scholarly journals Large-Eddy Simulations of Dust Devils and Convective Vortices

2017 ◽  
pp. 245-275 ◽  
Author(s):  
Aymeric Spiga ◽  
Erika Barth ◽  
Zhaolin Gu ◽  
Fabian Hoffmann ◽  
Junshi Ito ◽  
...  
Keyword(s):  
Large Eddy Simulations ◽  
Dust Devils ◽  
Large Eddy ◽  
Convective Vortices

scholarly journals Large-Eddy Simulations of Dust Devils and Convective Vortices

2016 ◽  
Vol 203 (1-4) ◽  
pp. 245-275 ◽  
Author(s):  
Aymeric Spiga ◽  
Erika Barth ◽  
Zhaolin Gu ◽  
Fabian Hoffmann ◽  
Junshi Ito ◽  
...  
Keyword(s):  
Large Eddy Simulations ◽  
Dust Devils ◽  
Large Eddy ◽  
Convective Vortices

scholarly journals Vortex Encounter Rates with Fixed Barometer Stations: Comparison with Visual Dust Devil Counts and Large-Eddy Simulations

2014 ◽  
Vol 71 (12) ◽  
pp. 4461-4472 ◽  
Author(s):  
Ralph D. Lorenz
Keyword(s):  
Pressure Drop ◽  
Field Studies ◽  
Large Eddy Simulations ◽  
Encounter Rate ◽  
Dust Devil ◽  
Dust Devils ◽  
Translation Speed ◽  
Pressure Drops ◽  
Large Eddy ◽  
Dust Lifting

Abstract A phenomenological model is developed wherein vortices are introduced at random into a virtual arena with specified distributions of diameter, core pressure drop, longevity, and translation speed, and the pressure history at a fixed station is generated using an analytic model of vortex structure. Only a subset of the vortices present are detected as temporary pressure drops, and the observed peak pressure-drop distribution has a shallower slope than the vortex-core pressure drops. Field studies indicate a detection rate of about two vortex events per day under favorable conditions for a threshold of 0.2 mb (1 mb = 1 hPa): this encounter rate and the observed falloff of events with increasing pressure drop can be reproduced in the model with approximately 300 vortices per square kilometer per day—rather more than the highest visual dust devil counts of approximately 100 devils per square kilometer per day. This difference can be reconciled if dust lifting typically only occurs in the field above a threshold core pressure drop of about 0.3 mb, consistent with observed laboratory pressure thresholds. The vortex population modeled to reproduce field results is concordant with recent high-resolution large-eddy simulations, which produce some thousands of 0.04–0.1-mb vortices per square kilometer per day, suggesting that these accurately reproduce the character of the strongly heated desert boundary layer. The amplitude and duration statistics of observed pressure drops suggest large dust devils may preferentially be associated with low winds.

Daytime and nighttime turbulence on Mars monitored by InSight

2020 ◽  
Author(s):  
Aymeric Spiga ◽  
Naomi Murdoch ◽  
Don Banfield ◽  
Ralph Lorenz ◽  
Claire Newman ◽  
...  
Keyword(s):  
Gravity Waves ◽  
High Frequency ◽  
Seismic Signal ◽  
Atmospheric Science ◽  
Large Eddy Simulations ◽  
Dust Devil ◽  
Large Eddy ◽  
The Many ◽  
Convective Vortices

<p>The InSight instrumentation for atmospheric science combines high frequency, high accuracy and continuity. This makes InSight a mission particularly suitable for studies of the variability in the Planetary Boundary Layer (PBL) of Mars -- all the more since this topic is of direct interest for quake detectability given that turbulence is the main contributor to atmosphere-induced seismic signal. For the strong daytime buoyancy-driven PBL convection, InSight significantly extends the statistics of dust-devil-like convective vortices and turbulent wind gustiness, both of which are of strong interest for aeolian science. For the moderate nighttime shear-induced PBL convection, InSight enables to explore phenomena and variability left unexplored by previous in-situ measurements on Mars. In both daytime and nighttime environments, how the gravity waves and infrasound signals discovered by InSight are being guided within the PBL is also a central topic to InSight's atmospheric investigations, with the tantalizing possibility to identify possible sources for those phenomena. InSight has been operating at the surface of Mars since 18 months, thus the seasonal evolution of the many phenomena occurring in the PBL will be an emphasis of this report. Comparisons with turbulence-resolving modeling such as Large-Eddy Simulations will be also discussed.</p>

scholarly journals Comment on ''Observing desert dust devils with a pressure logger" by Lorenz (2012) – insights on measured pressure fluctuations from large-eddy simulations

2012 ◽  
Vol 1 (2) ◽  
pp. 151-154 ◽  
Author(s):  
A. Spiga
Keyword(s):  
Pressure Fluctuations ◽  
Field Measurements ◽  
Large Eddy Simulations ◽  
Pressure Measurements ◽  
Dust Devils ◽  
Pressure Drops ◽  
Large Eddy ◽  
Measured Pressure ◽  
Term Field

Abstract. Lorenz et al. (2012) proposes to use pressure loggers for long-term field measurements in terrestrial deserts. The dataset obtained through this method features both pressure drops (reminiscent of dust devils) and periodic convective signatures. Here we use large-eddy simulations to provide an explanation for those periodic convective signatures and to argue that pressure measurements in deserts have broader applications than monitoring dust devils.

scholarly journals Comment on "Observing desert dust devils with a pressure logger" by Lorenz (2012)

2012 ◽  
Vol 2 (2) ◽  
pp. 593-601 ◽  
Author(s):  
A. Spiga
Keyword(s):  
Field Measurements ◽  
Large Eddy Simulations ◽  
Pressure Measurements ◽  
Dust Devils ◽  
Pressure Drops ◽  
Desert Dust ◽  
Large Eddy ◽  
Term Field

Abstract. Lorenz (2012) proposes to use pressure loggers for long-term field measurements in terrestrial deserts. The dataset obtained through this method features both pressure drops (reminiscent of dust devils) and periodic convective signatures. Here we use Large-Eddy Simulations to provide an explanation for those periodic convective signatures and to argue that pressure measurements in deserts have broader applications than monitoring dust devils.

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