Thermal and albedo mapping of Mars during the Viking primary mission

Abstract

Measurements of Martian emission and reflection reveal wide variations of surface properties and indicate the presence of a larger atmospheric contribution to the observed radiances than was anticipated. Temperatures observed during the Viking primary mission range from 130 to 290 K. Surface thermal inertias from 1.6 to 11×10−3 cal cm−2 s−1/2 K−1 are mapped, and they correlate with surficial geologic units. An equatorial map of bolometric albedo generally correlates with prior narrowband observations. These albedos range from 0.09 to 0.43; some regional brightenings are atmospheric in origin. The photometric behavior implies quasi‐Lambertian surface reflectance plus a strongly forward‐scattering atmosphere. Brightness temperatures at large emission angles are strongly influenced by atmospheric infrared opacity and by the presence of rocks on the surface. The correlation and grouping of albedo and thermal inertia indicate that there are two major components of Martian surface material, with bright regions having a fine particulate covering. Winter polar temperatures show spatial and temporal variations, suggesting variation of atmospheric composition; a strong atmospheric temperature inversion exists above the south polar cap during winter. Surface CO2 condensation may also occur locally near the equator before dawn. Rising temperatures before dawn in a region near Arsia Mons imply the presence of daily local water ice fogs.

High‐resolution thermal inertia mapping of Mars: Sites of exobiological interest

“…Similarly, the average or effective thermal conductivity would need to be 5-10 times higher than that of the Viking landing sites. If the high thermal inertia were produced by there being a high rock abundance on top of a dusty surface, roughly 3/4 of the surface would need to be covered with large rocks [Kieffer et al, 1977;Jakosky, 1979]. If the high values were obtained by adding rocks to a surface that had a duricrust similar to that at the Viking sites, it still would require that half of the surface be covered with rocks.…”

“…The thermal inertia of the surface is derived from the diurnal variation of surface temperature as determined from thermal emission measurements (for discussion, see Kieffer et al [1977], Jakosky [1979], Palluconi and Kieffer [1981], Haberle and Jakosky [1991 ], or Christensen and Moore [1992]). The diurnal variation of temperature is controlled predominantly by the thermal conductivity of the surface, K, through the thermal inertia, formally defined as I = (KpC)m; here, p is the bulk density of the surface material and C is its specific heat.…”

New evidence for a magmatic influence on the origin of Valles Marineris, Mars

“…We use a surface temperature of 220 K, the present-day mean surface temperature (Kieffer et al, 1977), and a thermal conductivity of the crust of 2 W m − 1 K − 1 (e.g., Grott et al, 2005). For the crustal heat production rate, we use potassium and thorium abundances of 3630 and 0.70 ppm, respectively, average values deduced from GRS data for the ancient southern highlands (Taylor et al, 2006).…”

Mars' “White Rock” feature lacks evidence of an aqueous origin: Results from Mars Global Surveyor

“…TES is equipped with a broadband visible to shortwave-infrared channel ( Thermal inertia is sensitive to the physical character below the surface to a depth corresponding to the penetration of the diurnal temperature wave [Kieffer et al, 1973[Kieffer et al, , 1977. This depth can range from a few centimeters to a few decimeters, being greater for materials with higher thermal inertias.…”