A model of dust in the Martian lower atmosphere

Abstract

[1] A coupled boundary layer-Aeolian dust model of the Martian atmosphere is presented. This model was developed to determine how radiation (scattering, absorption, and emission) by dust affects the boundary layer and, in turn, how this affects the dust distribution in the atmosphere. This was achieved by coupling a planetary boundary layer (PBL) model with the 2007 dust model of P. A. Taylor et al. The principle motivation here is to determine whether it will be possible to use the lidar on board the Phoenix lander to detect the depth of the Martian boundary layer from the dust distribution. Runs were conducted for different dust profiles, roughness lengths, and geostrophic winds. These indicate that there should be a distinct horizon in dust concentration which will be detectable by the Phoenix lidar. The model is also applied to the 1977B dust storm optical data of Viking Lander 1, and our analysis indicates a significant improvement over previous 1-D studies of dust storm decay.

Ice nucleation by surrogates of Martian mineral dust: What can we learn about Mars without leaving Earth?

“…Furthermore:The mineral dust grains did not nucleate ice at SR i ~ 1, a value which has been assumed in some Martian atmospheric models [ Davy et al ., ]. S crit ~ 1.1 at 215 K determined here supports the assumption of Earth‐like IN by Michelangeli et al .…”

“…Simple assumptions include that of Davy et al . [], who treat the nucleation of clouds at exactly the equilibrium saturation and freezing point. Terrestrial analogies of cloud formation, in the absence of Martian samples and in situ measurements, include assumption of Earth‐like ice nuclei (IN) by Michelangeli et al .…”

The impact of surface dust source exhaustion on the martian dust cycle, dust storms and interannual variability, as simulated by the MarsWRF General Circulation Model

“…Rafkin et al, 2002;Michaels et al, 2006;Goldenson et al, 2008;Davy et al, 2009;Heavens et al, 2011;Rafkin, 2012). Observations of the vertical dust distribution (Heavens et al, 2011;Guzewich et al, 2013b) indicate elevated dust maxima, suggesting a much larger amount of non-local dust mixing than predicted by MRF PBL.…”

Simulating observed boundary layer clouds on Mars

“…The microphysical model is driven by the temperatures and vertical eddy diffusion coefficients calculated independently by the coupled PBL‐Aeolian dust model of Davy et al [2009] for //the Phoenix lander site (lat = 68.2°, lon = 234.2°) at solar longitude// Ls = 122° (Phoenix mission sol 99), see Figure 2a. For the simulations used here the PBL model was constrained to match the Phoenix air temperature measurements at a height of 2 meters above the surface [ Davy et al , 2010], and the upper level wind was prescribed as 5 m/s.…”

“…These challenges have been addressed in this study by applying a PBL model with high vertical resolution to provide temperature profiles [ Davy et al , 2009], and making use of the Phoenix LIDAR and Thermal and Electrical Conductivity Probe (TECP) [ Zent et al , 2010] measurements to estimate the profile of humidity [ Whiteway et al , 2009]. With this input the detailed microphysical ice cloud model produced a simulation of clouds and precipitation in the PBL that is in agreement with the observations.…”