Some features of effective radius and variance of dust particles in the numerical simulation of dust climate on Mars

TL;DR

This paper develops analytical expressions for variable effective radius and variance of dust particles in Mars climate models, showing that dust size variability significantly impacts atmospheric radiation and thermal simulations.

Contribution

It introduces a new method to incorporate variable dust size parameters into numerical simulations of Mars's atmosphere, improving realism over fixed-size assumptions.

Findings

Dust size parameters vary seasonally and spatially.

Variable dust size affects atmospheric radiation and thermal fields.

Results align with observational and previous modeling studies.

Abstract

Airborne dust is an important constituent in the Martian atmosphere because of its radiative interaction with the atmospheric circulation, and dust size is one crucial factor in determining this effect. In numerical modeling of the dust processes, description of the dust size is usually dependent on the choice of a particular size distribution function, or with fixed values of effective radius (ER) and effective variance (EV) though they are variable in reality. In this work, analytical expressions have been derived to specify ER and EV for N-bin dust schemes based on the model calculated dust mixing ratio. Numerical simulations based on this approach thus consider the effects of variable ER on the atmospheric radiation and their interaction. The results have revealed some interesting features of the dust distribution parameters such as the seasonal and spatial variation of ER and EV, which are generally consistent with some previous observational and modeling studies. Compared with the usual approach of using fixed ER, simulation results with the present approach suggest that the variability of ER can have significant effect on the simulated thermal field of the Martian atmosphere.