Modeling the Hydrological Cycle in the Atmosphere of Mars: Influence of a Bimodal Size Distribution of Aerosol Nucleation Particles

Abstract

We present a new implementation of the hydrological cycle scheme into a general circulation model of the Martian atmosphere. The model includes a semi‐Lagrangian transport scheme for water vapor and ice and accounts for microphysics of phase transitions between them. The hydrological scheme includes processes of saturation, nucleation, particle growth, sublimation, and sedimentation under the assumption of a variable size distribution. The scheme has been implemented into the Max Planck Institute Martian general circulation model and tested assuming monomodal and bimodal lognormal distributions of ice condensation nuclei. We present a comparison of the simulated annual variations, horizontal and vertical distributions of water vapor, and ice clouds with the available observations from instruments on board Mars orbiters. The accounting for bimodality of aerosol particle distribution improves the simulations of the annual hydrological cycle, including predicted ice clouds mass, opacity, number density, and particle radii. The increased number density and lower nucleation rates bring the simulated cloud opacities closer to observations. Simulations show a weak effect of the excess of small aerosol particles on the simulated water vapor distributions.

Martian Dust Storms and Gravity Waves: Disentangling Water Transport to the Upper Atmosphere

“…The water cycle of the model includes a semi‐Lagrangian transport of water vapor and ice (Shaposhnikov et al., 2016) and accounts for the microphysics of conversions between vapor and ice (Shaposhnikov et al., 2018). Condensation occurs on cloud condensation nuclei, whose sizes are represented by four characteristic bins.…”

Seasonal Water “Pump” in the Atmosphere of Mars: Vertical Transport to the Thermosphere

“…The size of ice particles determines their microphysical properties and the sedimentation rate. The CCN number density in each bin is calculated from the bimodal log‐normal dust distribution (Fedorova et al, ), as described in the paper of Shaposhnikov et al (, section 2.2).…”

Properties of Water Ice and Dust Particles in the Atmosphere of Mars During the 2018 Global Dust Storm as Inferred From the Atmospheric Chemistry Suite

“…2001). Information on the aerosols physical properties is needed for a better understanding and modeling of Martian climate (Guzewich et al., 2013; Madeleine et al., 2012; Navarro et al., 2014; Shaposhnikov et al., 2018).…”