Dust Layering in the Atmosphere of Mars Observed by the Phoenix LIDAR and Explained Using a General Circulation Model

Friday, 19 December 2014: 2:50 PM
James A Whiteway1, Frank Daerden2, Leonce Komguem1 and Lori Neary3, (1)York University, Toronto, ON, Canada, (2)BIRA-IASB, Brussels, Belgium, (3)BIRA/IASB, Brussels, Belgium
The LIDAR instrument on the Phoenix mission obtained measurements of atmospheric dust and clouds from the surface in the Arctic region of Mars during late-spring through mid-summer. The observed vertical distribution of dust indicated that the planetary boundary layer (PBL) was evenly mixed up to heights of 4 km by daytime convection and turbulence. The dust loading within the PBL was a maximum around summer solstice and then declined over the next 60 Martian days (sols). Detached layers of dust were also detected above the top of the PBL around summer solstice. An atmospheric general circulation model (GCM) was applied to simulate the variability in the total dust loading and the detached layers. The model showed that the enhanced dust loading and the detached layers around summer solstice could be traced back to dust storm activity near the edge of the north polar ice cap. The mechanisms for producing the detached dust layers will be described.