TES Mapping of Mars' North Seasonal Cap

Carbon dioxide ice clouds, snowfalls, and baroclinic waves in the northern winter polar atmosphere of Mars

“…The northern polar cap extends to 60°N at the spring equinox, recesses almost linearly during the spring, and disappears at the summer solstice, leaving only the residual cap that consists of water ice [Cantor et al, 1998;Iwasaki et al, 1999;James and Cantor, 2001]. Observations using the Thermal Emission Spectrometer (TES) [Kieffer and Titus, 2001] and the Mars Orbiter Laser Altimeter (MOLA) [Smith et al, 2001], onboard the Mars Global Surveyor (MGS) spacecraft, indicate that the accumulated CO 2 ice in snow at the seasonal northern cap is up to 1.5 m deep.…”

Introduction to the 4th Mars Polar Science and Exploration Conference special issue: Five top questions in Mars polar science

“…The seasonal CO 2 cycle, including formation of the seasonal caps, has been extensively studied (recent references include, e.g., James and Cantor, 2001;Kieffer and Titus, 2001;Smith et al, 2001;Piquex et al, 2003;Douté et al, 2006). Each year, seasonal insolation variations result in about 25% of the martian atmosphere alternatively condensing and sublimating from the poles.…”

“…This seasonal cycling of CO 2 is driven primarily by insolation variations, as first predicted by Leighton and Murray (1966). The present-day seasonal cycling of CO 2 has been investigated using energy balance and General Circulation Models and by tracking seasonal cap changes in: surface neutron flux (GRS; e.g., Feldman et al, 2003), surface topography (MOLA; e.g., Smith et al, 2001;Aharonson et al, 2004), thermal inertia (TES; e.g., Kieffer and Titus, 2001), and ice grain size inferred from imaging spectrometer observations (OMEGA; e.g., Langevin et al, 2005). However, while the overall behavior and composition of the seasonal cap is wellknown, the thickness measurements have a precision close to the actual seasonal cap thickness, so that its mass balance has not yet been determined.…”

“…Surface deposition of H 2 O and dust occurs together with seasonal deposition of CO 2 . Atmospheric dust raised from the surface by dust storms is thought to act as condensation nuclei for the water vapor and atmospheric CO 2 (Kieffer and Titus, 2001). In autumn, H 2 O and CO 2 condense on the dust particles and precipitate to the surface (reviewed in Clifford et al, 2000a).…”

“…Various observations indicate that the north polar residual ice cap (NRC) is composed largely of water ice (Kieffer et al, 1976;Kieffer and Titus, 2001;Langevin et al, 2005). However, the albedo of the NRC surface is variable, with values consistently slightly less than that for pure water ice (Bass et al, 2000;James and Cantor, 2001;Kieffer and Titus, 2001;Malin and Edgett, 2001;Hale et al, 2005).…”