Part Of Desert Research Articles

The geochemical characteristics of dust material and dust sources identification in northwestern China

To determine dust sources in the northwestern China, the spatial distribution of dust geochemical elements in the Hexi Corridor Desert, a total of 40 samples were collected at a height of 1.5m over sandy and gravel surfaces at six field sites. In this work, 21 trace elements and seven major oxides were analyzed. Land surface characteristics influenced the dust emission, and the percentages of transported silt, clay, silt/sand, and clay/sand at a height of 1.5m were related to gravel cover and the percentage of 0.063-mm-sized grains at the surface. The SiO2 content was the highest (mean 61.20±9.17%), whereas the K2O content was the lowest (mean 1.9±0.3%) in all field sites. For the six sites, the Ti content was the highest (mean 3247.5±502.5μg/g) and the Nb content was the lowest (mean 9.6±1.9μg/g). At all sites, Co, As, and Nd were enriched, whereas Mn, Ti, Sr, Ce, Ni, Rb, Y, P, V, Ga, and Ba were depleted. P, Ti, V, Ni, Rb, Sr, Y, Ba, and La originated from crustal sources, and Cl, Cr, Cu, and Zn were sensitive to anthropogenic activity. The main transported trace elements were Ti, Mn, Ba, P, Cl, Sr, and Zr, which accounted for >90% of the total trace elements. PCA analysis indicated that two principal components with eigenvalues>1 could be extracted from the data. The relationship between Rb/Sr and Ba/Sr and between Fe/Al, Mg/Al, and Ca/Al was used to identify dust sources. Two dust sources were identified in northwestern China: one source comprised the Badain Jaran Desert, Tengger Desert, Hexi Corridor Desert, and part of the Inner Mongolian Gobi Desert, and the other source comprised the desert adjacent to Dunhuang Gobi Desert, and part of the Inner Mongolian Gobi Desert.

GEOMATICS BASED SOIL MAPPING OF THE EASTERN DESERT PART OF SOHAG GOVERNORATE, EGYPT

The aim of this study is to apply the powerful capabilities of advanced remote sensing and GIS techniques to identify and characterize the main physiographic units of some soils of the Eastern Desert Part of Sohag Governorate. A physiographic analysis using visual interpretation of false colour composite (FCC) of Landsat ETM images was carried out to delineate the different physiographic units of the studied area which accurately defined by the Digital Elevation Model (DEM) which generated from the Shuttle Radar Topographic Mission (SRTM). Twelve soil profiles were collected and examined to represent the soils of the studied area. The soils of the studied area are slightly to highly saline (EC values ranged from 3.83 to 10.67 dS/m). Soil texture is mostly sandy to loamy sand. Soil pH values ranged from 7.83 to 8.45. Organic carbon content is very low with a maximum value of 0.35%. Regarding the CEC, it varied from 2.68 to 4.76 cmole+/kg and the CaCO3 ranged from 3.81 to 17.68 %. The soils were classified as Typic Haplocalcids, Typic Torripsamment and Typic Torriorthents. The major landforms of the studied area were described as Wadi Bottom (WB), Bajada (B), Alluvial Fans (AF), Tableland (T), Gently Undulating Sand Sheet (GUS) and Undulating Sand Sheet (US).The data revealed that current capability of soils is moderately suitable (S2), marginally suitable (S3) and temporary not suitable (N1). The major limiting factors were texture, topography and salinity. With the application of some scientific and technical improvements, the limiting factors could be mitigated to attain the potential capability of the soils of the study area.

Techno-economic Impacts Analysis of a Hybrid Grid Connected Energy System Applied for a Cattle Farm

Abstract Increase in energy demand has made the renewable resources more attractive. Representing the largest sources of renewable energy, Solar and wind systems are expanding due to the rapid depletion of fossil fuel resources and the growing evidence of the global warming phenomena. This study aims to investigate the techno-economic impacts of a hybrid grid connected PV/wind energy system applied for a medium cattle farm in the north part of Algerian desert. The target location is a medium farm of 20 dairy cows in Ghardaia city, with the total annual electrical energy consumption of 6.716kWh, and a peak demand of about 7.7 kW. The system is optimized using the National Renewable Energy Laboratory's (NREL) HOMER software according to the net present cost (NPC) value. Furthermore, three scenarios are proposed to assess the system configuration according to its impact on both technical and economic balance of the farm. It is found that under the specific climatic conditions of the studied location, the three optimized systems satisfy the typical farm load of 18kWh per day. The second scenario optimized system meets the requirement of paying back the total costs of system investment during the system's lifetime and the third scenario optimized system enhances the grid reliability by decreasing the power grid peak load by 70 kW and feeding to the grid 119MWh annually.

Sediment grain-size characteristics and its source implication in the Ningxia–Inner Mongolia sections on the upper reaches of the Yellow River

The Ningxia–Inner Mongolia (NIM) reaches of the Yellow River are characterized by a high sediment load, severe siltation, large channel migration, and frequent dike breaching, resulting in substantial social, economic, and environmental problems for residents along the river. Therefore, studies on the grain-size characteristics of sediments in the NIM reaches of the Yellow River and locating the primary sediment source areas are important for the prevention and mitigation of silt accumulation and the construction of water conservation facilities. In this study, 361 samples from the Yellow River and 178 samples from potential source areas were analyzed. Large grain sizes in the riverbed and floodplain materials were found in the desert sections and in sections containing 10 tributaries, respectively. The size of the riverbed and floodplain materials fluctuates relatively frequently in the tributary sections and is coarser at confluences of the tributaries with the Yellow River. The floodplain material is better sorted than the riverbed material, and the sorting coefficients (especially the former) fluctuate most widely in the tributaries sections. Two main fractions of the floodplain and most of the riverbed materials in the major river reaches are observed: 3.9–63μm and 63–250μm. The first fraction component of the riverbed material, 63–250μm, is found in the desert sections and part of the tributary sections, whereas the second fraction component (250–500μm) is found in some parts of the desert sections. The variations in the size characteristics of the riverbed and floodplain materials demonstrate that both materials are derived from lateral sources. The main sources of the riverbed materials are the Ulan Buh Desert and the Kubuqi Desert in the Wuhai-Zhonghexi reaches, and the main sources of the riverbed and floodplain materials are the 10 tributaries in the Zhonghexi-Lama Bay reaches. The riverbed and floodplain materials in the desert sections are deposited near the source and far from the source, respectively. Both types of sediments in the tributary sections are mainly deposited near their sources. Through wind and hydraulic sorting, the size of the riverbed material in the tributaries sections becomes finer in contrast to that in the desert sections, which suggests that coarse sediments have not been effectively carried downstream.

Baseline Study of Drinking Water Quality? A Case of Leh Town, Ladakh (J&K), India

Water is the vital resource on which life sustains and water becomes more valuable in this cold desert part of the northernmost region of India, called Ladakh which comprises of two districts, Leh and Kargil. Groundwater since ancient times in the form of springs provided ample water for the region and its contribution has increased manifold in the wake of recent spurt in bore well installations, especially, in Leh-Town. Due to increasing urbanization, with surge in a huge floating population in the absence of a sewerage link in summer tourism boom season, puts extra stress on the limited water resources of the area and with the rising living standards, grey and black water is being disposed off in the ground-pit or in septic tanks without any treatment. This may lead to pollution of groundwater resources especially, in the densely populated residential areas. For insuring sustainable development of groundwater, in the absence of any observation wells for constant monitoring of quality or quantity of groundwater and the unregulated installation of bore-wells makes this quality characterization very significant and helps in future management. The physico-chemical parameters like pH, electrical conductivity, turbidity, total dissolved solids, hardness, alkalinity, nitrates, fluoride, and chlorides were analyzed to meet the objective of the study. The results revealed that in general, the present status of groundwater quality is suitable for drinking purposes and out of 20 total samples evaluated, 75% of samples had NTU above desirable limit while 10% samples each recorded TDS and EC above desirable limits.

PEDOLOGICAL STUDIES AND TREATED WASTEWATER REUSE FOR TIMBER TREES PRODUCTION IN EGYPT- EAST NEW CAIRO CITY

The present investigation soils located at desert part of east New Cairo City , south of El Kattamia –El Ain El –Sokhna new high way . The area under consideration have three physiographic units: Soil of fans and outwash plain which have three soil map units i.e. calcareous moderately deep and deepsoils, gypsiferous moderately deep to deep soils and calcigypsids moderately deep soils. Miscellaneous (Rock Soils) appear three soil map units i.e. calcareous shallow and very shallow soils, gypsiferous shallow and very shallow soils and calcigypsids shallow and very shallow soils. Miscellaneous (Rock land). The soils are classified to family level according to USDA, 2010. Current suitability study shows that soils under consideration have marginal level (S3) except soil profiles l and 6 which have moderately suitable level (S2) while soil profile 11 appear not suitable class (N1). The potential suitability was moderately suitable (S2) except soil profiles 5,7,8,10 and 11 and have marginal level (S3), while soils profile 6 has highly suitable class (S1). Concerning the available Fe, Mn, Zn, and Cu in soil are ranged between low to adequate except extractable Cu of calcigypsids soils have high level. Treats sewage water have different limitation , so, it must be used in special cases like timber trees and drip irrigation or improved surface irrigation system is suggested system for irrigation.

LAND SUITABILITY EVALUATION OF WADI EL ASSIUTY AREA, EASTERN DESERT OF ASSIUT GOVERNORATE, EGYPT, USING REMOTE SENSING DATA

The study area is located in the Eastern desert part of the Nile valley ofAssiut Governorate, and covers about 56670 feddans. The objective of this studyis to evaluate the soils of Wadi El Assiuty for the agricultural development usingremote sensing data. The obtained physiographic units in the study area and theassociated soils that represented by ten soil profiles were attributed as:(1) Gently undulating to undulating oldest alluvial terraces which include the taxonomicunits of Typic Clacigypsids, loamy-skeletal, mixed, hyperthermic as dominated soils,and Typic Clacigypsids, coarse-loamy, gypsic, hyperthermic, as minor soils.(2) Almost flat to gently undulating old alluvial terraces have the taxonomic units ofTypic Haplocalcids, sandy-skeletal, mixed, hyperthermic as dominant soils, whileTypic Clacigypsids, coarse-loamy, mixed,hyperthermic, as minor soils.(3) Young alluvial terraces includes Typic Haplocalcids, sandy, mixed, hyperthermic asdominant soils.(4) Wadi bottoms includes the taxonomic units of Typic Torriorthents, sandy-skeletal,mixed, hyperthermic and Typic Torriorthents, sandy, mixed, hyperthermic.(5) Dissected Rockland which are not promising area for the agricultural land use.The current and potential suitability of the studied soils for irrigatedagriculture were estimated. The obtained results indicate that all soils inits present condition have no to slight intensity of limitations for wetness,soil depth, calcium carbonate and gypsum contents. The soil textureincluding gravel, salinity and alkalinity, and soil topography are the mosteffected soil limitations. The obtained current suitability classes aredominated by the marginally suitable one (S3), with exception thecurrently not suitable (N1) of the oldest terraces soils. All the studied soilprofiles can be potentially classified as moderately suitable (S2), whichrefers to its suitability after major soil improvements.

Climatic-Adaptability Solution in Traditional Architectural of Desert Areas of Iran/Kashan

Nowadays, the shortages of fossil based energy on the earth and the pollution caused by using them is a noticeable problem that people are challenging with. As a result, human try to use natural resources vastly instead of fossil-based ones to reduce their consumption dramatically. In this circumstance, the role of architects are more important than ever in reducing the need for energy by proper designing likewise the past construction history. Green building design criteria emphasizes the energy-efficient performance of fenestration materials. Iran is a country comprising of four main different climatic areas. Selecting materials and using proper techniques for a building project is a challenging task in each part. Ancient buildings were built by different materials, techniques and forms in different parts of this country. One of the main parts of climatic areas in Iran is the hot and dry climates such as deserts. The appropriate materials and techniques which were used in ancient buildings in this part of the country to make this area comfortable for people will be investigated in this paper. Moreover, the buildings of Kashan, located in the desert part of Iran, will be mentioned as case study.

Magnitude, Distribution and Associated Socio-behavioral Risk Factors of Coronary Artery Disease: A Hospital Based Study from Desert Ecology in India

Coronary artery disease is among the leading causes of deaths and disease adjusted life years lost world wide. This is an emerging health threat in India too. Government of India has recently launched a pilot programme for prevention and control of non-communicable diseases. There is paucity of information on this disease in desert part of Rajasthan, India. Study aims to provide the initial baseline information on occurrence of this disease in district Jodhpur of Thar desert, India; an area unexplored hitherto. Retrospective descriptive epidemiological study was conducted at a tertiary care hospital in Jodhpur. There were 15.589 new patients admitted in hospital per 100000 populations in year 2001 for district Jodhpur. The mortality rate was 152 deaths/1000 admitted patients for year 2001. Proportion of patients who died below 50 years of age was 11.91% and acute myocardial infarction cases <40 years of age was 6.88%. Consecutive years have shown increasing trend in number of patients admitted each year with major share of patients by acute myocardial infarction and deaths caused by this. There was significantly higher proportion of female (p<0.05). Lack of information on socio-behavioural risk factors was major limitation. Coronary artery disease is an emerging problem in district Jodhpur. Patients with advanced stage of disease are reaching to the hospital with poor treatment outcome. Awareness exercises and prospective study on risk factors of coronary artery disease is required in this setting.

Life on an Edge among the Changpas of Changthang, Ladakh

The Buddhist Changpas-pastoral nomads of Changthang, Ladakh form an ethnic entity. Like other nomads in the world, the pastoral nomads of Changthang are a minority, suffering problems of under representation, social, economic and geographic marginalisation. The region is extremely poor in conventional energy sources (fossils, fuel and wood) and has almost no industrially exploitable resources. Natural environmental limitations dictate many aspects of traditional life, especially settlement pattern and economic system. Among the Changpas, the pastoral mode of livelihood is an evident attempt to adapt to a natural environment, which provides no plants as food that can support humans and has no potential for growing food crops. Under such conditions, the only solution is to domesticate large herds of various animals, which can feed off the plants and in return, the animals can sustain humans. Since, the ecological conditions of Changthang are not favourable for crop growing, the Changpas raise large herds of sheep and goats as well as transport animals like yaks and horses. These animals provide the Changpas with meat, milk, varieties of wool, which they use themselves and barter for grains and other utilities. This economic interdependence of nomadic pastoral and settled population has been an important characteristic of the society in this area. The Changpas social behaviour is, in part, a response to constraints and opportunities of the natural environment. Both stability and change are outcomes of response to the immediateneeds of daily life. The basic form of social organisation in the area was rural, and social relations among the agriculturalists, nomadic and semi-nomadic groups were based on trade and exchange of essential commodities. The Changpas’ subsistence level pastoral economy, traditional social and religio-cultural systems are composite part of cold desert’s ecological system. Their way of life shows a capacity to adapt themselves to the rugged cold desert environment. The Changpas possess a high degree of specialised knowledge and a flexible social organisation to make viable the mobile mode of production. Despite the ecological constraints, the Changpas were managing their environment for making a living without outside intervention. Their own societal controls like polyandry and cutting of excess animals, helped in turn by their customary rights and equity in resource allocation has helped them. The Changpas are organised using a patrilineal idiom, all members being patrilineal descendants of the founding ancestor. Rangeland, livestock, manpower and the considerable knowledge of the skills necessary to exploit them effectively are the principle economic resources of the Changpas of Changthang. Resource management in a risky environment illustrates the skills of the Changpas for survival. Traditional practices of Changpas, such as the rotation of grazing areas and use of reserve pastures in case of natural calamities help manage the variability of ecosystem and bail out pastures from a state of permanent degradation. Each animal has its own specific characteristics and adaptation to the environment. Rearing together different animals maximised the use of vegetation in the pasture. Different animals graze on different plants. In recent decades, the Changpas of Changthang have been experiencing changes due to external pressures that have altered political, economic and social landscapes. Traditionally, the Changpas were self-sufficient and livestock were providing them with their food and lodging. In recent decades, continuous massive defense investments and improvement in communications; proliferation of government departments; introduction of development plans; provision for basic amenities, alterations in traditional subsistence economy, its commercialisation and extension of know-how through government departments and non-government organisations and tourism has led to a higher motivation among local people for better standards of living. Increasing administrative and market integration and population growth over the years have weakened socio-homeostasis with no functional substitutes for restoring positive social system. For centuries, pastoralists in Changthang have lived in the context of environmental uncertainty and have developed a diverse range of strategies, institutions and network to minimise this unpredict-ability and risk. Pastoral management strategies, which may have worked previously, may or may not be sufficient now. The three communities of Samad, Korzok and Kharnak responded differently to these changes. Various pressures with an ever-increasing rate of change necessitated the adoption of new strategies for survival.

Aeolian transport in the field: A comparison of the effects of different surface treatments

Aeolian transport represents the result of wind–surface interactions, and therefore depends strongly on variations in the characteristics of the sediment surface. We conducted field observations of aeolian transport of typical dune sand in three 80 m × 80 m plots with different surface treatments: gravel‐covered sand, enclosed shifting sand, and open (unprotected) shifting sand. The study was performed at the Shapotou Aeolian Experiment Site in the southeastern part of China's Tengger Desert to compare the effects of these different surface treatments on aeolian transport. To do so, we analyzed the flux density profiles and transport rates above each surface. The flux density profiles for all three treatments followed the exponential decay law that was proposed by most previous researchers to describe the saltation flux density profiles. Coefficients of the exponential decay function were defined as a function of the surface and the wind velocity. The enclosed and open plots with shifting sand had similar flux density profiles, but the flux density above gravel‐covered plots showed that transport decayed more slowly with increasing height, producing flux density profiles with a higher average saltation height. The transport rate above the three treatment plots tended to increase proportionally with the cube of the mean wind velocity and with the maximum wind velocity during the observation period, but was more strongly correlated with the square of drift potential. Transport rates above the plot with open shifting sand were greater than those above the plots with enclosed shifting sand and the gravel‐covered plot.

Changes in glucose-6-phosphate dehydrogenase activity in Indian desert malaria vector Anopheles stephensi during aging

Malaria parasite requires a specific time to replicate and disseminate in the mosquito's body before transmission to naïve hosts can occur. Vector control has a proven record in the prevention and control of malaria. The evaluation of vector control strategies requires accurate methods of predicting mosquito age. Anopheles stephensi is the principal malaria vector of the desert part of India. The objective of this study was to correlate the age of laboratory reared and field collected adults of An. stephensi with the glucose-6-phosphate dehydrogenase (g6pd) activity. The measurement of g6pd activity was carried out in a UV–vis spectrophotometer. The g6pd activity in the males and females An. stephensi was inversely proportional to their age. A significant correlation of the g6pd activity was recorded between the field collected and laboratory reared mosquitoes. The g6pd activity in the males An. stephensi was found to be significantly higher than the females. The finding of the present study is useful for the prediction of the age of males and females An. stephensi.

Point irrigation design for experimental field in northern part of Gobi desert in Mongolia

The present paper focuses on the point irrigation design for crops and growing vegetables on an experimental area 2432 m&lt;sup&gt;2&lt;/sup&gt; at Buchel locality, Northern part of Gobi desert in Mongolia. An underground water source (drill hole &amp;ndash; well capacity 2 l/s with water temperature 10&amp;deg;C) and electricity were available in the locality of the selected area of 1 ha and 0.2% grade of slope (no map was available). The design of the surface and subsurface point irrigation for an area of 128 m&lt;sup&gt;2&lt;/sup&gt; is shown together with a brief description of the hydraulic materials used for the development of the original HYBOZAM program, which was programmed in Microsoft Excel editor, especially to design the pipe dimensions of the point irrigation. A combination of two plastic pipes (with diameters 35.4/40 mm and 28.2/32 mm and 20 m lengths each) was used to provide suitable irrigation uniformity from the orifices on the laterals. HYBOZAM program provides a visual evaluation of the discharge distribution uniformity from the orifices on the laterals by its graphical output. An example of Z1 lateral for surface point irrigation (variant 2) is presented. The final result of the design calculation is given in the table presenting the most important outputs, including statistic evaluation of the discharge distribution uniformity. A table is presented for surface point irrigation &amp;ndash; variant 2. From the table is it clear that hydraulic requirements as well as discharge distribution uniformity from the orifices on the laterals have been fulfilled. &amp;nbsp;

Complex study of characteristics of a Cb cloud developing over the arabian peninsula under conditions of high dew point deficit in the atmosphere. Part 2. Analysis of the meteosat data

Development of a long-living Cb cloud in the desert part of Saudi Arabia on April 10, 2008 is analyzed. Continuous satellite and radar observations of the cloud are carried out during five hours. Numerical modeling of the cloud is performed using a nonstationary 1.5-dimensional model. Data on the Cb cloud and its anvil development dynamics are obtained. It is shown that the anvil characteristics differ significantly in the zone of its formation directly over the cloud and when moving away from it. It is pointed out that the radar underestimates the anvil sizes. Estimation of precipitation rate from the cloud under study by means of satellite and radar measurements is compared against the results of numerical modeling. It is found that precipitation rate could reach 100 mm/h. The radar estimates of the precipitation rate are significantly overstated, which is, in this case, due to presence of large hail particles.

“Raked” linear dunes in the Kumtagh Desert, China

Linear dunes are extensive in sand seas and dune fields around the world, but they take a range of forms due to the complex factors that control their development. “Raked” linear dunes, composed of primary ridges and subsidiary ridges that lie almost perpendicular to the primary ridges, were recently identified in the northern part of China's Kumtagh Desert. The primary ridges are typical linear dunes, but the subsidiary ridges display vestiges of barchan dunes. The subsidiary ridges are sufficiently short that they do not greatly affect the general appearance of the linear dunes. However, the raked linear dunes in the Kumtagh Desert have several unique characteristics that distinguish them from typical linear dunes. These dunes develop in an environment that is deficient in available sediment, and under a wind regime typical of linear dunes: an environment with a high wind energy and a directional variability index (RDP/DP) around 0.5. The raked linear dunes appear to have evolved from barchans following a modified form of Tsoar's (1984) model. Barchans formed under a northern wind regime were modified by an eastern wind regime oriented at an oblique angle to the barchans. The strengths of the two wind regimes are similar. Under these conditions, the barchans became reoriented, with the limbs farthest from the eastern winds extending to form subsidiary ridges and the limbs closest to the eastern winds forming the primary ridges, which appear to form mainly from dune collisions.

Behavior of square footing on dune sand reinforced with nylon fiber

Dune sand covers a large part of the world's desert. It is uniformly graded fine sand deposited by wind action. Geotechnical engineers face various problems in dealing with such soils as it has poor bearing capacity, high permeability and low shear strength etc. Reinforcing the soil with randomly distributed discrete fibers increases the shear strength of granular soil. The present paper deals with the laboratory tests on the use of nylon fibers as a means to enhance the bearing capacity of dune sand. A series of load tests were conducted on a mixture of dune sand and nylon fiber to determine various factors which influence the bearing capacity of dune sand nylon fiber mixtures. The amount of nylon fiber, added to dune sand, as 0.5%, 1.0%, 1.5% and 2%. The size of square footing and depth up to which nylon fiber were mixed varied and the load settlement behavior of square footings on dune sand reinforced with nylon fiber were recorded. The results of settlement behavior were interpreted with bearing capacity characteristics, bearing capacity ratio, settlement characteristics at constant load intensity and load intensity at constant settlement. The ultimate bearing capacity of dune sand reinforced with nylon fiber increases with nylon fiber content. Also, the ultimate bearing capacity increases with <i>H/B</i> ratio, where <i>H</i> is height of reinforced soil and B is the width of square footing.

A Water Temple at Bir Abu Safa (Eastern Desert)

L. M. A. Linant de Bellefonds briefly noted temple cut into mountainside that he saw in March 1832 in the southern part of Egypt's Eastern Desert (figs. 1-3). * On his map of the same region, he shows the temple (Eau et Temple) at the confluence of Wadis Na'am and Hodein, nearly 20 km east of its actual location at Bir Abu Safa.2 The temple is farther up Wadi Hodein, where Bellefonds' map marks only well or spring (Eau). When the authors saw no or even water source, where Bellefonds' map indicated these would be found, inquiries made of local Bisharii Bedouin led them to the correct site. When the authors compared the actual appearance of the temple with Bellefonds' drawing (fig. 3), it was clear that the two were one and the same monument. Other early desert travelers noted the temple, but had little to add to Bellefonds' description. These include Col. Purdy's observations based on late nineteenth century trip he made to the area.3 Later, G. Darresy cited Purdy and provided sketch map of the area.4 E. A. Floyer also noted the temple as a carved portal with an obliterated Greek inscription.5 Subsequently, W. F. Hume also described the temple.6 The temple is carved into the lower southern face of large sandstone mountain, which forms the northern side of narrow wadi that is branch of Wadi Hodein, and is located at 23? 18.08' N/34? 47.68' E. Bellefonds believed that the temple was stop for hunters in the region,7 but he does not elaborate. The Ptolemaic-early Roman fort at Abraq is about 13 km due north in straight line, and about 22 km via Wadis Hodein and Abraq. Along the route between Abraq and Bir Abu Safa are remains of graves, cairns, rock graffiti (including some in Arabic) and Roman-period pottery (espe cially at 23? 18.45' N/34? 48.94' E) that attest the presence of long-used track between Abraq and Bir Abu Safa.

Simulation of hydrologic changes associated with global warming

Using the results obtained from a coupled ocean‐atmosphere‐land model with medium computational resolution, we investigated how the hydrology of the continents changes in response to the combined increases of greenhouse gases and sulfate aerosols in the atmosphere, which are determined based upon the IS92a scenario. In order to extract the forced response from natural, internal variability, the difference between the mean of an eight‐member ensemble of numerical experiments and a control experiment are used for the present analysis. The global mean surface air temperature of the coupled model increases by about 2.3°C above the preindustrial level by the middle of the 21st century. Accompanying the warming, the global mean rates of both precipitation and evaporation increase by 5.2%, yielding the average increase in the rate of runoff by approximately 7.3%. The increase in the rate of runoff simulated by the model is particularly large in high northern latitudes, where the runoff from some rivers such as the Mackenzie and Ob′ may increase by as much as 20%. Runoff from many European rivers increases by more than 20%. Runoff also increases substantially in some tropical rivers such as the Amazon and Ganges. However, the percentage changes in simulated runoff from many other tropical rivers and middle latitude rivers are smaller with both positive and negative signs. In middle and high latitudes in the Northern Hemisphere, soil moisture tends to decrease in summer, whereas it increases in winter. However, in many semi‐arid regions in subtropical and middle latitudes, soil moisture is reduced during most of a year. These semi‐arid regions include the southwestern part of North America, the northeastern part of China in the Northern Hemisphere, and the region in the vicinity of the Kalahari Desert and southern part of Australia in the Southern Hemisphere. Since a semi‐arid region usually surrounds a desert, the reduction of soil moisture in such a region often results in the expansion of the desert. Soil moisture is also reduced during the dry season in many semi‐arid regions. For example, it is reduced in the savannahs of Africa and South America during winter and early spring in the Southern Hemisphere. In the Northern Hemisphere, it is reduced at the Mediterranean coast of Europe in summer.

The precipitation infiltration and runoff recharging experiment observation in the Taklimakan Desert

This is a certain quantity of available groundwater resources in the form of freshwater lens according to the survey and drilling experiment along the oil-transporting highway in the Taklimakan Desert, which is the second largest moving desert in the world, located in the northwest part of China. As the primary freshwater sources, local precipitation in the heartland of Taklimakan Desert, not only forms the runoff on the clayey ground, but also feeds the groundwater. After the analysis of historic records of the rainfall and the formation of clayey sediments, the precipitation infiltration and runoff recharging experiment was conducted, a natural rainfall-runoff process was observed and recorded. The studied area referred to this paper is located in the middle part of the desert, within 6 km wide and 60 km long along the new oil-transporting highway. This paper reveals that in the center of the desert an event of storm (4 mm) can be considered as the critical value of the runoff produced on the clayey ground. The rainfall infiltration coefficients on the sand dunes are over 0.46 for the erosion side, thus, rainstorms and runoffs as main fresh water sources feed the ground water directly.

Field Validation of Soil Solute Profiles in Irrigated Cotton

AbstractManagement of water and fertilizer N are important aspects of cotton production in the desert Southwest. GOSSYM, a cotton growth simulation model, has been used extensively to manage these inputs. Our objectives were to further validate GOSSYM by comparing model‐simulated and measured soil NO‐3‐N profiles, to evaluate GOSSYM's potential as a management tool under irrigated growing conditions in the desert part of the U.S. Cotton Belt, and to address questions about the way GOSSYM simulates NO‐3‐N movement through the soil profile in relation to irrigation water management (which in turn affects prediction of plant growth and development). We compared measured profiles of NO‐3‐N with GOSSYM‐simulated profiles. Soil profile samples were obtained from an existing N‐management field study, a split‐plot within a randomized complete block design. Mainplots were upland and pima cotton (G. hirsutum L. cv. DPL 5415 and G. barbadense L. cv. Pima S‐7, respectively). Subplots were a check (0 fertilizer N) and three other N‐management strategies. The cotton was grown on a Casa Grande sandy loam [fine‐loamy, mixed, hyperthermic Typic Natrargid (reclaimed)] near Maricopa, AZ, in 1994 and 1995. Fertilizer N rates ranged from 0 to 350 kg ha−1 in 1994 and 0 to 392 kg ha−1 in 1995. Soil samples taken to a depth of 120 cm in 30‐cm increments were analyzed for NO‐3‐N. Comparisons of simulated and actual NO‐3‐N profiles revealed tendencies in GOSSYM to overestimate NO‐3‐N leaching out of the effective rooting zone, resulting in simulated N stresses midseason. When GOSSYM simulated an N stress, between 50 and 75% of the simulated soil NO‐3‐N values were greater than the measured values, yet the simulated N stress still occurred. This indicates possible limitations in GOSSYM's ability to adequately predict N uptake by plants. The dynamic soil N portion of the model needs further refinement, particularly for cotton production under irrigated desert conditions.