Curiosity observations and column model integrations for a martian global dust event

Abstract

The Curiosity observations of surface pressure, optical thickness (τ), and Mars Year 32 water column values (PWC) were used to force adsorptive column model simulations around the MY34 strong dust event. Hourly ground (Tg) and air temperatures and water vapor mixing ratios were used for model validation. The diurnal amplitude of Tg drops from 90 K to 30 K during thick dust (τ up to 7–8.5), then increases back to 90 K in the pace of τ decreasing back to seasonal average values. The model mimics the very large and rapid temperature changes quite well, strong dust downward IR emission being the dominant term in the surface heat budget during thick dust. Sensitivity tests indicate that the thick dust tends to show more solar forward scatter initially, consistent with larger particles. Water vapor mixing ratios are lower than normal before and after the event but a lot higher during it. The required local PWC at Gale is 2–3 μm lower than during the low-dust MY32 before and after the dust event, but about 7–8 μm higher during the peak of it.