Western Sahara Desert Research Articles

Assessing the stability of terrestrial water storage to drought based on CMIP6 forcing scenarios

Assessing the stability of terrestrial water storage (TWS) under drought conditions is critical for the sustainable development of water resources. In this study, we integrated surface temperature (ST), leaf area index (LAI), and precipitation (P) data from five different scenarios (History, SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) of the Coupled Model Intercomparison Project Phase 6 (CMIP6) to develop a standardized temperature vegetation precipitation index (STVPI). The index was then utilized to monitor global drought conditions and investigate the stability of TWS to drought disaster. The results showed that STVPI can not only monitor meteorological drought, but also has a remarkable sensitivity and applicability to drought caused by sparse vegetation. Notably, 21.16% of the global land area will have a drought trend under the SSP1-2.6 scenario, while it will rise to 35.81% under the SSP5-8.5 scenario, which underscored the potential for an expansion of drought-affected regions worldwide as a result of ongoing global warming and escalating emissions. In addition, the results also found that the warm temperate and tropical regions at lower elevations have an advantage in maintaining the stability of TWS. Unfortunately, the stability of TWS to drought will decline in the western Sahara Desert, central China and northern United States in the future, where will face a serious water crisis. The research framework provides an important reference for deeply evaluating and scientifically allocating water resources under climate change.

Sorcery or Science? Contesting Knowledge and Practice in West African Sufi Texts By Ariela Marcus-Sells

In late eighteenth-century West Africa, cycles of increasing violence and slave raiding sparked a desire for new modes of political organization. In the Sahel and savannah lands, there was a wave of military campaigns to establish Muslim-ruled states. In the western Sahara Desert, however, the Sufi Muslim theologians Sīdī al-Mukhtār (d. 1811) and his son and successor Sīdī Muḥammad al-Kuntī (d. 1826)—founders of the Kunta scholarly network—adopted a different model. Drawing on material and social capital acquired through trans-Saharan trade and pedagogical networks, they consolidated their position as socioreligious leaders, playing a pivotal role in the political developments of the late eighteenth and early nineteenth century. In Sorcery or Science? Ariela Marcus-Sells tells the story of Sīdī al-Mukhtār and Sīdī Muḥammad al-Kuntī through the prism of their writings on ‘the sciences of the unseen’ (ʿulūm al-ghayb). Through close analysis of these texts, Marcus-Sells looks at how the Kunta scholars defined and limited access to legitimate knowledge and practice, thus responding to—and shaping—the social authority under which they lived.

Maintaining Military Observers in the Middle of the Western Sahara Desert: A Logistic Challenge

Logistics plays a decisive role in any military campaign, including peacekeeping missions. In this article, we investigated how the United Nations Mission for the Referendum in Western Sahara (MINURSO) logistic system overcome the environmental challenges to support their United Nations Military Observers (UNMOs) deployed on Team Sites (TS) in 2017. Combining field experience with a wide-range analysis of relevant sources, key findings pointed out three critical factors: (a) the unique integration between civilian and military to provide logistic support despite the reduced number of military logisticians at the headquarter (HQ); (b) tactical aviation employment to supply TS, and (c) the use of operational contract support (OCS) to cover a lack of capabilities in the mission area. This work provides an overview of lessons learned about expeditionary logistical efforts for isolated troops. Furthermore, it will broaden the knowledge about supporting forces on the ground in challenging environments.

Geomorphology of aeolian dunes in the western Sahara Desert

Although the western Sahara Desert is dominated by aeolian dunes, research on the geomorphology of aeolian dunes throughout this region as a unit has been limited compared with other large deserts. In the present study, comprehensive research is conducted on the geomorphology of dunes in the western Sahara Desert based on aeolian parameters and dune growth mechanisms. We identified the controlling factors on the dune morphology and formation of superimposed dunes. The results suggest that the spatial patterns of dune morphology are closely correlated with the drift potential (DP) and dune orientation. A well-defined gradient of declining DP, resultant drift potential (RDP), and directional wind variability from north to south was found, indicating a gradual weakening trend in the DP along the sand flow path. Linear and transverse dunes are distributed on the central part of the desert. Barchan dunes are distributed on the western coastal areas and desert margins. Lastly, star dunes are distributed in the upwind on the northern desert margin. We concluded that the wind regime and sand availability directly impact the dune morphology in the western Sahara Desert by considering the growth mechanisms. This study provides valuable reference data on regional aeolian activities that can be used by subsequent regional aeolian geomorphology studies in the western Sahara Desert.

Northward shifts of Canadian late deglacial drainage routes caused a stronger and warmer Canaries Current that enabled Holocene monsoons and a savanna on the western Sahara

This paper proposes an explanation for the well-watered savanna on the presently barren western Sahara Desert during the mid-Holocene and near the ends of other earlier Canadian deglaciations. Between 7,500 and 4,000 years before present, a humidity index indicates moist conditions and a savanna in the western Sahara. During this interval, a stronger and warmer Canaries Current return flow of the Gulf Stream nullified the effect of cold water that upwells off the northwest African coast due to the westward movement of surface water by trade winds. The return flow was stronger than today because less eastward Gulf Stream flow was lost to the northward flow of the Atlantic Meridional Overturning Current. The Canaries Current was warmer than today because cold southern Canadian meltwater no longer entered the Gulf Stream, and the high latitude climate was warmer then. Similar conditions probably prevailed at the ends of many other deglaciations, which were separated by 20,000 to 70,000 years due to orbital factors and variable glaciation. The savanna connections across the Sahara would have allowed each Hominin population to evolve in the isolated Moroccan-Algerian coastal zone to extend its range into the larger Africa. The intermittent savannas could therefore have played a significant role in the evolution of the many Hominin species found in the African fossil record over the last three million years.

Direct and semi-direct radiative effect of North African dust in present and future regional climate simulations

This study explores the direct and semi-direct radiative effect of North African dust in the present and future climate using the regional climate model RegCM4. The simulations cover a historical decade extending from December 1999 to November 2009 and a future decade that spans from December 2089 to November 2099 under the Representative Concentration Pathway 4.5 (RCP4.5), without considering land-cover/land-use changes. For each time-slice a set of two experiments was conducted, namely the “Control”, in which dust is radiatively inactive and the “Feedback”, in which dust interacts with shortwave and longwave radiation. The impact of North African dust on the regional radiative balance is assessed by comparing the “Feedback” and the “Control” experiments during the historical period. The results indicate that the combined effect of dust Direct + Semi-direct Radiative Effect (DSRE) on the shortwave is − 13.8 W m−2 and − 10.7 W m−2 over the Sahel and the Sahara, respectively. The Direct Radiative Effect (DRE) dominates over the Semi-direct Radiative Effect (SRE) in both winter and summer, although during summer over some parts of the desert the SRE in the longwave spectrum accounts for almost 50% of the DSRE. Part of this is due to a noteworthy statistically significant increase of clouds that reaches values up to 3% and stretches across the eastern and western Sahara desert. Dust DSRE intensifies moderately in the future period (− 15.8 W m−2 and − 11.0 W m−2), while its spatial distribution remains the same, suggesting that the effect of climate change in the atmosphere will not alter the radiative effect of dust over North Africa considerably. When taking into account the dust radiative feedback in regional climate simulations the maximum temperature is altered by − 0.2/− 0.2 °C and − 0.3/− 0.6 °C over the Sahel and Sahara regions, respectively, during the summer/winter period, mainly as a result of changes in the shortwave radiative balance. On the contrary, the minimum temperature increases, since it is mostly controlled by the longwave radiation emitted from the Earth’s surface. In the future period the near surface air temperature increases by 1.5–2.5 °C and the fine dust column burden increases by + 4% to + 8% in comparison to the historical period, mainly due to the RCP4.5 forcing. When the dust feedback on climate is active in future simulations it can decrease the summer daily maximum temperature by 0.3 °C over Sahel, and decrease or increase it locally in Sahara by up to 0.2 °C. Prior to the Feedback-Control analysis an extensive evaluation has been conducted for dust optical depth, dust extinction, near surface air temperature and cloud fraction cover using the LIVAS, CRU and CM SAF datasets.

Projected Heat Stress Under 1.5 °C and 2 °C Global Warming Scenarios Creates Unprecedented Discomfort for Humans in West Africa

AbstractHeat and discomfort indices are applied to the multimodel ensemble mean of COordinated Regional climate Downscaling EXperiment‐Africa regional climate model projections to investigate future changes in heat stress and the proportion of human population at risk under 1.5 °C and 2 °C global warming scenarios over West Africa. The results show that heat stress of category Extreme Caution is projected to extend spatially (up to 25%) over most of the Gulf of Guinea, Sahel, and Sahara desert areas, with different regional coverage during the various seasons. Similarly, the projected seasonal proportion of human population at discomfort substantially increases to more than 50% over most of the region. In particular, in June–August over the Sahel and the western Sahara desert, new areas (15% of West Africa) where most of the population is at risk emerge. This indicates that from 50% to almost everyone over most of the Sahel countries and part of the western Sahara desert is at risk of possible heat cramp, heat exhaustion, and heat stroke in future climate scenarios. These conditions become more frequent and are accompanied by the emergence of days with dangerous heat stress category during which everyone feels discomfort and is vulnerable to a likely heat cramp and heat exhaustion. In general, all the above features are more extended and more frequent in the 2 °C than in the 1.5 °C scenario. Protective measures are thus required for outdoor workers, occupational settings in hot environments, and people engaged in strenuous activities.

Replenishing Milk Sons

AbstractSince the decolonisation period, the Sahrāwī in the western Sahara Desert, North Africa have experienced very specific sociopolitical transformations relating to their millennia-old specialisation in nomadic pastoralism. This article examines the effects of such transformations on particular forms of making kin out of others – milk kinship. Various political circumstances have obliged the Sahrāwī to restructure their customary principles of organisation, possibly diminishing these practices. I question the effects of the loss of milk kin – particularly of milk sons – and the strains on customary matrilocal relations in the survival pressure on kinship relying solely upon ‘blood’ sons to replace these ‘missing men’.

The role of Nucularia perrinii Batt. (Chenopodiaceae) in the camel-based Sahrawi social-ecological system

BackgroundPastoral social-ecological systems (SESs) are adaptive and complex systems rooted in the extensive exploitation of forage plants for livestock-based livelihoods and culture. There are species and relations that are foundational to the existence of these SESs. Nucularia perrinii Batt. (Chenopodiaceae) is an endemic halophyte plant of central and western Sahara seldom cited in the scientific literature. The objective of this study was to investigate the role of this plant in the SES of the Sahrawi camel nomads of Western Sahara.MethodsThe data analyzed were collected in the Sahrawi refugee camps of Algeria and in Western Sahara between 2006 and 2010. Fieldwork included semi-structured (n = 38) and retrospective (n = 12) interviews with Sahrawi refugees, nomads, and camel owners about N. perrinii and associated topics (e.g. distribution, importance for camels, camel diseases, associated grazing practices, other forage plants, etc.).ResultsAskaf, as the Sahrawi call the plant, is crucial to camels’ survival, providing salts and water even during dry spells. It holds a pivotal role in the Sahrawi culture, defining the geographical boundaries of the Sahrawi SES and relating the grazing territory with the taste it gives to camel milk, which support the inclusion of askaf as a main element of Sahrawi cultural identity.ConclusionsWe argue that N. perrinii ties the ecology of the western Sahara desert with camel husbandry and associated livelihoods, and further with the culture and worldview of the Sahrawi nomads. We stress the keystone role that some forage plants may have in extensive pastoral SESs worldwide.

Replenishing Milk Sons

Since the decolonisation period, the Sahrāwī in the western Sahara Desert, North Africa have experienced very specific sociopolitical transformations relating to their millennia-old specialisation in nomadic pastoralism. This article examines the effects of such transformations on particular forms of making kin out of others – milk kinship. Various political circumstances have obliged the Sahrāwī to restructure their customary principles of organisation, possibly diminishing these practices. I question the effects of the loss of milk kin – particularly of milk sons – and the strains on customary matrilocal relations in the survival pressure on kinship relying solely upon ‘blood’ sons to replace these ‘missing men’.

Elevation modelling and palaeo-environmental interpretation in the Siwa area (Egypt): Application of SAR interferometry and radargrammetry to COSMO-SkyMed imagery

Digital elevation models produced from COSMO-SkyMed imagery were used to delineate palaeo-drainage in a wide area surrounding the Siwa and Al-Jaghbub oases of the western Sahara Desert (Egypt and Libya).This new generation of synthetic aperture radar imagery is suitable for this purpose because of its high spatial resolution and capacity to penetrate dry surface sediments. Different techniques such as radar interferometry and radargrammetry were used to produce digital elevation models. These were assessed for accuracy and then combined to produce a single elevation model of the area.The resulting elevation model was used to support the geological study and palaeo-environmental interpretation of the area. It revealed buried features of the landscape, including inactive palaeo-drainage systems. Drainage features were extracted from the elevation model using geographical information systems; results were combined and assessed with respect to geological field data, as well as data from the literature. Previous studies in the area suggest that a wide river, probably the old Nile River, flowed into the Libyan palaeo-Sirte before the Late Messinian drawdown of the Mediterranean Sea. During the Late Messinian lowering of the sea the fluvial system changed shape and carved deep canyons throughout north-eastern Africa.The reported findings on the key Siwa area were used to precisely delineate the physiography of the modern drainage network and to confirm findings from our previous geological research in the area.

Dust fallout characteristics within global dust storm major trajectories

Satellite images from 2000 to 2010 were used to identify major dust trajectories within seven major deserts in the world. The fallen dust from these trajectories were collected and analyzed. The fallen dust rates tend to be lower downwind. The average samples of the world's fallen dust are negatively skewed trimodal with dominancy of silt size fractions (61 %). Most of the fallen dust within major dust trajectories is fining downwind. The fallen dust from the eastern zones (Taklimakan, Gobi, and Australian deserts) are characterized by higher percentages of feldspars and clay minerals, low carbonate content, and grain surface area in comparison to the Western zones (Sahara and Arabian deserts). The Western Sahara Desert dust is differentiated by the highest depositional rates and average quartz percentage (66 %). The dust samples in this zone contain low carbonates and grain surface area compared to dust from the Eastern Sahara Desert. The dust samples within Northern Arabia and Ethiopian-south Arabia zones show the highest average of carbonate amounts and grain surface area.

Holocene development of multiple dune generations in the northeast Rub’ al-Khali, United Arab Emirates

It has been hypothesised that in sand seas where multiple dune generations occur, each generation represents a distinct terrestrial response to contrasting palaeoatmospheric circulation conditions (Lancaster N, Kocurek G, Singhvi A, Pandey V, Deynoux M, Ghienne J-F et al. (2002) Late Pleistocene and Holocene dune activity and wind regimes in the western Sahara Desert of Mauritania. Geology 30: 991–994). However, reconstructing dunefield accumulation and preservation chronologies has often utilised a limited suite of samples because of the difficulties realised in accessing unconsolidated aeolian sands, which has limited the capacity to test this hypothesis. In the eastern United Arab Emirates, artificial excavation for quarrying and construction have generated a unique opportunity to examine and sample the internal structures of dune systems, and to generate data to test the hypothesis of dune generational development. This paper presents new data and chronologies from a multigenerational analysis of dune accumulation in the northeast dunefield of the Rub’ al-Khali. A complex developmental history during the Holocene is revealed, which does not fully conform to the notion of each dune generation forming in distinct palaeoclimatic phases, since the age ranges represented in the accumulation of secondary dunes is also found within a longer suite of accumulation ages from the underlying megaridges.

See How Much I Love You by Luis Leante, Martin Schifino

KATJAKALLIO ? "Wholly enttttainJaf...a noval that books ywin from tb* fira llae.?tba mfa lives tbe tragedy ofapeople whohm? been systematically i?niniliwd malsacrificed by history.' LUIS LEANTE I1 read the extent to which a marriage, i however long,can fall intoa shallow j habit between two people who have i barely known each other. Their con , versation and those around them has 1 consisted of irritatingly pedantic and i presumptive philosophical subjects, 1 such as thenature ofGod, as iftheir i opinions would suffice as the final 1 word in such matters, i For an observant reader, Kal j Ho's narrative is rich in symbols, the i most extraordinary ofwhich is the , explosion of a glass tabletop soon 1 after Henri's move out of the apart i ment. The table is designed by the 1 internationally famous Kaj Franck, i whose mention exemplifies current [ prose style. In it,labels and designer i names, presumed to be familiar to , readers, assume comparable impor 1 tance with narrative events and i characters. It's noteworthy that Tuu 1 likki's emotional blindness toward i Henri is offsetby Sofia's instinctive ' knowledge of Henri as a person, i The narrative is filteredthrough the , perspectives ofmany characters and i their curiously stilted lives, which , express the vulnerability of today's 1 human beings and the loss of emo tional anchors that would attach them to somethingmeaningful and lasting in life. To emphasize the fact, Kallio juxtaposes an immigrant Mus lim family, still a rare occurrence in Finnish society,having a picnic in a park. But for the father's head cover, he wears Western clothingwith the inevitable jeans. He attends to his threechildrenwhile themother sits serenely secure in her place with a soft scarf tied around her head. It occurs to Tuulikki that unlike thewomen she knows, theMuslim woman still has religion and tradi tions as her support. She embraces them as if they were rooms where every object is familiarand in itsown place, reflectingthedignity ofmany hundreds of years of culture. Thus the reader ismet with yet another instance inwhich Kallio reverses the familiarwith the unfamiliar while simultaneously jolting her readers from their comfort zones. Katja Kal lio is to be congratulated for narrat ing tous what, fora lack of a better word, we call postmodernity inboth itsweaknesses and rare triumphs. Seija Paddon Toronto Luis Leante. See How Much ILove You. = Martin Schifino, tr. London. Marion = Boyars.2009. 256 pages. ?9.99/$ 14.95.| isbn978-0-7145-3154-0| Luis Leante's enchanting, award- E winning 2009 novel, SeeHow Much I E Love You, reflectsthe misery faced in E thedesert of the Western Sahara in = the 1970swhile entangling the read- = er in a haunting love storybetween E two Spaniards who, in turn,become E involved with a dangerous and = hopeless Spanish colony inAfrica? = a place where "the scorching sun = and the dry, biting wind make it = impossible for life to go about its = business normally." Inspired by = Leante's humanitarian journey to E the area in 2005, this evocative novel E includes thenecessary historywhile E stillbeing satisfactorilyentertaining. = Eighteen-year-old Montse is = eager for adventure but confined E to her rich parents' house, and the E dashing Santiago San Roman ful- = fillsher yearning. As an optimistic = beginning forboth the couple and E the country, the two young lov- = ers become inseparable and fall = madly in love,with littleattention E to Spain's conflicts or politics. But E when Montse sees Santiago with E another girl and learns of her own E pregnancy, she vows to never speak E to him again, abandoning the rela- E tionship and driving him to mili- = taryservice in thedangerous depths = of the Western Sahara desert. San- = tiago is desperate and frustrated, = and finally forgetsMontse to find = love with a Saharawi woman living = near his base. Twenty years later, = Montse, now a brilliant but disheart- = ened doctor, is divorced, and her E only daughter has justdied. She had E heard years before thatSantiago had E been killed in battle, but coinciden- E tally she finds a photograph of him E in a patient's belongings. Her life- E January-February 2010 i67 H threatening journey to findhim in...

Late Pleistocene and Holocene dune activity and wind regimes in the western Sahara Desert of Mauritania: Comment and Reply

[Lancaster et al. (2002)][1] provide some useful information on Quaternary eolian dune activity in western Mauritania. As outlined below, however, their publication could benefit from (1) a statement regarding the relevance of their research to the debate on the age of “Ogolien” dunes in western

Late Pleistocene and Holocene dune activity and wind regimes in the western Sahara Desert of Mauritania: Comment and Reply

We appreciate Swezey's interest in our paper, but we have to disagree with his reinterpretation of our data. Swezey's statement that our data suggest that “Ogolien” dunes of western Mauritania range in age from 27–8 ka is apparently based upon the total range of all of the optically

Late Pleistocene and Holocene dune activity and wind regimes in the western Sahara Desert of Mauritania

The western Sahara Desert in Mauritania is dominated by extensive sand seas consisting largely of linear dunes. Analyses of Landsat images, geomorphic and stratigraphic studies, and optically stimulated luminescence dating of dunes in the Azefal, Agneitir, and Akchar sand seas provide evidence that three main generations of dunes were formed during the periods 25–15 ka (centered around the Last Glacial Maximum), 10–13 ka (spanning the Younger Dryas event), and after 5 ka. The wind regimes that occurred during each of these periods were significantly different, leading to the formation of dunes on three distinct superimposed trends—northeast, north-northeast, and north—and the development of the sand seas as composite geomorphic features.

Psychiatric symptoms reported by international peacekeeping personnel in the Western Sahara Desert.

Psychiatric symptoms reported by international peacekeeping personnel in the Western Sahara Desert.

A hemispheric dust storm affecting the Atlantic and Mediterranean in April 1994: Analyses, modeling, ground‐based measurements and satellite observations

One of the largest recorded dust transport events originating from the great Sahara desert during April 1994 affected the entire region extending from the Caribbean to the Eurasian continent. This hemispherical transport of airborne dust took place during a series of storms that developed during the first three weeks of April in a background of low‐index circulation. These repeated events are studied through the combined analyses and interpretation of atmospheric data, ground‐based aerosol measurements, visibility observations, AVHRR and Meteosat visible band satellite data, and the results of Eta model simulations, including an aerosol transport component. The observations produce a consistent picture of the temporal and spatial development of the dust events, whose main features are used in parts to verify the model results. The rate of dust suspension from some areas of the western Sahara desert exceeded 1.5 mg m−2 h−1 and the maximum column integrated dust load reached 2 g m−2 during April 3–5 1994, when the first major suspension event produced two simultaneous pulses of dust moving in opposite directions across the subtropical Atlantic Ocean and the eastern Mediterranean Sea. These dust suspensions were created by surface winds resulting from subsidence on the northeastern side of a blocking anticyclone in the Atlantic region and subsequent winds of an intense developing cyclone in the Mediterranean‐African region. In the following period, maximum dust loads of 4.5 and 2.5 g m−2 occurred on April 12 and 17, respectively, when new cyclones transported dust across the Mediterranean from Africa to Europe. The generation of the two dust pulses during the first even and the recurrent cyclone transport in the following period is shown to be the result of a large‐scale, anomalous atmospheric circulation connected with blocking in the Atlantic Ocean and the interactions of upper air jets downstream of the blocking. The particular state of the hemispheric circulation during the studied period corresponded to the positive phase of the North Atlantic Oscillation (NAO). While previous statistical evidence has consistently linked dust transport in the region with the NAO signatures, we show the same connection on the basis of this case study.

An empirical model for interpreting the relationship between backscattering and arid land surface roughness as seen with the SAR

The nature of the surface in a flat arid zone located in the western Sahara desert was studied and its roughness parameters defined. The main geological units were compared with backscattering data from ERS-1 images. Results showed a close correlation between the backscattering coefficient, /spl sigma//sub 0/, and the maximum height, h/sub max/, of the rocks making up the arid landscape. The simplified relationship /spl sigma//sub 0/=4.63.1og h/sub max/-15.29 (with h/sub max/ in cm and /spl sigma//sub 0/ in dB) was established from field measurements, giving an r/sup 2/ of about 88%. This empirical relationship is confirmed by another close relation between /spl sigma//sub 0/ and the statistical parameter s, the height standard deviation. The advantage of h/sub max/ is that it can be extracted for any site, whatever its roughness may be. The spatial distribution of the rock facets and the geometric characteristics of the incidence angle of the radar signal seem to explain the results.