Quantifying Mechanisms of Aeolian Dust Emission: Field Measurements at Etosha Pan, Namibia

Wiggs, Giles F.S.; Baddock, Matthew C.; Thomas, David S.G.; Washington, Richard; Holdt, Johanna von; Engelstaedter, Sebastian; Bryant, Robert G.; Eckardt, Frank D.; Holdt, Johannah R.C. von; Kötting, Shayne

doi:10.1029/2022jf006675

Cited by 7 publications

(7 citation statements)

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“…As observed at low latitudes (e.g. Marticorena et al, 2017; Wiggs et al, 2022), dust transport during the measurement period is dominated by a single high magnitude, low frequency event (Event 7) that accounted for 45% of total event flux.…”

Section: Discussionmentioning

confidence: 63%

“…Cosentino et al, 2020; Mockford et al, 2018; Thorsteinsson et al, 2011) and as an indicator of all dust emissions (and wind erosion activity) in the area rather than only events of prescribed magnitudes. Using the method of Wiggs et al (2022), for each dust event, an indicative event flux was derived from the co‐located measurements of dust concentration and wind speed at 2.5‐m height.…”

Section: Methodsmentioning

confidence: 99%

“…It may also be locally derived where vegetation is disturbed enabling the erosion of loessic soils (Heindel et al, 2015). Marticorena et al, 2017;Wiggs et al, 2022), dust transport during the measurement period is dominated by a single high magnitude, low frequency event (Event 7) that accounted for 45% of total event flux.…”

Section: Meteorological Conditions and Dust Concentrationmentioning

confidence: 99%

“…The diurnal dust cycle can also vary seasonally due to changes in ground surface conditions (moisture, snow, vegetation) and local wind conditions (Orgill & Sehmel, 1976). The daily cycle results in pulses of dust emission to the atmosphere, and the relative timing of these versus surface or satellite observations has implications for the estimation of total dust emission in a region (Todd et al, 2007;Wiggs et al, 2022). Some studies from the high latitudes suggest similar diurnal patterns of dust to those in the low latitudes (e.g.…”

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confidence: 99%

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Diurnal and seasonal source‐proximal dust concentrations in complex terrain, West Greenland

Bullard

Prater

Baddock

et al. 2023

Earth Surf Processes Landf

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Diurnal and seasonal cycles of aeolian activity are well‐constrained for low latitude dust source regions and provide valuable insights into relationships between dust emissions and environmental drivers. Such cycles have received little systematic attention in high latitude dust source areas (≥50°N and ≥40°S), and understanding them will aid the modelling of atmospheric dust over different timescales. This paper examines the timing and drivers of atmospheric dust concentration close to source at ice‐free locations c. 6 km and c. 37 km from the Greenland Ice Sheet margin. Dust concentration, and associated environmental drivers including wind speed and velocity, air temperature and humidity, was measured from April–October 2018 and April–August 2019. Measured dust concentrations were a similar order of magnitude to source‐proximal values measured globally and varied from 0 to ≥1000 μg m−3. Diurnal cycles in the environmental drivers of dust emission were similar to those observed in low latitudes, but unlike in the low latitudes, there was no clear diurnal pattern of dust concentration. Only 3 out of 17 recorded dust events showed a significant positive relationship between wind speed and dust concentration, and factors such as wind direction, humidity and sediment availability are the over‐riding controls on dust activity at the event and seasonal scales. Whereas 7 dust events are attributed to down‐valley katabatic winds, 10 events were associated with a westerly sea breeze blowing up‐valley towards the ice sheet and high atmospheric moisture content. If deposited on the ice, this dust will alter ice albedo both directly and indirectly, (e.g. through the promotion of algal blooms) affecting cryospheric melt rates. Our results demonstrate an intricate relationship between first‐order controls and dust concentration that raises challenges for modelling the uplift and subsequent dust transport from high latitude sources, especially the appropriateness of assumptions based on emissions behaviour at low latitudes.

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Section: Discussionmentioning

confidence: 63%

Section: Methodsmentioning

confidence: 99%

Section: Meteorological Conditions and Dust Concentrationmentioning

confidence: 99%

mentioning

confidence: 99%

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Diurnal and seasonal source‐proximal dust concentrations in complex terrain, West Greenland

Bullard

Prater

Baddock

et al. 2023

Earth Surf Processes Landf

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“…These pressures are rather lower than previously assumed Mars values and much lower—by a factor of several—than those found at Earth (Table 1) for example, in field campaigns (Wiggs et al., 2022) or used to reconcile pressure drop statistics with observed visible dust devils (Lorenz, 2014). This large difference makes quibbles about altitude of wind measurement somewhat negligible.…”

Section: Figurementioning

confidence: 54%

Gentle Perseverance Lifts the Veil on Martian Dust

Lorenz

2023

JGR Planets

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Observations with sensitive photodiode detectors on the Perseverance rover (Hueso et al., 2023, https://doi.org/10.1029/2022JE007516; Vicente‐Retortillo et al., 2023, https://doi.org/10.1029/2022je007672) to detect dust devils and track formation, and movies of the Ingenuity helicopter's downwash impingement on the Martian surface (Lemmon et al., 2022a, https://doi.org/10.1029/2022je007605; Lemmon et al., 2022b, https://doi.org/10.1029/2022gl100126), together with in‐situ meteorological data, give new insights into the important problem of dust‐lifting on Mars, a phenomenon which influenced the lifetime of recent rovers and landers. These results, together with new low‐gravity wind tunnel experiments on parabolic flights and interpretation of the large blast pattern from lander retrorockets, indicate that particle motion and visible darkening on Mars can result from aerodynamic pressures of only 1–5 Pa, considerably less than previously thought.

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Satellite observations of Arctic blowing dust events >82°N

Baddock,

Hall,

Rideout

et al. 2024

Weather

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This study reports satellite evidence for the most northerly blown dust activity yet observed on Earth. A systematic inspection of high‐resolution satellite imagery identified active dust events and their sources >82°N in Peary Land, Greenland. In the absence of any local weather measurements, for all observed dust activity a focus period in April 2020 with multiple dust plumes, reanalysis climate data found the majority of dust events to be associated with wind speeds exceeding a typical threshold value for blowing sand and dust uplift. Wind direction variability points to dust‐raising by cold airflow down‐valley winds, likely from nearby ice masses.

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Quantifying Mechanisms of Aeolian Dust Emission: Field Measurements at Etosha Pan, Namibia

Abstract: Windblown dust is a major global export from the world's deserts and plays a critical role in the Earth's land-atmosphere-ocean-biosphere system (Shao et al., 2011). It has been shown to have a crucial influence on the radiation balance and climate modulation (

Cited by 7 publications

References 111 publications

Diurnal and seasonal source‐proximal dust concentrations in complex terrain, West Greenland

Diurnal and seasonal source‐proximal dust concentrations in complex terrain, West Greenland

Gentle Perseverance Lifts the Veil on Martian Dust

Satellite observations of Arctic blowing dust events >82°N

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