Sand Drift Research Articles

Numerical Insights Into Gobi Wind‐Blown Sand: Deriving a Saltation Flux Scheme

AbstractDust emissions from land‐air interaction in arid and semi‐arid regions are crucial for predicting the global dust cycle. However, a comprehensive understanding of the complex physical mechanisms contributing to dust emissions from Gobi surfaces remains elusive. The expansive Gobi Desert, spanning northern China and Mongolia, significantly intensifies sandstorms in East Asia. Although researchers use models to study global dust transport, current models primarily depend on the aerodynamic roughness of the Gobi Desert. They often overlook the particle‐bed collision processes unique to the Gobi bed surface, which differ significantly from those of desert surfaces, thus compromising the accuracy of global dust cycle simulations. In this article, we establish a numerical model for drift sand in the Gobi based on existing theoretical and experimental studies. The model accurately simulates the wind‐blown sand in the Gobi and been used to investigate the saltation structure of sand transport. Simulations reveal an exponential decay of mass concentration with height, with an average attenuation rate of 0.00385 in the Gobi compared to 0.00806 in sandy deserts. The horizontal velocity of saltating particles increases with height following a power law. Through quantitative analysis of this structure, we present a saltation flux formula suitable for the Gobi.

Blown sand environment characteristics and bridge sand hazard mechanisms of expressways in the South Tibet Valley.

South Tibet expressways are built in the Yalu Tsangpo valley along the route to high-altitude and cold-temperature valleys, which are the main environmental characteristics of the region. Given that the blown sand environment and its potential harm are unclear, targeted prevention and control are not conducive, but its absence would result in severe wind-sand hazards on these expressways. In this research, the blown sand environment of the South Tibet Valley and the mechanism of sand damage to expressway bridges were studied via field observations, wind tunnel experiments and numerical simulations. The sand-moving wind is mainly west wind. The sand-moving wind frequency, sand drift potential, and maximum possible sand transport quantity are high in winter and spring (November-April) and low in summer and autumn (May-October). The sand drift direction is in the east direction. Expressway bridges have a considerable impact on the near-surface blown sand environment, forming a zone for increasing the wind speed between the top of the slope shoulder of the windward side of the bridge to the center of the bridge abutment, forming a zone for weakening the wind speed between the - 3H distances of the upwind direction to the bottom of the slope middle of the windward side of the bridge, further forming a zone for weakening the wind speed centered in the slope shoulder of the leeward side of the bridge. The wind speed within a distance of 40H downwind direction of the bridge generally did not recover. The wind-sand flow is partially blocked when it passes through the bridge and accumulates near the bridge, which cause harm. The impact of the bridge on the blown sand environment in the downwind is greater than that in the upwind. The results of this study can provide a reference for preventing and controlling wind-sand hazards on South Tibet expressways.

Characteristics of Sand-Driving Wind Regime and Sand Drift Potential in Sandy Areas on Both Sides of Longyangxia Reservoir in China

This study focuses on the desertification areas of Talatan and Mugetan, located on both sides of the Longyangxia Reservoir in Qinghai Province, China. These areas pose serious threats to the safety of the reservoir due to frequent wind-sand activities. The research aims to provide a scientific basis for effective sand control by deeply analyzing the dynamic change of wind.The wind speed and direction data from Shazhuyu and Guinan meteorological stations in Qinghai Province, China were used to calculate the numerical and directional characteristics of sand-driving wind and sand drift potential.The results indicate that: (1) The number of sand-driving wind at Talatan is about 7 times that at Mugetan, and the maximum and average wind speeds are about 7 m/s larger than those at Mugetan. At Talatan, the primary sand-driving wind direction is exclusively West Northwest (WNW). Conversely, at Mugetan, the sand-driving wind direction remains westward in spring, autumn, and winter, shifting eastward solely in summer. (2) The annual sand drift potential of Talatan and Mugetan is less than 200VU, two sandy areas are both in low wind energy environments; (3) The major causes of the significant differences in sand-driving wind regimes between the Talatan and Mugetan are topography, precipitation, wind direction stability.These conclusions offer valuable insights for developing targeted sand control strategies, thereby mitigating the potential hazards posed by wind-sand activities to the Longyangxia Reservoir and its surrounding ecosystems.

Analytical Solution for the Steady Seepage Field of a Foundation Pit in an Anisotropic Layer

The soil piping and drift sand phenomenon is one of the catastrophic failure forms in foundation pit excavations in coastal buildings. Presently, there is a deficiency in the theoretical research regarding the seepage fields around foundation pits, primarily due to the complexity of theoretical solutions given the difficulty in accurately describing the distribution of the groundwater’s hydraulic head in a seepage field. This study proposes an explicit analytical solution for the steady-state seepage field surrounding a foundation pit under anisotropic conditions. A numerical model, constructed with FLAC3D 7.0 software, was utilized to validate the solution presented in this study. The effects of the foundation pit’s width, the distance between the retaining wall and the impervious layer, and anisotropic seepage conditions on the total head are studied through parameter research. The study shows that the flow behavior of a foundation pit is sensitive to parameters such as the anisotropy of the soil layer and the width of the foundation pit. Further, the study also analyzes the influence of the above parameters on the exit gradient and proposes a simplified algorithm for the exit hydraulic gradient at the base of a foundation pit, which can control the error within 5%. This method makes a certain contribution to improving seepage calculations for foundation pits and is applicable to the seepage problem of anisotropic soil layers.

Ventifacts and wind deflation surfaces in context with glaciofluvial sediment successions in southern Sweden – Their age and implication for glacial history

Recent suggestions propose that the glacial landscape in southern Sweden is primarily a relict from the Saalian glaciation (>130 ka). The arguments for this standpoint are the assertion that the majority of glaciofluvial deposits in this region are till-covered, and that wind-abraded clasts are observed at the contact between glaciofluvial sediments and till at numerous locations. Furthermore, it has been posited that this wind abrasion occurred during periglacial conditions during the Early Weichselian, preceding the Last Glacial Maximum (LGM). If this hypothesis holds true, it would necessitate a significant shift in our understanding of the Quaternary geological history for this region. To test this claim, we conducted an extensive examination of the purported stratigraphic conditions within 54 gravel pits situated south of the Middle Swedish End Moraine Zone (MSEMZ). The presence of a covering till bed on top of glaciofluvial sediments could only be confirmed in 22% of the gravel pits, and these sites were almost exclusively associated with ice-margin standstills/oscillations during the Late Weichselian deglaciation. In all other gravel pits where covering till could not be verified, ventifacts occur in several stratigraphic positions: at the contact between glaciofluvial and overlying littoral sediment, redeposited ventifacts within littoral sediment, and ventifacts at the contact between glaciofluvial or littoral sediments and overlying aeolian sediment. We conducted an extensive luminescence dating program (comprising 74 samples) in 22 of the gravel pits to determine the age of the ventification by dating underlying and overlying sediments. We conclude that wind abrasion across southern Sweden was not a single simultaneous event but rather a time-transgressive or recurrent process. It occurred in close conjunction with local deglaciation in some instances, while in others, it transpired later, extending into the Early Holocene. Notably, none of the encountered ventifact surfaces are of a pre-LGM age. For sites along the west coast, the evidence indicates a first wind abrasion event during periglacial conditions roughly between 17 and 16 ka. In upland sites, ventifact formation either occurred immediately after deglaciation, during the Bølling−Allerød interstadial complex (14.7−12.8 ka), or during the Younger Dryas. Even though the ice margin was situated far to the north of these sites during the latter event, concurrent patterned ground formation suggests a harsh climate with reduced vegetation cover, leading to sand drift and ventifact formation in both coastal and upland areas. In some locations, the sand drift and subsequent aeolian sediment deposition persisted into the Early Holocene. Based on our stratigraphic investigations and dates, we reject the idea that southern Sweden's glacial landscape was shaped primarily during the Saalian.

Coupled luminescence and cosmogenic nuclide dating of postglacial deflation surfaces and sand drift on a raised ice-contact delta at Veinge, SW Sweden

Wind-abraded cobbles (ventifacts) and aeolian sand are known from the sandy-gravelly coastal areas of south-western Sweden, especially in association with raised deltas. Ventifacts are recorded on at least two different stratigraphic levels, at some sites atop glaciofluvial sediment, at other sites atop littoral deposits, and in some places at both levels, while aeolian sand usually forms a surficial cover. The formation of ventifacts has usually been coupled to abrasion due to katabatic winds from the retreating ice sheet or with periglacial climate during the Younger Dryas stadial (12.8–11.7 ka).To determine the timing of these deflation events, we have applied a combination of dating methods to ventifacts and associated sediments on top of an ice-contact delta at Veinge, south-western Sweden. Quartz and feldspar luminescence dating as well as portable luminescence profiling has been used for littoral and aeolian sediments over- and underlying deflation surfaces, while rock surface luminescence burial dating and paired 14C–10Be cosmogenic nuclide dating were conducted on ventifacts. The results show that a first deflation event occurred c. 16.5 ka, just after deglaciation and prior to a regional transgression that peaked around 15.7 ka. At 12.4–11.4 ka, during the Younger Dryas stadial, a new set of ventifacts formed on the surface of the exposed littoral sands and gravels. Some wind abrasion also occurred in the early Holocene, but at c. 8.5 ka the surface was covered by aeolian sand, up to 2.5 m thick.The combination of different dating methods have allowed us to draw more informed conclusions on the timing and duration of these wind abrasion/transport events than would have been possible from the use of only single-method dating. It has also made it possible to infer some environmental conditions during deposition. For example, both glaciofluvial and littoral deposits show evidence of incomplete bleaching of the luminescence signal. This suggests short subaerial transport and brief reworking by waves, respectively, though bleaching conditions improved during shore regression. Rock surface burial luminescence profiles reveal that some ventifacts were repeatedly exposed, but that later event(s) were shorter in duration as indicated by quartz-feldspar age comparisons.

Characteristics of wind-sand transportation along railways in the eastern fringe of the Taklimakan Desert and sand control system

Abstract This paper focuses on the Korla-Ruoqiang desert railway line, utilizing ERA5 (ERA5 is the fifth generation of ECMWF (European Centre for Medium-Range Weather Forecasts) atmospheric reanalysis global climate data) wind data to conduct a comprehensive analysis of the wind energy environment along the line in all aspects, reveals the characteristics of wind-sand transport, and puts forward the countermeasures to prevent and control wind-sand disasters. The results of the study indicate that: (1) the wind-sand along the line mainly occurs in the spring and summer seasons, and the dominant sand-moving directions are easterly (ENE, E and NNE) and northeasterly (NE). (2) The average annual sand-moving wind speed ranges from 5.80 m/s to 7.25 m/s, and the annual frequency of sand-moving ranges from 11.99% to 37.26%. (3) The annual sand drift potential (DP) along the line ranges from 69.20 VU to 607.24 VU, with three types of wind energy environments: low, medium and high. The resultant drift potential (RDP) ranges from 45.52 VU to 547.49 VU, and the wind variability index (RDP/DP) is between 0.54 and 0.90. (4) The average sand transport quantity along the line ranges from 2.92 m³/m/a to 9.09 m³/m/a. Based on these results, we optimize the sand blocking, sand fixing and wind erosion prevention measures for different types of wind-sand environments, establish a scientific and efficient wind-sand protection and control system to solve the wind-sand problems and provide a scientific foundation for the prevention and control of wind-sand disasters along the line.

Evaluating temporal sand drift potential trends in the Sistan region, Southeast Iran.

The Sistan region in Southeastern Iran is one of the world's most sensitive areas when it comes to sandstorms and wind erosion. One of the most influential factors in interpreting sandstorms is sand drift potential (DP), which is directly related to wind speed. Accurately, monitoring this phenomenon is still being determined, considering various temporal scales. Therefore, the main aim of this research is to analyze the trend of DP on monthly and annual scales. Our results showed that monthly variations of DP reached the highest and lowest values in July (609 VU) and January (47 VU), respectively. Blowing sand predominantly moved southeast, and the directional index fluctuated from 0.88 to 0.94. The annual DP was measured equal to 2700 VU, signifying a relatively high value when compared to other arid regions worldwide. The trend analysis results obtained from the Mann-Kendall test revealed both positive trends during the period 1987-2001 and negative ones from 2002 to 2016). However, the positive trend was found statistically insignificant. Furthermore, Sen's slope test results demonstrated that a negative trend could be observed with a steeper slope during July, September, and August, while a positive trend could be observed with a steeper pitch during November, December, and June. We recommend that land managers and stakeholders involved in controlling blowing sand using biological and physical methods should consider these trends in the Sistan region. Implementing nature-based solutions or control strategies should focus on these temporal sequences.

Fighting drift sands with pine trees: Reforestation of coastal areas of NW Portugal at the end of eighteenth century

From the late Middle Ages until the end of the nineteenth century, the northwest coast of Portugal was severely affected by drift sands, which led to the disappearance of villages or forced the population to migrate or suffer several losses. Along the northern European Atlantic coast, the most effective response to the drift sands was the reforestation of coastal areas, starting from the end of the eighteenth century and in the nineteenth century. In the northwest coast of Portugal, until the end of the nineteenth century, coastal planning and management was mainly the responsibility of local civil, manorial, and religious institutions. Based on historical sources, monastic institutions' forest management actions will be analyzed, and whether these initiatives successfully made communities in north-western Portugal less vulnerable to drift sands. This study will also allow a comparison of how the coastal landscape in the Portuguese Northwest has been reshaped and managed over two centuries, the profound impacts caused by tourism activities in the second half of the twentieth century, and the implementation of coastal management plans by the Portuguese State from 1993 onwards.

Dune movement under climatic changes on the north‐eastern Tibetan Plateau as recorded by long‐term satellite observation versus ERA‐5 reanalysis

AbstractThe movement of active dunes is tightly linked to climatic conditions (e.g., wind regime, temperature and precipitation) as well as human influence (e.g., grazing, dune fixation and greening). Dune migration rates can be studied to draw conclusions of changing wind conditions over time. The Gonghe Basin (GB), located on the north‐eastern Tibetan Plateau (TP), offers a good testing ground for these assumptions. The intramontane basin is highly influenced by two major wind regimes: the mid‐latitude Westerlies and the East Asian summer monsoon. To investigate environmental changes, this study combines optical remote sensing techniques with climatic datasets. High‐resolution satellite images of the last five decades, such as CORONA KH‐4B, are used to map dunes and calculate their respective migration rates. Further, height information was extracted as well. Climatic changes from the ERA‐5 reanalysis dataset and normalized difference vegetation index (NDVI) values were processed alongside. Relating the dunes' surface processes to climate model data shows an accordance between slowing migration, expanding vegetation and a decrease in sand drift potential. From 1968 to present time, an average dune migration rate of 7.3 m a−1 was extracted from the satellite images, with an overall reduction of −1.81 m a−1. The resultant drift potential (RDP) values for the GB are calculated to be below 10 m3 s−3 with a spatial decrease, following a direction from the NW to the SE, fitting well with a corresponding decrease in the migration rates. Our results indicate a good agreement between the development of aeolian landforms and the ERA‐5 climate reanalysis model data, even in a high‐altitude setting with complex topography, which is known to influence such datasets.

Managing Coastal Sand Drift in the Anthropocene: A Case Study of the Manawatū-Whanganui Dune Field, New Zealand, 1800s-2020s

Abstract In the Anthropocene, dunes act as a natural defence from sea-level rise and storm surges while providing 'ecosystem' services. This article uses scientific and historical data to examine the Manawatū-Whanganui dune field in New Zealand from the nineteenth to the twenty-first century. Dunes that were destabilised due to European settlements and their activities were drifting inland causing social, economic and political problems. Attempts to prevent dune mobility occurred at the time in many parts of the world. Thus, knowledge was shared between countries through experts and migrants. The consequences of the implemented solutions and new environmental conditions mean that dunes are still a major issue in the region. A comparative analysis of historical and present-day dune management practices provides a better understanding of long-term dune drift. In conclusion, interdisciplinary analyses of long-term relations between dunes and society must be taken into account for their holistic management.

Relationship between Fields, banks and farmstead at an early Iron Age site in Northern Denmark

Ancient Celtic fields are still visible as banks and lynchets in many landscapes in Northwestern Europe today. Comparably little is known about the relationship between Celtic fields and the dwellings of the people farming these fields. Excavations of a pre-roman Iron Age field system near Aalborg, Northern Denmark, revealed the remains of a farmstead (longhouse) and fields covered by drift sand. The site is located on raised late Holocene marine foreland with very homogeneous sandy soil. This provided an excellent opportunity to study prehistoric manuring practices and spatial relationships between fields and the farmstead. Archaeological excavation, soil geochemistry, particle size analysis, macrofossils and radiocarbon dating were combined to establish a chronology and land-use history of the site. The results showed that the farmstead was established around 400 BCE, while drift sand covered the fields around or shortly after 200 BCE. The investigation revealed ard marks covering most of the excavated area, while field boundaries delimited at least six fields. The longhouse was located between two field boundaries. Particle size analysis of marine sandy plough-layer revealed that earthy material had been added from adjacent uphill areas, while a field bank was a mixture of the plough layers from its two adjacent fields. However, all results suggested a limited input of plant nutrient, manure and earthy material taking the century long farming into account. The excavated fields may hence represent a short lived expansion of fields into more marginal and naturally less fertile land. The size of the farmstead was nevertheless comparable to other longhouses found in contemporary villages in the area, suggesting that the nutrient-poor soil did not necessarily mean poor living conditions for the inhabitants.

Geomorphological Changes by the Action of Coastal Processes and Anthropogenic Activties along the Coastal Zone between Ras Al-Jalaiah And Ras Az-Zour, Southern Kuwait

The coastline is one of the most important linear features on the earth’s surface, which displays a dynamic nature. The natural processes that interact with the coastal environment of Kuwait are tides, currents, and waves. The main shoreline of the coast of Kuwait is about 325 km long. In the north, the coast is characterized by wide intertidal mudflats, bounded by a large-scale coastal sabkha, partly covered with sand drifts. The southern shore is characterized by relatively steep sand beaches with narrow to moderately wide rocky intertidal platforms, which are partly covered by sand and algal mats. The area of interest is the coastal area between Ras al-Julaiha and Ras Az-Zour in the southern area of Kuwait. Sandy berm and wave-cut cliff bound this southern intertidal environment. The study area is a superficial, open, vulnerable bay of a maximum depth of 28 m extending along the southern shore of Kuwait. Ras Al-Jalaiah promontory bounds the area northwards and Ras Az-Zour promontory bounds it southward, with a distance measured vertically of 18.085 km.

Numerical Investigation on Impact Erosion of Aeolian Sand Saltation in Gobi

Sand drift erosion is common on aeolian landforms, particularly in the Gobi desert where sand drift is often quite strong. Sand drift erosion can lead to many types of hazards, including severe crop loss, structural damage to buildings or infrastructure, and abrasion of soil or clay components that contribute to the production of fine particulate matter. This article combines the Gobi sand flow model with the solid particles erosion model to simulate the sand drift erosion process in a variety of Gobi environments. The results show that the impact erosion of saltation particles is highly dependent on both the friction velocity and the gravel coverage. Saltation erosion amount increases with the increment of friction velocity and the gravel coverage. The vertical profile of saltating erosion rate displays a clear stratification pattern composed of a linear increasing layer, a damage layer, and a monotonic decreasing layer. The maximum value of the saltation erosion rate increases as the friction velocity increases and their curve shows a power-law relationship. The damage height caused by saltation erosion is primarily concentrated in the height range of 0.03 m to 0.15 m, and it increases approximately linearly with friction velocity.

A multi-staged drift sand geo-archive from the Netherlands: New evidence for the impact of prehistoric land use on the geomorphic stability, soils, and vegetation of aeolian sand landscapes

The drift sand area near Hilversum, the Netherlands, holds a geo-archive with multiple drift sand phases and intercalated palaeosols. We studied this area to test earlier theories on the development of podzols in such aeolian sands, the occurrence of sand drifting, and the contemporary vegetation development, and to gain insight into the early human impacts on these fragile ecosystems. Based on OSL and radiocarbon datings, palaeoecological studies, and soil chemical analyses, the age and origin of the drift sand phases and palaeosols were established. Sand drifting started around 6000 BCE (Late Mesolithic), the drift sand covering a distinct podzol in the Younger Cover Sand II. A second Late Mesolithic drift sand phase dated from ca. 4900–4500 BCE. Three later drift sand phases were distinguished of which the last is the classic Late Medieval (and younger) phase, while the first two date from the Neolithic. All intercalated palaeosols exhibited more or less prominent podzolisation. The palaeocological data showed that, prior to the Neolithic, in the forest open patches had developed with non-arboreal vegetation, dominated by Poaceae and Ericaceae. This changed during the Neolithic, most probably linked to the introduction of crop farming, the vegetation gradually acquiring the characteristics of the classic heathland with patches of trees/shrubs. The early sand drifting, podzolisation and opening of the forest are attributed to Mesolithic land use, with intentional burning as major factor. We conclude that the local destruction of the deciduous forests by fire and associated creation of open patches with bare sand were essential for the early sand drifting and podzolisation to occur. The results shed new light on the origin of drift sands, heathlands, and podzols in the Netherlands, and on the environmental impacts of Mesolithic people, and testify to the fundamental instability of these dry inland dune ecosystems.

Simulation of Urban Areas Exposed to Hazardous Flash Flooding Scenarios in Hail City

According to the United Nations (UN), an additional 1.35 billion people will live in cities by 2030. Well-planned measures are essential for reducing the risk of flash floods. Flash floods typically inflict more damage in densely populated areas. The province of Hail encompasses 120,000 square kilometers, or approximately 6% of the total land area of the Kingdom of Saudi Arabia. Due to its innate physiographic and geologic character, Hail city is susceptible to a wide variety of geo-environmental risks such as sand drifts, flash floods, and rock falls. The aim of this work is to evaluate the rate of urban sprawl in the Hail region using remote sensing data and to identify urban areas that would be affected by simulated worst-case flash floods. From 1984 to 2022, the global urbanization rate increased from 467 to 713% in the Hail region. This is a very high rate of expansion, which means that the number of urban areas exposed to the highest level of flood risk is rising every year. With Gridded Surface Subsurface Hydrologic Analysis (GSSHA), a wide range of hydrologic scenarios can be simulated. The data sources for the soil type, infiltration, and initial moisture were utilized to create the coverage and index maps. To generate virtual floods, we ran the GSSHA model within the Watershed Modeling System (WMS) program to create the hazard map for flash flooding. This model provides a suitable method based on open access data and remote data that can help planners in developing countries to create the risk analysis for flash flooding.

Morphological dynamics of a trough-shaped blowout on a fixed dune in China

• There is a strong link between blowout morphology and the pattern of airflow. • The pattern of airflow within blowout is related to the regional wind direction. • Airflow undergoes separation and deflection in the leeward of the deflation basin. • Corkscrew vortices are the determinant of upwind expansion of the deflation basin. The formation and development of blowouts is an important surface indication of sand drift activity in semiarid grassland areas; thus, an accurate understanding of their morphological evolution characteristics and dynamic processes is of significance for grassland desertification control. This study analyzed the long-term topographic change of a trough blowout developed on a fixed sand dune in the Otindag sandy land of China via ground measurements from 2011 to 2020 and examined the short-term airflow structure through field observations. The results indicated that the area of the deflation basin shows a state of continuous growth. The expansion of the deflation basin was most obvious on the western, southwestern and southern slopes, which is contrary to the regional prevailing wind direction. As airflow passes over the blowout, there is significant airflow steering with the change in topography, and the degrees of airflow steering and acceleration are determined by the direction of the approaching wind. Airflow expands and decelerates on the leeward side of the deflation basin, causing flow separation and producing a recirculation zone on the sheltered lee slopes. Based on a detailed analysis of the results, we suggest that the soil collapse and sand avalanches caused by vortices are the main reasons for the upwind expansion of the deflation basin. Collectively, these findings reveal a strong link between the blowout morphology and the airflow pattern.

Wind Tunnel Experiments and Field Observations of Aeolian Sand Encroachment around Vernacular Settlements in the Saharan and Arabian Deserts

One of the key repercussions of the desertification process in the Sahara and the Arabian desert is increased aeolian sand drift and sand deposition. Despite its isolated location and severe desert climate—particularly in terms of solar radiation, sand drift, and sand deposition—the region of El-Oued Souf in the Grand Erg Oriental in the Algerian Sahara has been a key cultural and trade center for many centuries. To resist the extreme weather conditions, the architecture of the vernacular settlements in the region of El-Oued Souf has unique design traits. Newly constructed buildings, on the other hand, frequently employ technologies based on models imported or imposed from climates that bear little resemblance to the desert. As a result, the inhabitants of these structures live more ‘in the desert’ than ‘with the desert’. This study investigates the impact and the effectiveness of vernacular desert architecture to resist aeolian sand encroachment problems in sandy desert areas. The sand accumulation patterns around vernacular buildings were identified and quantified using wind tunnel experiments. The size and shape of the buildings, as well as their geometric configuration within the settlement, were investigated in relation to the shape and dimension of sand accumulation formations. Field observations in north Algeria and the United Arab Emirates confirmed the accumulation patterns produced by the wind tunnel experiments. The study proposes possible design indicators for building forms to minimize the impact of sand deposition on such forms.

Holocene insect pioneer colonization of post-glacial dune sands exemplified by tiger beetle burrows

Many ecosystems today in temperate zones are the result of colonization of barren substrates deposited or exposed as a result of deglaciation, around the start of the Holocene. Direct evidence of post-glacial colonization, in the form of life traces such as tracks and burrows, is typically rare and erased by later succession unless buried deeply within a short time interval, as is possible in dune sands. Tiger beetles (Coleoptera: Cicindelidae) are an example of early successional tracemaking colonists widely distributed in open habitats worldwide and are well known from coastal and inland dunes in Europe today. Coastal dunes at the Vistula Spit in Poland, dating back to the time of post-glacial stabilization of modern Baltic Sea levels, contain buried long, narrow, subfossil burrows, which are variable in shape. Some of them resemble linear or J-shaped burrows made by living cicindelids both in situ in exposed drift sands within the inland European Sand Belt and in laboratory settings after being wild-caught. A new locality for the modern Viennese tiger beetle Cylindera ( Cicindela) arenaria viennensis, Schrank, 1781, whose larval burrowing was examined for reference, is reported at Mnin in the Przedbórz Upland, Poland, where there was a suitable substrate made up of aeolian sand deposited earlier in the Holocene but opened up by mining. The subfossil burrows at the Vistula Spit, if they were made by cicindelids and other early successional species, could represent similar colonization of comparable pioneer habitats dating back millennia when those coastal dunes were young. Although the body fossil record of tiger beetles is very poor, ichnological evidence of their potential presence may be useful for inferring their biogeographical history, complementing prior knowledge from modern distributions or phylogenetic histories.

Effects of Covering Layer of Sand Particles on Particle‐Bed Collision and Aeolian Sand Transport

AbstractThe movement of sand particles on the desert is the primary mechanism resulting in the development of sandstorms. Scientists have found that the physicochemical environments of terrestrial planets can cause the surface of sand particles to form a peelable covering layer, which may shed gradually during the movement of sand particles and affect the collision process between sand particles and bed surface, and finally affect aeolian sand transport itself. However, only a few studies have investigated these microscopic physical processes and conducted quantitative analysis of the relationship between covering layer mass and its coefficient of restitution (COR) when a particle impact desert surface. In this study, we collected four types of natural sand particles from the Badain Jaran, Mu Us, and Taklimakan deserts and the shoreside of the Yellow River respectively. A hydrochloric acid solution was used to dissolve the surface‐covering layer of sand particles, and high‐speed photography was used to capture the process of particle‐bed collision. The motion characteristics of the sand particles under different covering layers were analyzed using statistical analysis, and the quantitative formula between the COR and the covering layer mass was provided. This calculation result was further incorporated into an aeolian sand transport model to evaluate the effect of the covering layer on sand flux. Considering the ubiquity of covering layer on sand particle, the methodology proposed in this study can be used to simulate sand drift on Earth, Mars, and other terrestrial planets more accurately.