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Dust storms are a major cause of central Sonoran Desert weather fatalities. Through back-trajectory analysis of North American Monsoon dust storms in central Sonoran Desert of the United States. This study is specific to central Arizona (USA) from 2009 to 2022 using the HYSPLIT model. Our findings have shown that dust storms originate from southerly or near-southerly regions. The dust storms displaying the highest concentrations of particulates show a preference to originate from the southwest. This coincides with the development of a 500 hPa ridge to the east of the study area. The highest concentration storms' back-trajectories display the lowest heights above the ground. Given their southwestern origin, these storms travel upslope along the seasonally dry river beds of the Gila River and its tributaries. Weaker dust storms originate over a wider area with a shift to a southerly direction. Such origination indicates that weaker dust storms are traveling downslope through the washes and channels of the dry Santa Cruz River. As dust concentrations drop, storm direction drifts east and dust height is suspended higher. This paper highlights the spatial variations in central Arizona dust storms, showing the likeliest paths of the strongest events and assists in identifying aeolian dust origins. • Identification of source regions of dust storms impacting the central Sonoran Desert located in the Arizona region of the Southwestern United States. • Use of the HYSPLIT back trajectory model. • Most large dust storms impacting central Arizona have a southwestern origin, having traveled upslope along the normally-dry Gila River and its tributaries. [ABSTRACT FROM AUTHOR]

In the hyperarid Atacama Desert (Northern Chile), the economic and social development is supported using fossil groundwater. The groundwater extraction (GWE) has significantly increased over the last 30 years, reaching ∼4.2 m3.s−1 in 2018 (+1890%) at the Pampa del Tamarugal Aquifer (PTA). But opposite assumptions lead to uncertainties concerning the role of the increasing anthropogenic pressures and the ephemeral recharge events in the water table (WT) variations. This paper analyzes: (i) the long-term groundwater levels changes between the late 1950s (post Saltpeter Work) and the early 2010s, and (ii) the short-term response of groundwater levels, based on the analysis of the 1998–2018 WT time series at 10 observation boreholes. Results indicate that the WT variations in space and time are strongly related to the anthropogenic pressure changes. Since the late 1950s, the WT is declining in the major part of the PTA. Nevertheless, local reduction of GWE together with ephemeral recharge events in alluvial fans allowed local WT rises. But after a large GWE increase (+114%) between 2004 and 2006, all observation boreholes highlight a general WT decline (−9.8 ± 5.8 cm.yr−1). Over the years, anthropogenic pressures became the dominant factor of the WT variations and led to overuse the aquifer. • Groundwater use has increased 1890% over the last 30 years. • Water table variation in space and time depends on anthropogenic pressure changes. • Water table decline averages ∼10 cm.yr-1 over the 2008–2018 decade. • Recharge events from floods do not outweigh groundwater use increase. • Pampa del Tamarugal Aquifer is overexploited. [ABSTRACT FROM AUTHOR]

Abstract: The paper discusses the changing relationship between pastoral nomads and farmers, one of the recurring themes in the history of the arid Near East. In many parts of this region that history has often been characterized in terms of changing cycles of sedentary farming and pastoralism, linked respectively to notions of cultural florescence and collapse. The paper reviews the complex history of cultivation, herding, and industrial activity (copper mining and processing) that has been established for the Wadi Faynan in southern Jordan, a desertic region used today largely by Bedouin herding groups, from the Early Bronze Age to the present day. As recent studies indicate for the Negev region as a whole, it concludes that notions of simplistic cycles in nomad–sedentary relations are unhelpful: historical contingency played a far more important role than the physical landscape and the changes effected to it by climatic shifts over the past 6000 years. [Copyright &y& Elsevier]

Mammalian species inhabiting arid landscapes exhibit various levels of mobility in order to cope with unpredictable spatiotemporal dispersion of resources. However, the space use and ranging behavior of many species in drylands is poorly understood, especially for large carnivores in Asia. Accommodating the long-distance movements of mammalian carnivores is a major challenge in conservation, particularly for threatened and highly mobile species. The Asiatic cheetah Acinonyx jubatus venaticus , a critically endangered subspecies found only in arid areas of Iran, exhibits high levels of mobility. In the absence of satellite collars, this paper outlines ranging patterns of the majority of the Asiatic cheetah’s known population. A total of 17 independent cheetahs (11 males; 6 females) were detected with camera traps that were deployed on eight reserves between January 2011 and May 2016. The animals displayed extensive movements (up to 217 km between furthest known locations) and at least nine adult cheetahs were known to move between multiple reserves in central Iran. This mobility may follow a “nomadic” ranging pattern, a non-sedentary behavior with irregular timing and movement directions. The ranging behavior documented here must be considered when designing monitoring efforts to determine population and occupancy trends for this wide-ranging elusive carnivore. Although preliminary, our results show that improving protection beyond the current network of cheetah reserves, particularly along corridors, should be a top priority to safeguard the persistence of the Asiatic cheetah. [ABSTRACT FROM AUTHOR]

The characteristics of the wind regime and the development of dune morphology in the Taklamakan Desert have been the focus of scholars. In this study, we used ERA5 reanalysis wind data at a height of 10 m from 1979 to 2019 to examine the sand transport and wind regime characteristics of the entire Taklamakan Desert. We combined the two latest dune development modes, i.e., bed instability and elongation modes, and determined that: (1) Taklamakan Desert is overall characterized by a lower wind energy environment; the wind and sand activity intensities are highest in the eastern part of the desert, with a decreasing trend from the east to the west. The wind direction in the eastern region shows unimodal characteristics due to the backward easterly wind; the wind regime gradually becomes complicated from the northeast to the southwest; (2) the morphological alignments of dunes can be predicted by such modern wind regimes combined with the latest dune development modes. Large longitudinal dunes in the middle of the desert can be predicted with the elongation mode, whereas secondary transverse dunes, which derive from these composite dunes, can be predicted using the bed instability mode. Collectively, this paper fills the gap of the lack of uniform and standardized macro-scale wind data in the Taklamakan Desert, and the two modes of dune development derived from ERA5 reanalysis data can match the morphology and trend of most modern dunes. • The wind regime in Taklamakan Desert was examined using ERA5 reanalysis data. • ERA5 reanalysis wind data can be used to explain the morphology of modern dunes. • Two dune development modes can predict the alignments of most sand dunes in the desert. [ABSTRACT FROM AUTHOR]

Groundwater resources are essential to underpin the daily life of communities in remote regions. Hydrogeological studies in these areas are complex, largely due to the absence of long water table records and to the difficulties involved in accessing some relevant locations. This hampers attempts to manage local resources. Devising cost-effective methods to explore these aquifers is important to understand how they work and to come up with adequate protection strategies. This paper deals with the joint application of Geographic Information Systems (GIS) tools and numerical groundwater models to explore groundwater resources in desert areas. The method is illustrated through its application to Erg Chebbi, a water table aquifer located in southern Morocco, which supplies drinking and irrigation water for local communities while also underpinning agriculture and tourism. The geometry of the aquifer was established based on existing cartography, GIS and a field survey. This led to the development of a steady-state numerical model. Modeling results suggest that the aquifer has been depleted by almost 30% due to groundwater extractions in less than 50 years. The average drawdown was found to be in the order of three meters. This corresponds to a total depletion in the order of 20-60 Mm3. [ABSTRACT FROM AUTHOR]

This paper discusses developing a novel spectral index for desert sand dunes detection using four bands from Sentinel-2 data. This index, called Normalized Difference Enhanced Sand Index (NDESI), uses the blue band (492 nm), the red (664 nm) or the Vegetation Red Edge (VRE) band (782 nm), and two of the Shortwave Infrared (SWIR) bands (1613 and 2202 nm) to generate a grayscale image, where DN values are within −2 to 2. The lowest and highest values represent water bodies and sand dunes, respectively. A threshold calculation technique was used to generate a unique threshold for each image. This index application on several images covering the northern region of Figuig city seems to perfectly highlight sand dunes all over the image, with an overall accuracy of 97.9% and a kappa coefficient of 83.4%. This index is adapted for Landsat 8 data and can track sand dunes change over time. • New spectral index for desert sand dunes detection and monitoring. • Made for Sentinel-2, Landsat-8 and any sensor that have the required bands. • Can discriminate sandy surfaces from soils and alluvium. • Have good accuracy for sand dunes detection. [ABSTRACT FROM AUTHOR]

Abstract: Carbon stocks and carbon accumulation in the earth''s drylands have gained increasing attention. The winter-cold deserts of Middle Asia, i.e. in Kazakhstan, Uzbekistan, and Turkmenistan, cover an area of 2.5 million km2. Within these deserts, the two Saxaul species White Saxaul (Haloxylon persicum Bunge ex Boiss. & Buhse) and Black Saxaul (Haloxylon aphyllum (Minkw.) Iljin) are dominant woody species with a potential distribution area of about 500,000 km2. From the 1950s until today, the Saxaul vegetation has been degraded through logging and over-grazing. In this paper, we estimate the current and potential living above ground and below ground biomass of the Saxaul vegetation and its carbon stock. The living above ground biomass ranges between 1.5 t/ha and 3 t/ha. The potential carbon stocks above ground and below ground amount to 29.4–52.1 million t and 22–81.4 million t, respectively. Today, only 11%–28% of the potential biomass and carbon stock have remained. The carbon stock of the Saxaul vegetation is low compared to other ecosystems of the earth, but restoration and conservation of Saxaul vegetation is one way to sequester carbon through vegetation for Uzbekistan and Turkmenistan, which do not have much other woody vegetation. [Copyright &y& Elsevier]

Abstract: Despite the arid desert condition of the southern periphery of Israel, the entire area has an abundance of remnants from ancient agriculture of which a massive system of terraced wadis constitutes the main component. The goal of this paper is to date the agriculture terraces based on the high-resolution data collected during the 1980’s in the frame of the Negev emergency survey (conducted by the Israel Antiquities Authority) and later studies. Analysis of the distribution areas of the terraced wadis shows a constant correlation only with farmhouses of the Byzantine and Early Islamic periods. Excavations conducted in hundreds of sites yielded finds of the 6–8th centuries CE only. It was found that the distribution areas of the desert agriculture spanned both the Northern Negev, located within the range of dry farming of the sedentary land, and the extreme desert of the Sinai Peninsula. The correlation of the terraces and settlements with the boundaries of the Byzantine desert province Palestina Tertia, raises the possibility that the enormous effort needed to pave the desert with water management facilities reflects an imperial initiative. It is assumed that the agriculture practiced in all other periods was a simple, spontaneous agriculture of the kind that is practiced in the desert by present-day Bedouin, and constitutes only a secondary element of their economy. [Copyright &y& Elsevier]

Abstract: In the Tarim River Basin, the desert riparian forest vegetation is under high-temperature and aridity stress. However, the vegetation can grow continuously because of deep rooting that can reach groundwater, which can thus redistribute water into the upper soil profile. This paper describes patterns of hydraulic lift by Populus euphratica Oliv. and discusses its ecological effects. Our results show that the tap root sap velocity of P. euphratica Oliv. is positive during the day and night. However, a reverse sap flow was observed in the lateral roots during the night. The soil water content of the subsoil was higher than that of the topsoil at depths of 0–120cm. When the sap flow of the lateral roots was reversed at night, the soil water content clearly increased. In particular, at depths of 60–120cm, the soil water content at 4:00 was 28–38% greater than that at 16:00. The vapor pressure deficit was a factor that predominantly affected the root sap velocity, and the smaller vapor pressure deficit often facilitated a reverse sap flow in the lateral roots. Our findings demonstrate the hydraulic lift characteristics and ecological effects that occur in the desert riparian forest in extremely arid regions of middle Asia [Copyright &y& Elsevier]

Abstract: Desert kites are stone-built, funnel-shaped installations comprising two long and low stone-built walls (‘arms’) converging on an enclosure or pit at the apex. They are found in the deserts of the Near East, and are generally accepted as representing game traps to catch herds of wild ungulates. Their chronology is debated but some desert kites appear to have functioned as early as the 7th millennium BC. The largest number of these structures is recorded in the deserts of eastern Jordan where they often form chains of up to 60km long. In contrast, in the Negev (Israel) and Sinai (Egypt) deserts, the desert kites are few in number and occur as small, individual installations. This paper presents the results of archaeological surveys and excavations of 16 desert kites from the Negev desert and northeast Sinai. We present radiocarbon dates, infrared stimulated luminescence ages and chronology of material culture to show that desert kites in this region were established in the late 4th–early 3rd millennia BC and ceased to function by the mid-2nd millennium BC. The size, shape and location of the desert kites fits the physical conditions of the terrain and also the ethology and ecology of the prey species hunted. [Copyright &y& Elsevier]

Abstract: This paper reviews and summarizes the results of research projects conducted in the Aleppo pine provenance trial in the Yatir forest, located at the northern edge of the Israeli Negev desert, under semi-arid climate. Results show that to improve the sustainability of new Aleppo pine plantations at the edge of deserts, prospective seed sources (provenances) must be selected for heterozygosity on one hand, and for drought resistance and water-use efficiency on the other. Harsh environmental site conditions at the desert''s edge provide an opportunity to exert heavy selection pressure among and within provenances of a priori drought-tolerant species. The survivors should be used as the seed source for new forest plantations aimed at combating desertification. [Copyright &y& Elsevier]

Abstract: The Kuwaiti desert is swept by strong winds, particularly by northwesterly wind, during the summer months (April through September), causing mass-scale sand transport that poses a serious environmental hazard. Understanding that accurate transport rate data are very difficult to obtain either by field measurements or by using any existing sand transport formulae, this paper presents a mathematical model to predict the sand-transport rate for Kuwaiti desert by following a well-known theoretical approach of Lettau and Lettau (1978) and by taking into account the effect of seasonal wind variability. The validity of the model is next examined using the field data from the study of Al-Awadhi and Al-Sudairawi (2002). The examination showed that the model underestimates the rate of sand transport by an average ratio of 0.15. The application of the model, at some seven locations that are evenly distributed across the Kuwaiti desert, indicated that about 40% of the amount of sand transport in Kuwait prevails from the NW during the peak summer months (June and July). The resulting map of sand transport rate indicated that the zone of higher sand transport rate is located within the areas covered by most extensive mobile sand sheets and sand dunes. [Copyright &y& Elsevier]

Abstract: This paper documents the main features of climate and climate variability across the Monte Desert for the Last Glacial Maximum, the Glacial–Interglacial transition, and the Holocene on the basis of proxy records and for the 20th century using instrumental observations. The climate in the Monte is determined by interactions between regional physiography and atmospheric circulation in the 25–45°S sectors of South America. Although arid and semi-arid conditions prevail across the Monte, its large latitudinal extent and complex topography introduce many particularities at local scales. Paleoclimatic records and model simulations of past climates suggest significant variations in the atmospheric circulation, temperature and rainfall patterns since the Last Glacial Maximum. High-resolution proxy records east of the Andes support the existence of complex climatic patterns with similar temperature changes across the whole region but opposite precipitation variations between subtropical and mid-latitude sectors in the Monte during the past millennium. The present-day climate is depicted in terms of the space and time variability of the near-surface temperature, rainfall and tropospheric wind patterns. Uneven temperature trends over the Monte were recorded for two separate (1920–44 and 1977–2001) global warming periods in the 20th century. Additional warming evidence in the region is provided by extreme temperature records. The non-homogeneous regional pattern of precipitation shows a positive long-term increase between 30 and 40°S during the interval 1985–2001. Ensemble of climate experiments accomplished with general circulation models provide the most likely changes in temperature and rainfall to occur by the end of this century in relation to present climate. Temperature increases, larger in summer than in winter, will be concurrent with more abundant precipitations in summer, but almost no changes or even small reductions in winter across the Monte. [Copyright &y& Elsevier]

Abstract: Rodents from arid and semi-arid deserts are faced with the problem of water conservation. The physiological responses of small rodents to such conditions have been intensively investigated over broad geographically disjunct areas. Despite the presence of xeric habitats in South America since the late Tertiary, some studies suggest that sigmodontine South-American desert rodents do not display the same diversity of physiological responses at the species level as those observed in other desert-dwelling species of rodents. In this paper, we analyzed the physiological responses to water deprivation, at the interespecific and interindividual level, among eight species of sigmodontine desert-dwelling rodents from different geographical areas within South-American deserts. Using randomization tests, we found no significant phylogenetic signal for resistance to water deprivation or for individual variability in this response. Contrary to our initial predictions, we observed that sigmodontine rodents from arid/semi-arid habitats (Monte Desert) had significantly lower rates of body mass loss per day (higher tolerances to water deprivation) than species from the hyperarid deserts. We showed that sigmodontine rodents from South America showed a remarkable diversity of physiological mechanisms for coping with water shortage resulting from different evolutionary adaptive strategies. This diversity, however, displays a rather unexpected pattern in terms of its geographical distribution. [Copyright &y& Elsevier]

Abstract: We investigated the effects of winter and summer drought on a shrub/grass community of the Colorado Plateau in western North America, a winter-cold, summer-hot desert that receives both winter and summer precipitation. Summer, winter and yearlong drought treatments were imposed for 2 consecutive years using rainout shelters. We chose three perennial species for this study, representing different rooting patterns and responsiveness to precipitation pulses: Oryzopsis hymenoides, a perennial bunch grass with shallow roots; Gutierrezia sarothrae, a subshrub with dimorphic roots; and Ceratoides lanata, a predominantly deep-rooted woody shrub. Growth for all three species was far more sensitive to winter than to summer drought. The primary reason was that plants did not grow in summer and also did not appear to use summer-assimilated carbon to support growth in the following spring. We hypothesize that the relative scarcity and uncertainty of summer rain on the Colorado Plateau prevents most species from evolving adaptations that would improve their use of summer rain. Together with the results of the companion paper, which focused on plant water relations, we conclude that variation in fall to spring precipitation would have strong effects on primary productivity, and could cause reversible fluctuations in community composition, while increased variation in summer precipitation, through causing high rates of mortality among shallow-rooted species in dry years, has the potential to cause lasting and perhaps irreversible community change, especially if coinciding with the invasion of western landscapes by cheatgrass, tumble weed and other grazing tolerant exotics. [Copyright &y& Elsevier]

Ammopiptanthus mongolicus (Maxim.ex Kom.) Cheng f., an ancient relic of the Tertiary Period, is a rare and endangered species of Fabaceae in Mid-Asia desert and has been listed as one of primary protection plants by the Chinese government. Because of its high value of study and ecological usefulness in defending desert, this plant has been called ‘live fossil’. Using the leaves of A. mongolicus derived from water-stressed and water-supplemented environments at Shapotou in the south-east edge of Tengger Desert, seasonal changes of caloric values and osmotica, including free amino acids, total soluble sugar (TSS), sucrose, glucose and inorganic cations have been studied in this paper. The results showed that the main substances involved in osmotic adjustment varied with growth periods and between samples. At the early period it was soluble sugar mainly, and at the late period, besides soluble sugar, potassium and free amino acid (especially proline) also functioned. The higher levels of osmotica content (especially concentrations of total soluble sugar, sucrose, proline and potassium) and caloric values have been found in water-stressed plants rather than in irrigated ones. [Copyright &y& Elsevier]

This paper presents the seasonal features of major carbonaceous components in aerosols, their source characteristics and the role of meteorology in influencing the chemical characteristics of aerosols at a semi-arid location Udaipur (24.5°N; 73.6°E), India, based on the analysis of PM 10 samples (N = 128) collected during 2010–14. The samples were analysed for OC (organic carbon), EC (elemental carbon), CC (carbonate carbon), WSOC (water-soluble OC), WSTN (water-soluble total nitrogen) and water-soluble inorganic ions. Primary and secondary OC (POC and SOC), water-insoluble OC (WIOC) and water-soluble organic nitrogen (WSON) were also estimated. The carbonaceous aerosols (TC) contributed to ~23% of PM 10 loading. Both EC and OC mass loading showed high values during dry period (October to May) (OC = 26 ± 14 μg m−3, EC = 3.2 ± 2.2 μg m−3 with the PM 10 mass loading of 140 ± 52 μg m−3) compared to wet period (June to September) (OC = 16 ± 10 μg m−3, EC = 1.4 ± 0.8 μg m−3 with the PM 10 mass loading of 84 ± 43 μg m−3). While the crustal species, biomass tracers and anthropogenic species dominated during dry period, the sea salt species (Na+, Cl−, ss-SO 4 , ss-Mg, ss-Ca, ss-K) were comparatively higher in wet period. OC was found to be predominantly water-insoluble and secondary in nature. Local anthropogenic/natural emissions and marine transported aerosols (by south-westerlies) contributed during wet period, while dry period is influenced by transported anthropogenic aerosols from IGP and northern India (by north/north-easterlies) along with mineral aerosols from desert regions (by westerlies). Monthly average contribution of total carbonaceous aerosols (TCA = OM (organic matter) +EC + CC) varied from 20 to 42%, over a year while the water-soluble ionic fraction varied from 16 to 36% of the PM 10 mass. The un-analysed part which is mostly mineral dust contributed 39–55%. Image 1 • Carbonaceous and natural emissions show significant seasonal variation. • Mixing of anthropogenic pollutants with the dust of local origin. • South westerlies contribute during wet period. • Westerlies and north easterlies (from IGP) contribute during dry period. • ECR greater than unity indicate presence of more scattering type of aerosols. [ABSTRACT FROM AUTHOR]