Impact of the coagulation of dust particles on Mars during the 2018 global dust storm

Coagulation of particles occurs when two collide and stick together. In the Martian atmosphere, dust coagulation would increase effective particle size, as small accrete to larger particles. Murphy et al. (1990) showed that Brownian in atmosphere was not significant, due low mixing ratios, while Montmessin (2002) Fedorova (2014) it mostly involves radii smaller than 0.1 um. However, effects have never been explored 3D, during a global storm, i.e. presence numbers Here we revisit this issue by using NASA Ames Mars Global Climate Model (MGCM) investigate temporal spatial changes sizes 2018 storm overall impact these processes on Mars' climate. Our parameterization for includes effect motion, diffusion enhancement, gravitational collection. We show motion enhancement dominate The is significant with rates increased factor 10 compared non-storm conditions. radius can be 2 coagulation, leading 20K colder above 30 km altitude. Overall, our improves representation decay phase relative observations. process remains outside period if large submicron-sized are involved. It may possible, GCMs, lift amounts from surface without excess buildup thus improving agreement some observations diverging observed column opacities.