Williams, K.E., Toon, O. B., Heldmann, J. L., Mellon, M. (2009) Ancient melting of mid-latitude snowpacks on Mars as a water source for gullies, Icarus, 200.
Williams, K.E., Toon, O.B., Heldmann, J.L. , McKay C.P. and Mellon, M. (2008) Stability of Mid-Latitude Snowpacks on Mars, Icarus, 196.
Williams, K. E., O. B. Toon, and J. Heldmann (2007), Modeling water ice lifetimes at recent Martian gully locations, Geophys. Res. Lett., 34, L09204, doi:10.1029/2007GL029507.
Lai, Y.C., Lerner, D, Williams, K and Crebogi, C. (Nov. 1999) Unstable dimension variability in coupled chaotic systems. Physical Review E 60 (5): 5445-5454 : A.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.