Martian interactive dust and water cycle GCM simulations as compared with TGO/NOMAD and MCS observations
Authors: Senel Cem Berk , Temel Orkun , Karatekin Ozgur 
Published: February 2023

The dust cycle is the key driver of the Martian climate, therefore capturing the time-evolving dust distribution correctly is vital for simulating a realistic climate. The proper modeling of the dust cycle is closely coupled with water cycle dynamics, as both affect the radiative state of the atmosphere as well as general circulations. A better understanding of the dust-water cycle feedback is key to advancing our knowledge of the Martian climate system, such as from polar cap evolution towards the dust storm-water escape interaction and the formation of elongated water ice clouds in the wake of a volcano. Recently, we presented decadal GCM simulations of the convective boundary layer until Mars Year 34, unraveling the feedback between Martian turbulence and dust during major storms. Those GCM simulations were carried out by developing an in-house dust transport model [1] constrained by column dust climatology observations [2]. Our model was validated by in-situ observations of NASA&#8217;s MSL rover and orbiter observations from Mars Climate Sounder (MCS) observations. Here, by coupling the fully-interactive water cycle model [3] with our semi-interactive dust transport model [1], we present new dust and water cycle GCM simulations within the ROB version of MarsWRF. We performed a year-long GCM simulation in Mars Year 34, in which the red planet experienced a global dust storm (GDS) that began shortly after the southern summer solstice lasting more than 100 sols. We compared model results with recent spacecraft observations, comprising (i) MCS observations onboard the Mars Reconnaissance Orbiter (MRO) and (ii) Nadir and Occultation for Mars Discovery (NOMAD) onboard the Trace Gas Orbiter (TGO) observations. Recently, from the latter observations, Liuzzi et al. (2020) [4] presented vertical distributions of water ice and dust, besides the large variabilities of water ice clouds within the perihelion season in MY 34. Furthermore, Vandaele et al. (2019) [5] reported rapid alterations in water vapor vertical distributions as driven by Martian dust storms. Here, we simulate vertical distributions of the dust, water ice and vapor on Mars, investigating the responses to the major dust storm events.[1] Senel, C. B., Temel, O., Lee, C., Newman, C. E., Mischna, M. A., ... & Karatekin, O. (2021). Interannual, Seasonal and Regional Variations in the Martian Convective Boundary Layer Derived From GCM Simulations With a Semi&#8208;Interactive Dust Transport Model. JGR: Planets, 126(10), e2021JE006965.[2] Montabone, L., et al. (2020). Martian year 34 column dust climatology from Mars climate sounder observations: Reconstructed maps and model simulations. JGR: Planets, 125(8), e2019JE006111.[3] Lee, C., Richardson, M. I., Newman, C. E., & Mischna, M. A. (2018). The sensitivity of solsticial pauses to atmospheric ice and dust in the MarsWRF General Circulation Model. Icarus, 311, 23-34.[4] Liuzzi, G., et al. (2020). Strong variability of Martian water ice clouds during dust storms revealed from ExoMars Trace Gas Orbiter/NOMAD. Journal of Geophysical Research: Planets, 125(4), e2019JE006250.[5] Vandaele, A. C., et al. (2019). Martian dust storm impact on atmospheric H2O and D/H observed by ExoMars Trace Gas Orbiter. Nature, 568(7753), 521-525.