Surface Warming During the 2018/Mars Year 34 Global Dust Storm.

Area of Science:

• Planetary Science
• Atmospheric Science
• Climate Modeling

Background:

• Mars experiences global dust storms (GDS) that significantly alter its atmospheric conditions.
• Previous studies primarily focused on the cooling effects of dust storms due to solar absorption.

Purpose of the Study:

• To investigate the impact of the 2018 Mars Global Dust Storm (GDS) on surface and near-surface air temperatures.
• To analyze the spatial distribution and magnitude of temperature changes across the Martian surface.

Main Methods:

• Assimilation of Mars Climate Sounder (MCS) observations.
• Analysis of surface radiative flux, surface temperature, and air temperature data.
• Comparison with previous dust storm events and simulation results.

Main Results:

• The globally averaged surface temperature showed a warming of 0.9 K, contrary to expected cooling.
• Significant spatial heterogeneity in temperature changes, with localized cooling up to 16 K and warming up to 19 K.
• Net warming occurred in low thermal inertia regions due to enhanced longwave emission and scattering, leading to strong nightside warming that outweighed dayside cooling.
• Reduced surface-air temperature gradients resulted in coupled temperature changes and local dayside air warming.

Conclusions:

• The spatial structure of a GDS is critical in determining its global surface temperature effects.
• Mars's 2018 GDS demonstrated a complex interplay between radiative forcing, thermal inertia, and atmospheric dynamics influencing surface temperatures.
• Findings challenge simplified models of dust storm impacts, highlighting the importance of regional variations.