The First Characterization of Fog Microphysics in the United Arab Emirates, an Arid Region on the Arabian Peninsula

Weston, Michael; Francis, Diana; Temimi, Marouane; Fonseca, Ricardo; Addad, Yacine

doi:10.1029/2021ea002032

Cited by 13 publications

(7 citation statements)

References 63 publications

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“…It can be used to obtain information on N c , LWC, and visibility. This instrument is widely used to measure fog, allowing a consistent comparison of the results with those obtained in other studies (e.g., Weston et al, 2022;Gultepe et al, 2021;Mazoyer et al, 2019;Degefie et al, 2015;Gultepe et al, 2009).…”

Section: Introductionmentioning

confidence: 67%

Applicability of the low-cost optical particle counter OPC-N3 for microphysical measurements of fog

Nurowska

Mohammadi²,

Malinowski³

et al. 2022

Preprint

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Abstract. Low-cost devices for particulate matter measurements are characterized by small dimensions and light weight. This advantage makes them ideal for drone measurements, where those parameters are crucial. However, they also have some issues, like the values of particulate matter from low-cost optical particle counters can be biased by high ambient humidity. In this article, we are evaluating low-cost optical particle counter Alphasense OPC-N3 for measuring the microphysical properties of fog. This study aimed to show that OPC-N3 not only registers aerosols or humidified aerosols but also registers fog droplets. The study was done on the rooftop of Institute of Geophysics, University of Warsaw, Poland, during autumn-winter 2021. To validate the results, the data from OPC-N3 were compared with data obtained from the reference instrument, which was Oxford Laser VisiSize D30. VisiSize D30 is a shadowgraph device able to register photos of individual droplets. Taking into consideration the effective radius of droplets, it is possible to differentiate low-visibility situations between fog conditions (which are not hazardous for people) from haze events, when highly polluted air can cause health risks to people. The compared microphysical proprieties were liquid water content (LWC), number concentration (Nc), effective radius <reff > and statistical moments of radius. The Pearson correlation coefficient for LWC was 0.91, Nc was 0.94, and for <reff > was 0.63. Overall, these results suggest a good compliance between devices. However, the OPC-N3 has to be corrected in reference to professional equipment. To conclude, our study provides the foundation for a new application of the optical particle counter Alphasense OPC-N3 within drones to measure the vertical profiles of the microphysical properties of fog.

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Section: Introductionmentioning

confidence: 67%

Applicability of the low-cost optical particle counter OPC-N3 for microphysical measurements of fog

Nurowska

Mohammadi²,

Malinowski³

et al. 2022

Preprint

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“…This observation is expected, as the SHAMS location is further inland compared to other coastal locations, such as Barakah and Abu Dhabi. Previous studies conducted at Barakah reported the persistent occurrence of strong northwesterly winds for several days when the location is under the influence of favorable synoptic conditions (Abida et al, 2022;Nelli et al, 2022;Weston et al, 2022).…”

Section: Background Weather Conditions During Wise-uae Phase-1mentioning

confidence: 97%

The Wind‐Blown Sand Experiment in the Empty Quarter Desert: Roughness Length and Saltation Characteristics

Nelli,

Francis,

Sow

et al. 2024

Earth and Space Science

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The Empty Quarter Desert, one of Earth's major dust sources, frequently experiences dust storms due to wind erosion. Despite its significance as a primary dust source on a global scale, in‐situ observations from this region had not been reported until very recently. In summer 2022, the WInd‐blown Sand Experiment (WISE) Phase‐1 was initiated in the Empty Quarter Desert of the United Arab Emirates, and continued until 7 February 2023. Utilizing a diverse array of instruments, we measured winds, temperature, humidity, radiation fluxes, saltation, and the physical and optical properties of dust aerosols, atmospheric electric fields, and soil characteristics. A total of 38 distinct sand‐saltation events were recorded from September 2022 to February 2023, with activity peaking between 13:00 and 14:00 local time. Key findings include the identification of dominant wind patterns, and the measurement of the average aerodynamic roughness length (z0) at 0.8 ± 0.6 mm, and the thermal roughness length (zh) at 0.3 ± 0.5 mm—the first estimation of zh for this area. In‐situ observations revealed that dust particle concentrations near the surface increased 1.7‐fold on days with saltation compared to days without it. Moreover, we determined a wind‐speed threshold for initiating saltation at 7.70 m s−1. This comprehensive data set significantly advances our understanding of atmospheric‐soil interactions and sand movement dynamics, providing invaluable insights for ongoing research into desert environments and the global dust cycle.

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“…Fog also developed in the early hours of 17 February (Figure 3 of Weston et al, 2022) but did not last as long, probably because of the rapid changes in the strength of the wind with speeds as high as 3.5 m s −1 and a prevailing onshore (north to northeast) direction. The microphysics of the fog events that occurred during this field campaign are reported in Weston et al (2022).…”

Section: Fog Event On 15-16 February 2021mentioning

confidence: 99%

Characterization of the atmospheric circulation near the Empty Quarter Desert during major weather events

Nelli

Francis²,

Fonseca³

et al. 2022

Front. Environ. Sci.

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In this study, we characterize the meteorological conditions and planetary boundary layer dynamics in western United Arab Emirates based on 2012–2020 in-situ measurements. This multi-year analysis is then complemented by an intensive field-campaign in winter 2021 from which we address the main patterns of the atmospheric circulation and the boundary layer structure during typical weather events identified in the long-term analysis. We found that, 10-m and 60-m wind speeds are generally below 5 m s−1 and 8 m s−1, respectively, blowing predominantly from a northerly direction. They peak in intensity at around 12–18 Local Time (LT) and 02–09 LT in association with the sea-breeze and the downward mixing of momentum from the nighttime low-level jet, respectively. The wind is stronger in the cold season, varying mostly in response to mid-latitude baroclinic systems, while the proximity of the site to the core of the Arabian Heat Low leads to more quiescent conditions in the summer. Radiation fog is a regular occurrence mostly from December to February owing to the colder nights and weaker wind speeds, with a peak fog occurrence around local sunrise. Sea fog, which develops when the hotter desert air is transported over the cooler Arabian Gulf waters, is advected to the site in the summer. Deep and very deep convective clouds are more common in March-April in association with organized convective systems, with generally reduced cloud cover from May to October. The region of interest exhibits a monthly-mean aerosol optical depth ranging from ∼0.3 in December-January to ∼1.2 in July due to its increased exposure to dust storms in the summer season. Dust activity is also found to peak during winter and spring associated with the intrusion of cold fronts from mid-latitudes.

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The First Characterization of Fog Microphysics in the United Arab Emirates, an Arid Region on the Arabian Peninsula

Cited by 13 publications

References 63 publications

Applicability of the low-cost optical particle counter OPC-N3 for microphysical measurements of fog

Applicability of the low-cost optical particle counter OPC-N3 for microphysical measurements of fog

The Wind‐Blown Sand Experiment in the Empty Quarter Desert: Roughness Length and Saltation Characteristics

Characterization of the atmospheric circulation near the Empty Quarter Desert during major weather events

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