The properties of Martian aerosols are an integral part of the planetary climatology. Global dust storms (GDS) significantly alter spatial and vertical distributions of dust and water ice aerosols and their microphysical properties. We explored the 2018/Martian year 34 GDS with the Atmospheric Chemistry Suite instrument onboard the ESA‐Roscosmos Trace Gas Orbiter mission. Solar occultation observations of thermal infrared and near infrared channels in the 0.7–6 μm spectral range with >10³ signal‐to‐noise ratio are used to constrain the vertical dependence and the temporal evolution of the particle properties of water ice and dust (effective radius, effective variance, number density, and mass loading) before the 2018 GDS and during its onset and decay phases. In most of the observations, the particle size of dust and water ice decreases with altitude. The effective radius of dust and water ice particles ranges in 0.1−3.5 μm and 0.1–5.5 μm, respectively. The largest aerosol particles (> 2.5 μm for dust and > 3.5 μm for water ice) are present below 10 km before the onset and during the GDS decay phase. During the peak of the GDS, dust reached altitudes of 85 km; the most frequently observed effective radius is 1–2 μm with 0.1–1 cm⁻³ number density and 0.1 effective variance. Detached layers of water ice composed of 0.1–1 μm particles are systematically observed at 50–100 km during this period. Below, at 0–50 km, we see the dust mixed with the main water ice layer comprising 1–4 μm particles.

中文翻译：

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根据大气化学套件推断，2018年全球沙尘暴期间火星大气中水冰和尘埃颗粒的特性

火星气溶胶的特性是行星气候学的组成部分。全球沙尘暴（GDS）极大地改变了尘埃和水冰气溶胶的空间和垂直分布及其微物理特性。我们通过ESA‐Roscosmos微量气体轨道飞行器飞行任务的大气化学套件仪器探索了2018 /火星年34 GDS。在0.7–6μm光谱范围内，> 10 ³的热红外和近红外通道的太阳掩星观测信噪比用于限制2018年GDS之前及其爆发和衰减期间水冰和尘埃颗粒特性（有效半径，有效方差，数量密度和质量负荷）的垂直依赖性和时间演变阶段。在大多数观察中，尘埃和水冰的粒径随高度的增加而减小。尘埃和水冰颗粒的有效半径分别为0.1-3.5μm和0.1-5.5μm。最大的气溶胶颗粒（粉尘大于2.5微米，水冰大于3.5微米）在发病前和GDS衰变阶段低于10 km。在GDS高峰期，灰尘达到了85 km的高度；最经常观察到的有效半径是1–2μm，0.1–1 cm ^-3数密度和0.1有效方差。在此期间，有系统地在50-100 km处观察到由0.1–1μm颗粒组成的水冰分离层。在0-50 km下方，我们看到灰尘与包含1-4μm颗粒的主要水冰层混合。