“An Entrainment Paradox: How Hysteretic Saltation and Secondary Transport Augment Atmospheric Uptake of Aeolian Source Materials”

Abstract

Introduction BackgroundAerodynamically driven emission of dust is important for weather, climate, the hydrologic cycle, ecosystems, etc. On Earth, dust storms occur locally in arid and semiarid parts of the world and are responsible for injecting aerosols into the atmosphere that are eventually deposited in the oceans and elsewhere on the planet (Goudie, 1978). Iron-containing soil dust that is deposited in the ocean via dust storms can affect the climate and ocean biochemistry and hence can affect aquatic lives and nutrient distribution in the ocean (Jickells et al., 2005). Dust deposition can also affect ocean productivity (Martin et al., 1991) and CO 2 concentration (Broecker & Henderson, 1998;Martin, 1990). Suspended particles in the air due to dust storms can have a negative impact on human health (Griffin & Kellogg, 2004). Aerosols suspended in the air can travel thousands of kilometers away from the origin of the dust storm, affecting the weather in faraway places (Prospero, 2001;Tegen et al., 1996). Although dust storms occur locally on Earth, they can have global effects on climate and weather. Hence, it is extremely important to understand the origin, evolution, and entrainment mechanisms of dust storms. On Mars, dust affects performance of scientific instruments mounted upon campaigning rovers.

On the Influence of Thermal Stratification on Emitted Dust Flux

“…We suspect that the size of aeolian streamers might evolve with thermal stratification as the character of large-scale motions, provided that saltation is still maintained. This difference of turbulent motions involved in saltation and dust emission represents the entrainment paradox discussed by Rana et al (2021), where the strongest large-scale DUPONT 10.1029/2022JD037364…”

“…This difference of turbulent motions involved in saltation and dust emission represents the entrainment paradox discussed by Rana et al. (2021), where the strongest large‐scale downward motions initiate saltation while smaller secondary upward motions entrain dust further above in the atmosphere.…”

Dust Settling From Turbulent Layers in the Free Troposphere: Implications for the Saharan Air Layer

“…The long‐lasting, global dust storms on Mars are another example of a similar problem that is particularly relevant at present due to the challenges that it poses to the robotic exploration of that planet. In this case, though, the bottom of the flow is a solid boundary, and physical parameters (such as gravity and density) can have very different values as compared to terrestrial flows (Rana et al., 2021). Hence, in this text, phrases like “dust in the SAL” will often be used in situations where ideas also apply more generally to particles settling in turbulent flows, and can potentially be extended to other geophysical problems.…”