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Icelandic topsoil sediments, as confirmed by numerous scientific studies, represent the largest and the most important European source of mineral dust. Strong winds, connected with the intensive cyclonic circulation in the North Atlantic, induce intense emissions of mineral dust from local sources all year and carry away these fine aerosol particle...
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... Simulations of winds channeled through a narrow river valley in Idaho underestimated maximum "wind strength, due to terrain smoothing and underestimation of the sea level pressure gradient," even with a model grid spacing of 1.3 km (Wagenbrenner et al., 2018). The first fully dynamic high-resolution (0.05°, or ∼3.5 km) numerical atmosphericdust modeling system capable of simulating Icelandic dust transport, suggested that 10 km model resolution would be too coarse to resolve highly emissive areas (Cvetkovic et al., 2022). The spatial resolution of 40-160 km, typical of most dust models, is thus too coarse, by more than an order of magnitude, to accurately simulate the dust-generating winds emanating from the narrow mountain river valley dust source areas of southern Alaska. ...
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The growth of phytoplankton, the base of the marine food web, is known to be limited by availability of the micronutrient iron in the Gulf of Alaska. We evaluated the importance of glacial dust in this region as a source of iron, and other trace metals, by using concentrations of the rare earth elements and thorium in particles as tracers of their geographic origin. We analyzed for these elements in glacial dust samples from the Copper River valley (Alaska), the largest source of glacier‐derived dust. Together with previously published concentrations for dust from Asia and volcanic material, we estimated the inputs of each source material to the sediments of the Gulf of Alaska. This information, together with published sediment mass accumulation rates, suggests an important contribution of Alaskan glacial dust and associated iron, to surface waters of the Gulf of Alaska, at least 1,000 km from the source. Dust models fail to accurately simulate this dust transport because their coarse spatial resolution substantially underestimates wind speeds. Glacial dust fluxes may have been important sources of iron in the geologic past (e.g., the Last Glacial Maximum) from New Zealand and South America, when there was more extensive glacial coverage.
... Dust is an important factor in atmospheric pollution due to both natural sources and anthropogenic factors [9]. The latter include construction and road works. ...
We investigated the operating conditions of excavator equipment, leading to unsteady dynamics of dust far from the pollution source. Wind transport of dust takes into account the non-uniform vertical wind profile. Diffusion movement is also determined by the inhomogeneous coefficient of turbulent diffusion with a nonmonotonic dependence on height. The Earth’s surface is given by a digital elevation model, which allows calculations for a specific area with complex topography. Vertical inhomogeneities of wind and turbulence significantly change the nature of the spatial distributions of dust particles. Our approach makes it possible to determine changes in the disperse composition of particles with distance from the dust source.
... In the rough mixing regime, the near-surface turbulence increases, and the VSL depth decreases. Under fully developed turbulent conditions (very rough regime), emission reaches its maximum, and VSL depth vanishes (Cvetkovic et al., 2022). ...
When exposed to convective thunderstorm conditions, pollen grains can rupture and release large numbers of allergenic sub-pollen particles (SPPs). These sub-pollen particles easily enter deep into human lungs, causing an asthmatic response named thunderstorm asthma (TA). Up to now, efforts to numerically predict the airborne SPP process and to forecast the occurrence of TAs are unsatisfactory. To overcome this problem, we have developed a physically-based pollen model (DREAM-POLL) with parameterized formation of airborne SPPs caused by convective atmospheric conditions. We ran the model over the Southern Australian grass fields for 2010 and 2016 pollen seasons when four largest decadal TA epidemics happened in Melbourne. One of these TA events (in November 2016) was the worldwide most extreme one which resulted to nine deaths and hundreds of hospital patient presentations. By executing the model on a day-by-day basis in a hindcast real-time mode we predicted SPP peaks exclusively only when the four major TA outbreaks happened, thus achieving a high forecasting success rate. The proposed modelling system can be easily implemented for other geographical domains and for different pollen types.
Characterising the physico-chemical properties of dust-emitting sediments in arid regions is fundamental to understanding the effects of dust on climate and ecosystems. However, knowledge regarding high-latitude dust (HLD) remains limited. This study focuses on analysing the particle size distribution (PSD), mineralogy, cohesion, iron (Fe) mode of occurrence, and visible–near infrared (VNIR) reflectance spectra of dust-emitting sediments from dust hotspots in Iceland (HLD region). Extensive analysis was conducted on samples of top sediments, sediments, and aeolian ripples collected from seven dust sources, with particular emphasis on the Jökulsá basin, encompassing the desert of Dyngjunsandur. Both fully and minimally dispersed PSDs and their respective mass median particle diameters revealed remarkable similarities (56 ± 69 and 55 ± 62 µm, respectively). Mineralogical analyses indicated the prevalence of amorphous phases (68 ± 26 %), feldspars (17 ± 13 %), and pyroxenes (9.3 ± 7.2 %), consistent with thorough analyses of VNIR reflectance spectra. The Fe content reached 9.5 ± 0.40 wt %, predominantly within silicate structures (80 ± 6.3 %), complemented by magnetite (16 ± 5.5 %), hematite/goethite (4.5 ± 2.7 %), and readily exchangeable Fe ions or Fe nano-oxides (1.6 ± 0.63 %). Icelandic top sediments exhibited coarser PSDs compared to the high dust-emitting crusts from mid-latitude arid regions, distinctive mineralogy, and a 3-fold bulk Fe content, with a significant presence of magnetite. The congruence between fully and minimally dispersed PSDs underscores reduced particle aggregation and cohesion of Icelandic top sediments, suggesting that aerodynamic entrainment of dust could also play a role upon emission in this region, alongside saltation bombardment. The extensive analysis in Dyngjusandur enabled the development of a conceptual model to encapsulate Iceland's rapidly evolving high dust-emitting environments.
Characterizing physico-chemical properties of dust-emitting sediments in arid regions is fundamental to understand the effect of dust on climate and ecosystems. For high-latitude dust (HLD), this knowledge is scarce. This study focuses on the particle size distribution (PSD), mineralogy, cohesion, iron (Fe) mode of occurrence and Visible Near Infra-Red (VNIR) reflectance spectra of dust-emitting sediments from dust-hotspots in Iceland (HLD region). Extensive analysis was conducted on top sediments collected from seven dust-sources and an intensive at Jokulsá basin including top sediments, sediments and aeolian ripples. Fully and minimally dispersed PSDs evidenced remarkable similarities with an average median diameter of 56±69 and 55±62 µm. Mineralogical analyses showed the prevalence of amorphous phases (68±26 %), feldspars (17±13 %), and pyroxenes (9.3±7.2 %), aligned with the reflectance spectra. Fe content reached 9.5±0.40 wt %, mainly in silicate structures (80±6.3 %), complemented by magnetite (16±5.5 %), hematite/goethite (4.5±2.7 %), and readily exchangeable Fe-ions or Fe nano-oxides (1.6±0.63 %). Icelandic top sediments have coarser PSD compared to the high dust-emitting crusts from mid-latitude arid regions, distinctive mineralogy, and threefold bulk Fe content, with a large presence of magnetite. The congruence between fully and minimally dispersed PSDs underscores a reduced particle aggregation and cohesion of Icelandic top sediments, suggesting that aerodynamic entrainment of dust may also play a role upon emission in this region, aside of saltation bombardment. The analysis of an extensive sampling in Dyngjusandur allowed this study to present a conceptual model to encapsulate Iceland's rapidly evolving high dust-emitting environments.
Dust particles from high latitudes have a potentially large local, regional, and global significance to climate and the environment as short-lived climate forcers, air pollutants, and nutrient sources. Identifying the locations of local dust sources and their emission, transport, and deposition processes is important for understanding the multiple impacts of high-latitude dust (HLD) on the Earth's systems. Here, we identify, describe, and quantify the source intensity (SI) values, which show the potential of soil surfaces for dust emission scaled to values 0 to 1 concerning globally best productive sources, using the Global Sand and Dust Storms Source Base Map (G-SDS-SBM). This includes 64 HLD sources in our collection for the northern (Alaska, Canada, Denmark, Greenland, Iceland, Svalbard, Sweden, and Russia) and southern (Antarctica and Patagonia) high latitudes. Activity from most of these HLD sources shows seasonal character. It is estimated that high-latitude land areas with higher (SI ≥0.5), very high (SI ≥0.7), and the highest potential (SI ≥0.9) for dust emission cover >1 670 000 km2, >560 000 km2, and >240 000 km2, respectively. In the Arctic HLD region (≥60∘ N), land area with SI ≥0.5 is 5.5 % (1 035 059 km2), area with SI ≥0.7 is 2.3 % (440 804 km2), and area with SI ≥0.9 is 1.1 % (208 701 km2). Minimum SI values in the northern HLD region are about 3 orders of magnitude smaller, indicating that the dust sources of this region greatly depend on weather conditions. Our spatial dust source distribution analysis modeling results showed evidence supporting a northern HLD belt, defined as the area north of 50∘ N, with a “transitional HLD-source area” extending at latitudes 50–58∘ N in Eurasia and 50–55∘ N in Canada and a “cold HLD-source area” including areas north of 60∘ N in Eurasia and north of 58∘ N in Canada, with currently “no dust source” area between the HLD and low-latitude dust (LLD) dust belt, except for British Columbia. Using the global atmospheric transport model SILAM, we estimated that 1.0 % of the global dust emission originated from the high-latitude regions. About 57 % of the dust deposition in snow- and ice-covered Arctic regions was from HLD sources. In the southern HLD region, soil surface conditions are favorable for dust emission during the whole year. Climate change can cause a decrease in the duration of snow cover, retreat of glaciers, and an increase in drought, heatwave intensity, and frequency, leading to the increasing frequency of topsoil conditions favorable for dust emission, which increases the probability of dust storms. Our study provides a step forward to improve the representation of HLD in models and to monitor, quantify, and assess the environmental and climate significance of HLD.
