Publications:
Hansen, C.J., S. Byrne, G. Portyankina, M. Bourke, C. Dundas, A. McEwen, M. Mellon, A. Pommerol, and N. Thomas, (2013), Observations of the northern seasonal polar cap on Mars: I. Spring sublimation activity and processes. Icarus, 225, 881-897, doi:10.1016/j.icarus.2012.09.024
Portyankina, G., A. Pommerol, K.-M. Aye, C.J. Hansen, and N. Thomas, (2013), Observations of the Northern seasonal polar cap on Mars II: HiRISE photometric analysis of evolution of northern polar dunes in spring, Icarus, 225, 898-910, doi: 10.1016/j.icarus.2012.10.017.
Pommerol, A., T. Appéré, G. Portyankina, K.?M. Aye, N. Thomas, and C.J. Hansen (2013), Observations of the Northern seasonal polar cap on Mars III: CRISM / HiRISE observations of spring sublimation, Icarus, 225, 911-922, doi:10.1016/j.icarus.2012.08.039
Portyankina, G., A. Pommerol, K.-M. Aye, C.J. Hansen, and N. Thomas, (2012) Polygonal cracks in the seasonal semi-translucent CO2 ice layer in Martian polar areas, J. Geophys. Res. (Planets), 117, Issue E2, CiteID E02006, doi: 10.1029/2011JE003917.
Thomas, N., G. Portyankina, C. J. Hansen, and A. Pommerol (2011), Sub-surface CO2 gas flow in Mars' polar regions: Gas transport under constant production rate conditions, Geophys. Res. Lett., 38, L08203, doi:10.1029/2011GL046797.
Pommerol, A., G. Portyankina, N. Thomas, K.-M. Aye, C.J. Hansen, M. Vincendon, and Y. Langevin, (2011) Evolution of south seasonal cap during Martian spring: insights from highresolution observations by HiRISE and CRISM/MRO, J. Geophys. Res. (Planets), 116, 8007, doi: 10.1029/2010JE003790.
Hansen, C.J., M. Bourke, N.T. Bridges, C. Colon, S. Diniega, C. Dundas, K. Herkenhoff, A. McEwen, M. Mellon, G. Portyankina, and N. Thomas, (2011), Seasonal Erosion and Restoration of Mars’ Northern Polar Dunes, Science, 331, 575-578, doi:10.1126/science.1197636.
Thomas, N., G. Portyankina, C.J. Hansen, and A. Pommerol, (2011), HiRISE observations of gas sublimation-driven activity in Mars' southern polar regions: IV. Fluid dynamics models of CO2 jets, Icarus, 212, 66-85, dx.doi.org/10.1016/j.icarus.2010.12.016