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1
Yan, Zhengang, Fuqin Hou, and Fujiang Hou. "Energy Balances and Greenhouse Gas Emissions of Agriculture in the Shihezi Oasis of China." Atmosphere 11, no. 8 (July 24, 2020): 781. http://dx.doi.org/10.3390/atmos11080781.
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The objective of this study was to evaluate the difference of crop and livestock products regarding energy balances, greenhouse gas (GHG) emissions, carbon economic efficiency, and water use efficiency using a life cycle assessment (LCA) methodology on farms in three sub-oases within the Shihezi Oasis of China. The three sub-oases were selected within the Gobi Desert, at Shizongchang (SZC), Xiayedi (XYD), and Mosuowan (MSW), to represent the various local oasis types: i. Oasis; ii. overlapping oasis-desert; and iii. Gobi oasis. The results indicated that crop production in XYD Oasis had higher energy balances (221.47 GJ/ha), and a net energy ratio (5.39), than in the other two oases (p < 0.01). The production of 1 kg CW of sheep in XYD Oasis resulted in significantly higher energy balances (18.31 MJ/kg CW), and an energy ratio (2.21), than in the other two oases (p < 0.01). The water use efficiency of crop production in the SZC Oasis was lower than that of the XYD and MSW oases (p < 0.05). Alfalfa production generated the lowest CO2-eq emissions (8.09 Mg CO2-eq/ha. year) and had the highest water use efficiency (45.82 MJ/m3). Alfalfa (1.18 ¥/kg CO2-eq) and maize (1.14 ¥/kg CO2-eq) had a higher carbon economic efficiency than other crops (p < 0.01). The main sources of GHG emissions for crop production were fertilizer and irrigation. The structural equation modelling (SEM) of agricultural systems in the Shihezi Oasis showed that the livestock category significantly influenced the economic income, energy, and carbon balances.
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Selmi, Slaheddine, Thierry Boulinier, and Robert Barbault. "Richness and Composition of Oasis Bird Communities: Spatial Issues and Species–Area Relationships." Auk 119, no. 2 (April 1, 2002): 533–39. http://dx.doi.org/10.1093/auk/119.2.533.
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Abstract We used data on breeding bird communities of the oases of southern Tunisia to investigate variation in species richness and composition among local communities in relation to spatial configuration of the oasis system and to assess significance of the relationship between oasis size and local richness. Oases could be grouped into three regional systems, namely littoral, saharan, and mountainous oases. We found that at the scale of the entire oasis system, species richness and species composition exhibited significant spatial autocorrelation. That result was consistent with our prediction that the particular spatial organization of oases may have led to regional differences in availability of potential colonizers and that higher species exchange within oasis zones than among oasis zones may have played an important role in shaping local communities. With regard to the species–area relationship, we thus found that a model accounting for spatial covariance was more parsimonious than a standard regression model not incorporating information on the spatial location of oases. Overall, oasis size was a good predictor of species richness, but results were sensitive to spatial scale at which the relationship was examined. Aside from oceanic islands and forest patches, oases may constitute interesting systems to study how regional processes affect local diversity.
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Li, Bofei, Dongwei Gui, Dongping Xue, Yunfei Liu, Zeeshan Ahmed, and Jiaqiang Lei. "Analysis of the Expansion Characteristics and Carrying Capacity of Oasis Farmland in Northwestern China in Recent 40 Years." Agronomy 12, no. 10 (October 9, 2022): 2448. http://dx.doi.org/10.3390/agronomy12102448.
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An oasis is a unique landscape that fuels human subsistence and socioeconomic development in the desert ecosystem. However, the overexpansion of oases, especially farmlands, poses severe threats to available land and water resources. This study aims to assess the expansion levels, carrying capacity dynamics, and planting structure optimization to maximize economic returns in northwest China’s five Typical Oasis Groups (5TOGs) using uniform data sources, time scales, and methods. Satellite products and a water-heat balance model were used to evaluate the changes in the area and carrying capacity dynamics of the 5TOGs. A linear programming approach was used to optimize each oasis’s cropping structure for the carrying level scenario. The results showed that the area of 5TOGs has expanded from 1980–2020, and the increment of oasis farmland is the main driver of oasis expansion. The most dramatic expansion of oases and their farmlands occurred during 2010–2020. As a consequence, the carrying capacity of each oasis is deteriorating with this expansion. The additional water resources to support this expansion of the oases and their farmlands come from groundwater, which is declining rapidly. Based on the optimized planting structure, cotton remains the main crop in Xinjiang oases with more than 60% area, the cotton area should be reduced in the Hotan River Oases, and the planting structure of the Heihe River Oasis will remain unchanged. The findings of this study have provided a quantitative analysis of oasis expansion and planting structure optimization, which have practical implications for water resource management and sustainable development of agriculture to maintain the stability of the oasis ecosystem.
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Wang, Yuxuan, Yinhuan Ao, and Zhaoguo Li. "Evapotranspiration Characteristics of Different Oases and Effects of Human Activities on Evapotranspiration in Heihe River Basin." Remote Sensing 14, no. 24 (December 11, 2022): 6283. http://dx.doi.org/10.3390/rs14246283.
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Evapotranspiration plays a decisive role in the whole oasis ecosystem and is an important factor to maintain the ecological stability of oases. To quantitatively analyze the evapotranspiration differences of oases at different scales and the expansion of urbanization, it is necessary to compare and discuss them at different time scales. In this study, the spatial and temporal characteristics of evapotranspiration of Zhangye Oasis, Jinta Oasis, and Ejina Oasis in the Heihe River basin were analyzed by using the remote sensing dataset of daily surface evapotranspiration of 100 m resolution from 2010 to 2016. The difference in evapotranspiration intensity in different oases was analyzed, and the influences of irrigation and urbanization expansion on evapotranspiration were discussed. The conclusion is as follows: Zhangye Oasis is the largest oasis in the area and, compared with other oases, due to the largest proportion of wetland and farmland in the underlying surface, the intensity of evapotranspiration is also the largest, reaching 650 mm/year on average. There is no obvious annual change; the range of evapotranspiration changes fluctuates between positive and negative 60 mm/year. Jinta Oasis began to decline after 2012; the evapotranspiration value dropped from 620 mm/tear to 560 mm/year, while Ejina Oasis showed a slight increase after 2014. In the irrigation stage, the evapotranspiration intensity increased significantly. Especially in the peak season of crop growth, the evapotranspiration after irrigation increased by 4 mm/day compared with that before irrigation. The evapotranspiration in urban and oasis areas is different in summer: compare that of 2010 with 2016—the evapotranspiration intensity of the expanding towns in the northeast direction decreased by about 50 mm/month, the northwest expanding towns decreased by about 110 mm/month. There was no obvious annual change in evapotranspiration in the urban area. With the expansion of urbanization, the evapotranspiration intensity in oases decreased. The results of this study provide some reference for the study of oasis irrigation activities and urbanization expansion.
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Ye, Zhaoxia, Aihong Fu, Shuhua Zhang, and Yuhai Yang. "Suitable Scale of an Oasis in Different Scenarios in an Arid Region of China: A Case Study of the Ejina Oasis." Sustainability 12, no. 7 (March 25, 2020): 2583. http://dx.doi.org/10.3390/su12072583.
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The main objective of this work is to calculate the suitable scale of the Ejina Oasis in different scenarios (high-, normal-, and low-flow years), assess the stability of the Ejina Oasis, and, finally, accurately determine if an artificial oasis area and total oasis area need to be reduced or increased. Using the water balance method, we calculated the suitable scale of the artificial Ejina Oasis as 767.80, 624.00, and 451.33 km2 in high-, normal-, and low-flow years, respectively. By utilizing the water-heat balance method combined with an assessment of the present stability of the Ejina Oasis, the results showed that in high-flow years, the suitable scale of the Ejina Oasis is 1174–1762 km2, and the stability index of the current oasis is 0.55. In normal-flow years, the suitable scale of the Ejina Oasis is found to be 915–1373 km2, and the stability index of the current oasis is 0.43. In low-flow years, the suitable scale of the Ejina Oasis is 590–885 km2, and the stability index of the current oasis decreases to 0.27. In order to further improve the stability of oases, it remains necessary to control the scale of oases to cope with water resource shortages that result from water resource instability under climate change. The present study’s findings will enable optimal water-use planning decisions that take social, economic, and ecological issues into account, and provide the foundation for optimal decision-making for regional administrative departments to effectively coordinate regional economic development, farmland protection, environmental protection, and water resource protection.
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Matallah, Mohamed Elhadi, Djamel Alkama, Atef Ahriz, and Shady Attia. "Assessment of the Outdoor Thermal Comfort in Oases Settlements." Atmosphere 11, no. 2 (February 10, 2020): 185. http://dx.doi.org/10.3390/atmos11020185.
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Oases throughout the world have become important ecosystems to replenish food and water supplies. The Saharan Oases exist above the largest underground water supplies in the World. In North Africa, oases witness significantly growing populations in the oasis towns and receive thousands of tourists yearly. In oasis settlements, the majority of the population spends most of the time outdoors, in extremely hot conditions; however, few studies have investigated urban outdoor thermal comfort conditions. Therefore, this study aimed to assess thermal comfort in the Tolga Oasis Complex and test the validity of the ‘oasis effect’ concept. The methodology is based on comparative field measurement and calculation approaches in the heart of Tolga Palm Grove and in different urban settlements. Results indicate highest heat stress levels (Physiologically Equivalent Temperature (PET) index) in the oases Palm Grove in July, PET = 41.7 °C, and urban settlements, PET = 40.9 °C. Despite the significant difference between the old and new settlement fabrics, our measurements and calculation did not identify any noticeable variation of thermal comfort. Thus, the oasis effect on the outdoor thermal comfort was insignificant (during July and August 2018). Finally, the study discusses ways to improve outdoor spaces design and relieve heat stress in the settlements of Tolga.
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Toshboev, Zafarjon Makhramkulovich. "Geographic Distribution of Oases in Arid Regions." Journal of Geography and Natural Resources 01, no. 01 (May 19, 2021): 1–7. http://dx.doi.org/10.37547/jgnr-01-01.
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This article examines the oases that appeared on the inhabited continents of the planet. Historically, in the desert regions formed two main types of irrigated agriculture - small oasis and large oasis. Small oasis farming as a geographical type is developed in the vicinity of small water sources (small streams, streams, springs) in the foothills and in areas where deserts are flooded, groundwater leaks, temporarily adjacent to runoff. The fields of different sizes within the oases made them look like dry sheets, while at the same time showing property and legal inequality.
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Zhang, Xifeng, Yifan Zhang, Jinghui Qi, and Qiang Wang. "Evaluation of the Stability and Suitable Scale of an Oasis Irrigation District in Northwest China." Water 12, no. 10 (October 13, 2020): 2837. http://dx.doi.org/10.3390/w12102837.
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Oases support human activities in arid and semiarid regions, and their stability is important for regional sustainable development and water resource management. Water consumption is the major factor affecting the stability of oases. On the basis of remote sensing images, evaporation and socioeconomic data, this study first evaluates the stability of the Dunhuang Oasis against the expansion of an oasis irrigation district and planting structure changes from 1987 to 2015. Next, it calculates a suitable area of the oasis irrigation district using water–energy balance theory. The results are as follows: (1) During the 1987–2015 period, with the expansion in the oasis irrigation area, the planting structure underwent a marked transformation from food crops to cash crops to orchards. Water consumption pattern likewise changed considerably. (2) The stability of the Dunhuang Oasis continued to weaken from 0.54 in 1987 until it reached a dangerously unstable level of 0.17 in 2010. With the implementation of water-saving measures and a water-transfer project, the stability of the Dunhuang Oasis irrigation district increased to a metastable level of 0.22 in 2015. (3) Setting the stability are 0.5 of a stable level and 0.75 of an extremely stable level, and the oasis irrigation district should be impractical and reduced by 168 and 241 km2 to attain a suitable oasis ecosystem scale. Hence, at present, the water-transfer project is the most practical way to increase allocated water resource to the oasis irrigation district for improving its stability.
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Rezzoug, Cherif. "The impact of using modern irrigation techniques on the ancient Mougheul palm grove, South-West of Algeria." Journal of Water and Land Development 40, no. 1 (March 1, 2019): 97–102. http://dx.doi.org/10.2478/jwld-2019-0010.
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Abstract To resist against a hostile environment, the oases of Saoura developed ingenious techniques of catchment and sharing of water to exploit the rare and precious waters of the groundwater. But the intervention of modern irrigation techniques has disrupted the entire oasis system inside the oasis such as the spring, the palm grove and the ksar. These techniques have overexploited the groundwater supplying the palm grove in terms of quantity and quality. For centuries, the oases of Mougheul used only the source (with a flow of 25 dm3∙s−1 in 2001) which is inside the oasis to irrigate the parcels and herds. After the year 2005, the state decided to supply the city of Bechar with drinking water through the catchment field of Mougheul through five modern boreholes, which had a profound impact on the oasis, its surroundings, and the whole artesian source. In this work, we study the impact of the use of modern catchment systems on the water source and the life of the Mougheul population. By interviewing farmers and landowners about the impact of groundwater scarcity on the oasis. This allowed knowing the current state of the oasis and the reasons for its deterioration.
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Liu, Yi, Mengyang Shen, Jianping Zhao, Heng Dai, Dongwei Gui, Xinlong Feng, Jiali Ju, Shilei Sang, Xiaoying Zhang, and Bill Hu. "A New Optimization Method for the Layout of Pumping Wells in Oases: Application in the Qira Oasis, Northwest China." Water 11, no. 5 (May 9, 2019): 970. http://dx.doi.org/10.3390/w11050970.
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Oases are vital habitat areas for both humans and wild plants and animals in desert areas of arid Northwestern China. The efficient management of oasis water resources, especially groundwater resources, is very important for the environmental sustainability and economic development of the region. Pumping wells play a vital role in the oasis groundwater supply; therefore, optimizing the layout of these wells is essential for water resource management. In this study, we present a novel optimization methodology that implements a genetic algorithm and nonlinear programming model for the layout of pumping wells. The methodology was tested and evaluated in the real oasis case study of Qira Oasis located in southern Xinjiang Province, China. The optimization result shows that only 68 pumping wells are required for irrigation purposes of Qira Oasis, and this layout reduces the number of current pumping wells strongly by 59%. Thus, a large number of pumping wells can be closed to save resources. The optimizing method presented in this research is mathematically general and can be applied to other oasis areas without any obstacles. This method can provide decision-makers and managers with key information to ensure the optimal management and safety of valuable groundwater resources in oases.
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Zhang, Qifei, Congjian Sun, Yaning Chen, Wei Chen, Yanyun Xiang, Jiao Li, and Yuting Liu. "Recent Oasis Dynamics and Ecological Security in the Tarim River Basin, Central Asia." Sustainability 14, no. 6 (March 13, 2022): 3372. http://dx.doi.org/10.3390/su14063372.
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As an important agricultural and gathering area in arid inland areas of China, the ecological environments of oasis areas are more sensitive to regional climate change and human activities. This paper investigates the dynamic evolution of the oases in the Tarim River basin (TRB) and quantitatively evaluates the regional ecological security of oases via a remote sensing ecological index (RSEI) and net primary productivity (NPP) through the Carnegie–Ames–Stanford approach (CASA) from 2000 to 2020. The results indicate that the total plain oasis area in the TRB during the study period experienced an increasing trend, with the area expanding by 8.21%. Specifically, the artificial oases (cultivated and industrial land) showed a notable increase, whereas the natural oases (forests and grassland) exhibited an apparent decrease. Among the indictors of oasis change, the Normalised Difference Vegetation Index (NDVI) increased from 0.13 to 0.16, the fraction of vegetation cover (FVC) expanded by 36.79%, and NPP increased by 31.55%. RSEI changes indicated that the eco-environment of the TRB region went from poor grade to general grade; 69% of the region’s eco-environment improved, especially in western mountainous areas, and less than 5% of the regions’ eco-ecological areas were degraded, mainly occurring in the desert-oasis ecotone. Changes in land- use types of oases indicated that human activities had a more significant influence on oases expansion than natural factors. Our results have substantial implications for environment protection and sustainable economic development along the Silk Road Economic Belt.
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Pardaev, Ahrorqul Hasanovich. "The History Of Irrigated Agriculture In The Jizzakh Oasis." American Journal of Social Science and Education Innovations 03, no. 05 (May 7, 2021): 128–32. http://dx.doi.org/10.37547/tajssei/volume03issue05-23.
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This article studies irrigated agriculture in the Jizzakh oasis based on written and archaeological sources. The irrigation system of the Jizzakh oasis of the XVI-XIX centuries, the terms associated with irrigation, the agricultural oases formed during this period have been scientifically studied.
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Zhang, Qinglan, Min Yan, Li Zhang, Wei Shao, Yiyang Chen, and Yuqi Dong. "Three Decades of Oasis Transition and Its Driving Factors in Turpan–Hami Basin in Xinjiang, China: A Complex Network Approach." Remote Sensing 16, no. 3 (January 25, 2024): 465. http://dx.doi.org/10.3390/rs16030465.
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As a predominant ecosystem-providing area and distinctive landscape in arid regions, an oasis plays an important role in maintaining land stability, human production, and daily activities. Studying the dynamics of oasis and its driving factors is vital to supporting arid regions’ sustainable development. As a typical mountain–desert–oasis landscape, the Turpan–Hami (Tuha) Basin, located in Xinjiang, China, includes complex interactions among different land types. For this study, we revealed the spatio-temporal patterns and transition processes of the oasis using a complex network method between 1990 and 2020 in the Tuha Basin. In the oasis transition network, the degree value, betweenness centrality, and average path length were calculated to express the transition relationship, key oasis type, and oasis structural stability, respectively. Six factors related to climate change and human actives were selected to investigate the driving forces behind oasis transitions, including the average temperature and precipitation in the growing season, the total power of agricultural machinery (TAMP), the production of raw coal (PRC), the total output value of the plantation industry (TPI), and the population (Pop). Our results show that the oasis area of the Tuha Basin, including the natural oasis and artificial oasis, all grew from 1990 to 2020, with the natural oasis expanding more than the artificial oasis. The transitions between oasis types became more frequent as the area of oasis land types increased throughout the study period. Grassland acted as the most important oasis type in the network, with the highest betweenness centrality, but its importance declined due to the increasing complexity of the oasis transition network from 1990 to 2020. The transitions between oasis types became simpler, and the oasis structural stability decreased. Through driving force analysis, the oasis changes showed a positive correlation with the temperature (p-value < 0.05, r = 0.88), and urbanization and industrialization factors prompted transitions to built-up areas and cropland from grassland and shrubland. In summary, our results suggest that to create a harmonious symbiotic relationship between the natural environment in dryland and human activities, preventing grassland degradation and excessive reclamation of land cover is an available way. Meanwhile, the protection of shrubland and water resources is also important. This study provided reference and theory support for promoting the sustainable development of oases.
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Liu, Shaomin, Ziwei Xu, Tao Che, Xin Li, Tongren Xu, Zhiguo Ren, Yang Zhang, et al. "A dataset of energy, water vapor, and carbon exchange observations in oasis–desert areas from 2012 to 2021 in a typical endorheic basin." Earth System Science Data 15, no. 11 (November 10, 2023): 4959–81. http://dx.doi.org/10.5194/essd-15-4959-2023.
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Abstract. Oases and deserts generally act as a landscape matrix and mosaic in arid and semiarid regions. The significant difference in thermal and dynamic characteristics between an oasis and desert surface will result in oasis–desert interaction. Specifically, this refers to the interaction between an oasis and desert system via the exchange of momentum, energy, water, and carbon, which can lead to a series of microclimate effects that affect the structure of the atmospheric boundary layer, changes in carbon sources and sinks in an oasis, and the local ecological environment. Therefore, studying water, heat, and carbon exchange is significant to achieve the goals of carbon peaking and carbon neutrality in oasis–desert areas and support the ecological security and sustainable development of oases. To monitor energy, water vapor, and carbon exchange between the land surface and atmosphere, a land surface process integrated observatory network was established in the oasis–desert area in the middle and lower reaches of the Heihe River basin, the second largest endorheic basin in China. In this study, we present a suite of observational datasets from artificial and natural oasis–desert systems that consist of long-term energy, water vapor, carbon and methane fluxes as well as auxiliary data involving hydrometeorology, vegetation, and soil parameters from 2012 to 2021. Half-hourly turbulent flux data were acquired by an eddy covariance system and scintillometer. The hydrometeorological data (including radiation, soil heat flux, and soil temperature profiles; gradients of air temperature and humidity and of wind speed and direction; and air pressure, precipitation, and soil moisture profiles) were observed from automatic weather stations with a 10 min average period as well as the groundwater table data. Moreover, vegetation and soil parameters were also supplemented in the datasets. Careful data processing and quality control were implemented during data production, including data collection, processing, archiving, and sharing. The current datasets can be used to explore the water–heat–carbon process and its mechanism of influence; to calibrate and validate related remote-sensing products; to simulate energy, water vapor, and carbon exchange in oasis and desert areas; and to provide references and representatives for other similar artificial and natural oases along the “Silk Road”. The data are available from the National Tibetan Plateau Third Pole Environment: https://doi.org/10.11888/Terre.tpdc.300441 (Liu et al., 2023).
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Bertranou, A. V. "‘Oasis'* Systems Management." Water Science and Technology 19, no. 9 (September 1, 1987): 225–30. http://dx.doi.org/10.2166/wst.1987.0084.
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This paper describes ‘oases' as an integrated basis for rational water management, and integrated management as a tool for rational decision-making. In the evolution of man's relationship with water, three phases (the uses phase, the resources phase, and the environment phase) and three stages (legal, institutional, and integrative), are identified, which are examined in three areas (Argentina, Latin America, and the world) . The challenge of water resources management is to move from fragmented (closed) to complete (open) ‘oases', the ultimate goal being to restore man's relationship with nature. Integrated management of water resources is presented as a way of solving the problems that tend to dissociate man from institutions. Integrated management is a versatile tool that goes beyond the limits of disciplines that result in partial views of reality. It is also a specialized tool that promotes a harmonious relationship between natural and cultural sciences. *In this paper, the word ‘oasis' is not given its customary meaning of “a fertile spot in the desert”. Instead, the definition the author wishes to ascribe to the word ‘oasis' is as follows: “An ecologic subsystem within the natural ecosystem, the differentiating element of which is the presence of water in all its dimensions (technical, economic, administrative/ institutional, political). The ‘oasis' is a potentially open subsystem which permits the integration of man and nature.”
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Kurbatova, L. E., M. P. Andreev, and A. V. Dolgikh. "Bryophytes of the oasis Molodyoznyi (Enderby Land, Antarctica)." Novosti sistematiki nizshikh rastenii 48 (2014): 365–73. http://dx.doi.org/10.31111/nsnr/2014.48.365.
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For the first time the bryoflora of oasis Molodyoznyi (Enderby Land, Antarctica) was investigated in details. Detailed field studies in 2010–2013, generalization of literature data and study of collections from Bryological Herbarium of Komarov Botanical Institute (LE) resulted in records of eight moss species. Four species (Bryum archangelicum Bruch et Schimp., B. argenteum Bruch et Schimp., Coscinodon lawianus (J. H. Willis) Ochyra и Schistidium antarctici (Card.) L. I. Savicz et Smirnova) are new for oasis Molodyoznyi. Coscinodon lawianus and Schistidium antarctici are new for Enderby Land. Representative specimens and data on habitats and associated species are provided. The moss vegetation of oasis Molodyoznyi is very poor and typical for continental coastal oases of Antarctica. The most common mosses are Ceratodon purpureus and Bryum pseudotriquetrum. Bryum argenteum, Coscinodon lawianus and Schistidium antarctici are rare in oasis Molodyoznyi and Hennediella heimii (Hedw.) R. H. Zander and Orthogrimmia sessitana (De Not.) Ochyra et Żarnowiec are known for oasis Molodyoznyi from the literature only.
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Gore, Damian B. "Blanketing snow and ice; constraints on radiocarbon dating deglaciation in East Antarctic oases." Antarctic Science 9, no. 3 (September 1997): 336–46. http://dx.doi.org/10.1017/s0954102097000412.
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Radiocarbon dating of marine, lacustrine or terrestrial biogenic deposits is the main technique used to determine when deglaciation of the oases of East Antarctica occurred. However, at many of the oases of East Antarctica, including the Schirmacher Oasis, Stillwell Hills, Amery Oasis, Larsemann Hills, Taylor Islands and Grearson Oasis, snow and ice presently forms extensive blankets that fills valleys and some lake basins, covers perennial lake ice and in places overwhelms local topography to form ice domes up to hundreds of square kilometres in area. Field observations from Larsemann Hills and Taylor Islands suggest that under these conditions, terrestrial and lacustrine biogenic sedimentation is neither widespread nor abundant. If similar conditions prevailed in and around the oases immediately following retreat of the ice sheet, then a lengthy hiatus might exist between deglaciation and the onset of widespread or abundant biogenic sedimentation. As a result, radiocarbon dating might be a clumsy tool with which to reconstruct deglaciation history, and independent dating methods that record emergence of the hilltops from the continental ice must be employed as well.
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Song, Keyu, Weiming Cheng, Baixue Wang, Hua Xu, Ruibo Wang, and Yutong Zhang. "Study on the Expansion Potential of Artificial Oases in Xinjiang by Coupling Geomorphic Features and Hierarchical Clustering." Remote Sensing 16, no. 10 (May 10, 2024): 1701. http://dx.doi.org/10.3390/rs16101701.
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The study of the expansion potential of artificial oases based on remote sensing data is of great significance for the rational allocation of water resources and urban planning in arid areas. Based on the spatio-temporal relationship between morphogenetic landform types and the development of artificial oases in Xinjiang, this study explored the development pattern of artificial oases in the past 30 years by using trend analysis and centroid migration analysis, constructing a series of landform–artificial oasis change indices, and investigating the suitability of different landforms for the development of artificial oases based on geomorphological location by adopting a hierarchical clustering method. The following conclusions are drawn: (1) From 1990 to 2020, the area of artificial oases in the whole territory continued to increase, with significant expansion to the south from 2005 to 2010. (2) Six categories of landform types for artificial oasis development were created based on the clustering results. Of these, 7.39% and 6.15% of the area’s geomorphological types belonged to the first and second suitability classes, respectively. (3) The optimal scale for analyzing the suitability of landforms for the development of artificial oases over the past 30 years in the whole area was 8 km, which could explain more than 96% of the changes in the growth of artificial oases. The distribution of landforms of first- and second-class suitability within the 8 km buffer zone of an artificial oasis in the year 2020 was 10.55% and 9.90%, respectively, and landforms of first-class suitability were mainly concentrated in the near plain side of the urban agglomerations located on the northern and southern slopes of the Tianshan Mountains, and the urban agglomerations at the southern edge of Altai Mountains. This study quantified the potential of different geomorphological types for the development of artificial oases and provided a basis for site selection in future artificial oasis planning and urban construction.
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Matallah, Mohamed Elhadi, Djamel Alkama, Waqas Ahmed Mahar, and Shady Attia. "The assessment of outdoor thermal comfort inside oasis settlements in North Africa - Algeria." Journal of Physics: Conference Series 2042, no. 1 (November 1, 2021): 012061. http://dx.doi.org/10.1088/1742-6596/2042/1/012061.
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Abstract Oasis settlements are the most common form in the Saharan regions of North Africa, identified by a strong harmony between urban forms and palm groves, which present the economic capital for these regions. On the other hand, these oases are significantly growing and impacting the people’s livelihood and thermal well-being, especially during summer season. This study aims at first to identify the close correlation between cultivated area (palm grove) and the built-up area throughout the Tolga Oasis Complex in Algeria, which is recognised by its palm groves and well-known as one of the largest oasis settlements of the Saharan regions in North Africa. Furthermore, the current work assesses the impact of palm groves by investigating the ‘oasis effect’ on the thermal heat stress levels during July and August daytime hours within 9 conducted stations. Suprisingly, the so-called oasis effect generated by palm groves was insignificant during the extreme hot days. On the other hand, the palm groves were extremly hot affected by a warming effect during daytime hours.
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Addoun, Tayeb. "Discovering agricultural fires and role of the various actors in the South-East of Algerian Sahara: the case of Berriane oasis." Revista Agraria Academica 5, no. 6 (November 1, 2022): 1–12. http://dx.doi.org/10.32406/v5n6/2022/1-12/agrariacad.
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This research aims to identify the various actors and their missions to fire management in Berriane oasis; a south-east region of Algeria known for its challenging environment and dense oases. The research is conducted in three main steps respectively involving the characterization of oases fires in the Berriane region, analysis of the spatial variability of fire in relation to the human and environmental factors, and finally, role of the different actors by the MACTOR method. The analysis of structured games between actors allowed assessing their influences and dependencies. Results confirm the role of actors of agricultural fires management the protection of the oasis ecosystem.
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Mohammed, Maged, Ahmed El Mahmoudi, and Yousef Almolhem. "Applications of Electromagnetic Induction and Electrical Resistivity Tomography for Digital Monitoring and Assessment of the Soil: A Case Study of Al-Ahsa Oasis, Saudi Arabia." Applied Sciences 12, no. 4 (February 16, 2022): 2067. http://dx.doi.org/10.3390/app12042067.
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Al-Ahsa Oasis is one of the main and oldest agricultural centers in Saudi Arabia and one of the largest natural oases in the world. It is the largest irrigated agricultural oasis worldwide. The cultivated area is about 12,000 hectares in the region of Al-Ahsa. Groundwater was considered the main water source, if not the only source, for the different purposes of Al-Ahsa Oasis. However, due to groundwater depletion from these aquifers, treated wastewater is currently used to meet the shortage of irrigation water at Al-Ahsa Oasis. Today, several problems affect the agricultural productivity at Al-Ahsa Oasis, and modern geophysical techniques could contribute effectively to solving these problems; such problems are increasing soil salinity and the existence of a hardpan layer in some parts of the Al-Ahsa oasis. The soil texture is considered a critical factor to be taken into consideration. Therefore, the objectives of this study were to evaluate the effectiveness of modern geophysical techniques to study the agricultural aspects of Al-Ahsa oasis. Ten profiles of 2-D electrical tomography using SuperSting R8/IP 8 channel multielectrode resistivity and IP imaging system with 112 electrodes at one-meter spacing were implemented. Moreover, twenty electrical conductivity profiles were measured of 2240 points using EM38-MK2 at vertical mode with transmitter–receiver coils of 0.5 and one meter spacing. The results indicated that the salinity variation along the measured profiles was changed vertically and laterally due to the changes in the soil type, texture, moisture content, sabkha, and the whole oasis. Analysis and interpretation of the interpreted resistively tomograms of the ten 2-D profiles indicate remarkably the different geoelectric units of different hydrogeological conditions and soil texture across the oasis. These results will be of good utility for farmers, development sectors, and research institutions, especially in agriculture development studies, at Al-Ahsa Oasis, to ensure the sustainability of agriculture in this important historical Oasis.
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Craig, Anthony, Sophie Valcke, and Laure Coquart. "Development and performance of a new version of the OASIS coupler, OASIS3-MCT_3.0." Geoscientific Model Development 10, no. 9 (September 8, 2017): 3297–308. http://dx.doi.org/10.5194/gmd-10-3297-2017.
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Abstract. OASIS is coupling software developed primarily for use in the climate community. It provides the ability to couple different models with low implementation and performance overhead. OASIS3-MCT is the latest version of OASIS. It includes several improvements compared to OASIS3, including elimination of a separate hub coupler process, parallelization of the coupling communication and run-time grid interpolation, and the ability to easily reuse mapping weight files. OASIS3-MCT_3.0 is the latest release and includes the ability to couple between components running sequentially on the same set of tasks as well as to couple within a single component between different grids or decompositions such as physics, dynamics, and I/O. OASIS3-MCT has been tested with different configurations on up to 32 000 processes, with components running on high-resolution grids with up to 1.5 million grid cells, and with over 10 000 2-D coupling fields. Several new features will be available in OASIS3-MCT_4.0, and some of those are also described.
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Xie, Yaowen, Qiang Bie, Hui Lu, and Lei He. "Spatio-Temporal Changes of Oases in the Hexi Corridor over the Past 30 Years." Sustainability 10, no. 12 (November 29, 2018): 4489. http://dx.doi.org/10.3390/su10124489.
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In recent decades, the oases in the Hexi Corridor have gone through a tremendous transformation, which has caused a series of social and environmental problems. We aim to explore quantitatively the characteristics of the oasis expansion and their dynamic mechanism(s) in the Hexi Corridor, and their implications and impact on current and future policies. The spatial distribution pattern and dynamic changes experienced by the oases are examined using Landsat imagery. Their spatio-temporal changes are analyzed using the grid-transformed model and the dynamic-degree model. The model drivers are analyzed based on data from statistics yearbooks and field surveys. The total area of oases in the Hexi Corridor has expanded tremendously during the last 30 years from 10,709 km2 to 14,950 km2, almost 40% of the original value. Oasis evolution patterns of ‘unchanged’, ‘expanding’, ‘shrinking’, and ‘oscillating’ are observed at different periods in the three basins. In terms of area, almost half of the oases experienced some change, where most of the changes took place in the ecotone between oases and deserts, and the interior of oases due to the reclamation of abandoned land. Oasis expansion is mainly determined by the human instincts for survival and well-being, which are generally governed by population growth, agricultural policies and economic development. These changes reflect the need to find a balance in the relationship between ecological protection and increasing the well-being of local residents, because unreasonable or excessive development and utilization will cause damage to the local ecological environment.
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Salih, Abdelrahim. "Spectral Mixture Analysis (SMA) Model for Extracting Urban Fractions from Landsat and Sentinel-2A Images in the Al-Ahsa Oasis, Eastern Region of Saudi Arabia." Land 12, no. 10 (September 27, 2023): 1842. http://dx.doi.org/10.3390/land12101842.
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The rapid expansion of urban areas is a major driver of deforestation and other associated damage to the local ecosystem and environment in arid and semi-arid oases, especially in the eastern region of Saudi Arabia. It is therefore necessary to accurately map and monitor urban areas to maintain the ecosystem services in these oases. In this study, built-up areas were mapped using a spectral mixture analysis (SMA) model in the Al-Ahsa Oasis in the eastern region of Saudi Arabia by analyzing Landsat images, including Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), Operational Land Imager (OLI), and Sentinel-2A images, acquired between 1990 and 2020. Principle component analysis (PCA) was used to build and select endmembers, and then SMA was applied to each image to extract urban/built-up fractions. In addition, this study also discusses the possible driving forces of the urban dynamics. SMA classification performance was assessed using fraction error maps and a confusion matrix. The results show that the Al-Ahsa Oasis’ urban area had been rapidly expanding during 2010–2020 with an expansion rate of nearly 9%. The results also indicated that the SMA model provides high precisions (overall accuracy = ~95% to 100%) for an oasis urban mapping in an arid and semi-arid region that is disturbed by the mixed-pixel problem, such as the Al-Ahsa Oasis in eastern Saudi Arabia.
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Wan, Osanna Yee Ki, Annika Taithongchai, Susana I. Veiga, Abdul H. Sultan, and Ranee Thakar. "A one-stop perineal clinic: our eleven-year experience." International Urogynecology Journal 31, no. 11 (July 2, 2020): 2317–26. http://dx.doi.org/10.1007/s00192-020-04405-2.
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Abstract Introduction and hypothesis The perineal clinic is a dedicated setting offering assessment for various childbirth-related presentations including obstetric anal sphincter injuries (OASIs), perineal wound complications, pelvic floor dysfunction and other conditions such as female genital mutilation(FGM). We describe the clinical presentation and outcomes of women from a tertiary perineal clinic based on data collected over an 11-year period. Methods This is a retrospective observational study. A one-stop outpatient service was offered to all women who sustained OASIs (postnatally and antenatally in a subsequent pregnancy), perineal complications (within 16 weeks postpartum), FGM and/or peripartum symptoms of urinary/anal incontinence or prolapse. Assessment included history with validated questionnaires, examination and anal manometry and endoanal ultrasound when appropriate. Outcomes were compared among different grades of OASIs. Management of each type of presentation was reported with outcomes. Results There were 3254 first attendance episodes between 2006 and 2016. The majority (58.1%) were for OASIs, followed by perineal wound complications. Compared to the lower grades, the higher grades of OASI were associated with poorer outcomes in terms of symptoms, investigations and complications. Women with OASIs had unrelated symptoms such as urinary incontinence, perineal pain and wound infections that needed further intervention. A high proportion(42%) of wound complications required further specialist management. Conclusion We describe a dedicated, one-stop perineal clinic model for antenatal and postnatal women for management of perineal and pelvic floor disorders. This comprehensive and novel data will enable clinicians to better counsel women regarding of outcomes after OASI and focus training to minimize risks of morbidities.
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Yang, Yan, Zhengli Zhou, Liuji Shen, Yachong Zhao, Yuansheng Tang, and Jiahe Tian. "Effects of Stand Structure of Artificial Shelter Forest on Understory Herb Diversity in Desert-Oasis Ecotone." Diversity 15, no. 10 (October 13, 2023): 1083. http://dx.doi.org/10.3390/d15101083.
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The relationship between the spatial structure of shelter forests and the diversity of understory herbaceous plants in desert–oasis ecotones is important for maintaining biodiversity indices and protecting the oasis ecosystem. In this paper, we explore the coupling relationship between tree layer structure (competition index, angle scale, neighborhood comparison, DBH, etc.) and understory herb diversity in the transition zone of shelter forest plots near oases and near deserts; in addition, we also aim to elucidate the dominant stand structure factors affecting herb biodiversity. The results indicated the following: A total of 13 herbaceous plant species were discovered in the transitional zone, with 11 species found near the oasis area and 4 species near the desert region. The Shannon, Simpson, and Pielou indices of understory herbaceous plants were significantly higher near the oasis area compared to the desert region. The Margalef index mean was higher in the oasis area compared to the desert region. Pearson and canonical correlation analyses revealed significant associations between specific stand structure indicators and diversity in the herbaceous layer. The results of the multiple linear regression analysis revealed that the competition index had a significant impact on the Shannon, Simpson, and Pielou diversity indices of the herbaceous layer in the understory of the shelterbelt forest near the oasis, with corresponding impact coefficients of 0.911, 0.936, and 0.831, respectively. The mingling degree was found to be the primary influencing factor for the Margalef index, with an impact coefficient of 0.825. However, in the understory of the shelterbelt forest near the desert, the neighborhood comparison ratio negatively affected the Shannon and Margalef indices, with impact coefficients of −0.634 and −0.736, respectively. Additionally, tree height negatively impacted the Simpson and Pielou indices, with impact coefficients of −0.645 and −0.677, respectively. In order to enhance the diversity of understory herbaceous species in the transitional zone and preserve the ecological system of the oasis, specific modifications to the forest structure and arrangement are essential. Pruning and thinning are necessary for shelterbelt forests located near desert regions, while shelterbelt forests near oases should use a suitable mix of tree species. These measures can help preserve or enhance the diversity of understory herbaceous plants.
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Amuti, T., and G. Luo. "Analysis of land cover change and its driving forces in a desert oasis landscape of southern Xinjiang, China." Solid Earth Discussions 6, no. 2 (July 28, 2014): 1907–47. http://dx.doi.org/10.5194/sed-6-1907-2014.
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Abstract. The combined effects of drought, warming and the changes in land cover have caused severe land degradation for several decades in the extremely arid desert oases of Southern Xinjiang, Northwest China. This study examined land cover changes during 1990–2008 to characterize and quantify the transformations in the typical oasis of Hotan. Land cover classifications of these images were performed based on the supervised classification scheme integrated with conventional vegetation and soil indexes. Change-detection techniques in remote sensing (RS) and a geographic information system (GIS) were applied to quantify temporal and spatial dynamics of land cover changes. The overall accuracies, Kappa coefficients, and average annual increase rate or decrease rate of land cover classes were calculated to assess classification results and changing rate of land cover. The analysis revealed that major trends of the land cover changes were the notable growth of the oasis and the reduction of the desert–oasis ecotone, which led to accelerated soil salinization and plant deterioration within the oasis. These changes were mainly attributed to the intensified human activities. The results indicated that the newly created agricultural land along the margins of the Hotan oasis could result in more potential areas of land degradation. If no effective measures are taken against the deterioration of the oasis environment, soil erosion caused by land cover change may proceed. The trend of desert moving further inward and the shrinking of the ecotone may lead to potential risks to the eco-environment of the Hotan oasis over the next decades.
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Zhou, Xiangyang, Zhipan Niu, and Wenjuan Lei. "Estimation of Precipitation Evolution from Desert to Oasis Using Information Entropy Theory: A Case Study in Tarim Basin of Northwestern China." Water 10, no. 9 (September 15, 2018): 1258. http://dx.doi.org/10.3390/w10091258.
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The cold-wet effect of oasis improves the extreme natural conditions of the desert areas significantly. However, the relationship between precipitation and the width of oasis is challenged by the shortage of observed data. In this study, the evolution of annual precipitation from desert to oasis was explored by the model establishment and simulation in Tarim Basin of northwestern China. The model was developed from the principle of maximum information entropy, and was calibrated by the China Meteorological Forcing Dataset with a high spatial resolution of 0.1° from 1990 to 2010. The model performs well in describing the evolution of annual precipitation from the desert to oasis when the oasis is wide enough, and the R2 is generally more than 0.90 and can be up to 0.99. However, it fails to simulate the seasonal precipitation evolution because of the non-convergence solved by nonlinear fitting and the unfixed upper boundary condition solved by the least square method. Through the simulation with the parameters obtained from the nonlinear fitting, the basic patterns, four stages of precipitation evolution with the oasis width increasing, are revealed at annual scale, and the current stages of these oases are also uncovered. Therefore, the establishment of the model and the simulated results provide a deeper insight from the perspective of informatics to understand the regional precipitation evolution of the desert–oasis system. These results are not only helpful in desertification prevention, but also helpful in fusing multisource data, especially in extreme drought desert areas.
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de la Vaissière, Étienne. "Early Medieval Central Asian Population Estimates." Journal of the Economic and Social History of the Orient 60, no. 6 (November 17, 2017): 788–817. http://dx.doi.org/10.1163/15685209-12341438.
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Abstract Census data from 8th-century Eastern Central Asian oases, combined with the measurements of the oases and data from archives discovered there, allow us to calculate estimates both of the individual oases’ populations and of their respective feeding capacities, which is to say the number of people who could be fed from the output of one hectare of agricultural land. These numbers in turn have parallels in Western Central Asia, where oasis sizes can also be calculated by examination of preserved archaeological landscapes and oasis walls. It is therefore possible to reach a rough idea of the populations dwelling in the main oases and valleys of sedentary Central Asia. As regards nomadic regions, the data are far more hypothetical, but references in certain sources to the sizes of nomad armies and rates of nomadic military levying can allow us to calculate at least the possible scales of magnitude for populations living to the north of the Tianshan.
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Houssni, Mhammad, Jalal Kassout, Mohamed El Mahroussi, Soufian Chakkour, Mohamed Kadiri, Mohammed Ater, and Alexandru-Ionut Petrisor. "Evaluation and Structuring of Agrodiversity in Oases Agroecosystems of Southern Morocco." Agriculture 13, no. 7 (July 17, 2023): 1413. http://dx.doi.org/10.3390/agriculture13071413.
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Oases play a crucial role in human societies and the conservation of biodiversity, especially in harsh environments like arid zones. They serve as sanctuaries for agrodiversity, preserving diverse agricultural resources under challenging climatic conditions. However, these agroecosystems are becoming increasingly vulnerable to climate fluctuations, droughts, and other environmental changes. Understanding these unique agroecosystems is essential for developing effective strategies to protect them. Agrodiversity serves as a key indicator of the overall health of traditional agroecosystems. To assess the richness and diversity of agrodiversity, field surveys were conducted in six representative oases in southern Morocco. Within each oasis, we interviewed 20 farmers in five ksour. Our findings confirm the widespread practice of polyculture and reveal significant diversity among the oases. A total of 55 crops were identified, consisting of 183 varieties. Specifically, the oasis of Tata employed 42 crops, Alnif had 41 crops, Guelmim had 38 crops, Aoufouss had 32 crops, Rich had 29 crops, and Zagora had 28 crops. The profiles of varieties clearly distinguish between ksour and oases, highlighting the unique identities of each oasis. The modernization of farming practices is influenced by factors such as farm size, plot fragmentation, dispersal, and irrigation methods. However, its consequences are concerning. There is a risk of losing agrodiversity and compromising the food security of local populations. The shift from household consumption crops to cash crops has negative implications for the availability of diverse and nutritious food. Moreover, modernization often leads to increased water consumption, further straining the already limited water resources in these oases.
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Bourque, Charles P.-A., and Quazi K. Hassan. "Vegetation Control in the Long-Term Self-Stabilization of the Liangzhou Oasis of the Upper Shiyang River Watershed of West-Central Gansu, Northwest China." Earth Interactions 13, no. 13 (December 1, 2009): 1–22. http://dx.doi.org/10.1175/2009ei286.1.
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Abstract This paper explores the relationship between vegetation in the Liangzhou Oasis in the Upper Shiyang River watershed (USRW) of west-central Gansu, China, and within-watershed precipitation, soil water storage, and oasis self-support. Oases along the base of the Qilian Mountains receive a significant portion of their water supply (over 90%) from surface and subsurface flow originating from the Qilian Mountains. Investigation of vegetation control on oasis water conditions in the USRW is based on an application of a process model of soil water hydrology. The model is used to simulate long-term soil water content (SWC) in the Liangzhou Oasis as a function of (i) monthly composites of Moderate Resolution Imaging Spectroradiometer (MODIS) images of land surface and mean air temperature, (ii) spatiotemporal calculations of monthly precipitation and relative humidity generated with the assistance of genetic algorithms (GAs), and (iii) a 80-m-resolution digital elevation model (DEM) of the area. Modeled removal of vegetation is shown to affect within-watershed precipitation and soil water storage by reducing the exchange of water vapor from the land surface to the air, increasing the air’s lifting condensation level by promoting drier air conditions, and causing the high-intensity precipitation band in the Qilian Mountains to weaken and to be displaced upward, leading to an overall reduction of water to the Liangzhou Oasis.
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Liu, Yuanyuan, Caihong Ma, Zhonghua Yang, and Xin Fan. "Ecological Security of Desert–Oasis Areas in the Yellow River Basin, China." Land 12, no. 11 (November 18, 2023): 2080. http://dx.doi.org/10.3390/land12112080.
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The desert–oasis interaction zone plays a crucial role in safeguarding oasis ecological security and maintaining stability within oases. This paper proposed a framework of EN-DSS, based on long-term remote sensing data and fundamental data, adopted morphological spatial pattern analysis (MSPA) and Linkage Mapper among other methods, and it took Lingwu City in the Ningxia Hui Autonomous Region, which is located in the desert–oasis interaction zone in the upper reaches of the Yellow River, as a case study. The results indicate the following: since 1995, this desert–oasis system has exhibited the characteristics whereby the oasis is expanding eastward and the desert is significantly receding. The vegetation coverage has improved overall, forming an ecological security pattern characterized predominantly by shrub forests, which is referred to as the “one core, two corridors, three zones, and multiple clusters” pattern. This pattern has significantly reduced the risk of wind and sand erosion in the agricultural irrigation areas along the Yellow River. However, the construction of this ecological security pattern still faces challenges, including high construction and maintenance costs and the need to enhance the network’s quality. In the future, it will be necessary to strengthen the integrated ecological network construction of ecological areas, agricultural areas, and urban areas to enhance the stability of this regional ecological network system.
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Sraïri, Mohamed Taher, Salah Mansour, Mohamed Benidir, Mohammed Bengoumi, and Véronique Alary. "How Does Livestock Contribute to the Efficiency of the Oases’ Farming Systems?" Jordan Journal of Agricultural Sciences 15, no. 1 (March 1, 2019): 1–14. http://dx.doi.org/10.35516/jjas.v15i1.35.
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Multiple constraints, such as increased demographic pressure and growing competition for limited water resources, are significantly affecting farming systems in the oases. The combination of these constraining factors impacts the efficiency of inputs’ uses and hampers the incomes from agricultural activities. Livestock has always been a component of the oasis farming systems, covering a wide range of functions: transportation, soil preservation, income generation through meat and milk, draft, and saving. Faced with the recent changes, this study aimed to characterize the roles and contribution of livestock on the overall performances of the oasis farming systems. To do so, twelve farms illustrating four types of livestock systems were selected. Within each farm, we calculated common agricultural efficiency indicators to assess the use efficiency of the most critical production factors in the oasis: land, labor, water, and capital. The results demonstrated that efficient oasis farming systems rely on the crops/livestock association. Thereby, while providing self-consumed food products, livestock intensified farming systems (D’man prolific sheep with off-farm feed resources and dairy cattle) allow an increase in crops’ yields and their incomes. This is particularly obvious for date palms’ incomes, which benefit from the surplus irrigation of the underlying lucerne. In parallel, in specific contexts of the oases where the intensification of agriculture is quite impossible (for instance within areas with scarce groundwater or saline water, or in farms with limited capital) livestock remains the main source of income, adding value to the vast pastoral areas and the by-products of crops (wastes of dates, wheat bran, and straw, etc.).
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Andreev, Mikhail, Dale Andersen, Lyubov Kurbatova, Svetlana Smirnova, and Olga Chaplygina. "Lichens, bryophytes and terrestrial algae of the Lake Untersee Oasis (Wohlthat Massiv, Dronning Maud Land, Antarctica)." Czech Polar Reports 10, no. 2 (July 1, 2020): 203–25. http://dx.doi.org/10.5817/cpr2020-2-16.
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Lake Untersee is the largest ice-covered freshwater lake in the interior of East Antarctica. The mountain oasis is situated around it in the Gruber Mts. of the Wohlthat Massif. For approximately 7,000 years the area has been free of ice and the local climate relatively stable. It is very severe, cold, and windy and dominated by intense evaporation and sublimation but with little melt. Relative humidity averages only 37%. Vegetation is sparse in the oasis and previously only poorly investigated. Two lichen species and no bryophytes were known from the area. In November-December 2018, a survey of terrestrial flora and vegetation was made. The list of lichens was completed for the area, bryophytes were found for the first time, and some terrestrial algae were collected. In total, 23 lichen species, 1 lichenicolous fungus, 1 moss, and 18 terrestrial algae were discovered for the locality. The abundance of each species within their habitats was also evaluated. The lichen flora of the Untersee Oasis is typical for continental oases and similar to other previously investigated internal territories of Dronning Maud Land, except for the very rich lichen flora of the Schirmacher Oasis.
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Zhang, Ji, Pei Zhang, Xinchen Gu, Mingjiang Deng, Xiaoying Lai, Aihua Long, and Xiaoya Deng. "Analysis of Spatio-Temporal Pattern Changes and Driving Forces of Xinjiang Plain Oases Based on Geodetector." Land 12, no. 8 (July 28, 2023): 1508. http://dx.doi.org/10.3390/land12081508.
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Water and soil resources are the key elements required to maintain the stability and sustainable development of oases in inland drylands. This study takes oases in Xinjiang as an example, and reveals the spatial and temporal distribution characteristics of oases across Xinjiang, as well as the dynamic migration and transformation process of oases and the mutual influence of human activities on oasis resources, through a combination of land movement and attitude indicators, use of a gravity model, and Geodetector. The results show that: (1) the area containing the oases in the study has expanded, increasing by 24.0% between 1990 and 2020; (2) both artificial oases (AO) and natural oases (NO) were tilted in a northeast–southwest direction, with the center point of AOs moving slightly to the northeast, and the centripetal force and dispersion degree did not change significantly; the center point of NO moved significantly to the northeast, and the dispersion degree weakened, showing spatial convergence; (3) cultivated land and grassland were the main land types of oasis evolution, and their contribution to evolution was over 70%; and (4) the Geodetector results show that the three main factors driving the evolution of oases were vegetation cover, population density, and GDP. The research results have practical implications for land-use management planning and ecological environmental protection in arid zones.
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Martens, Clarence, and Frederick H. Lochovsky. "OASIS." ACM SIGOIS Bulletin 12, no. 2-3 (November 1991): 29–42. http://dx.doi.org/10.1145/127769.122834.
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Madhyastha, Harsha V., Arun Venkataramani, Arvind Krishnamurthy, and Thomas Anderson. "Oasis." ACM SIGOPS Operating Systems Review 40, no. 1 (January 2006): 41–48. http://dx.doi.org/10.1145/1113361.1113371.
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Iqbal, Shamsi T., and Brian P. Bailey. "Oasis." ACM Transactions on Computer-Human Interaction 17, no. 4 (December 2010): 1–28. http://dx.doi.org/10.1145/1879831.1879833.
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Casey, Philip, and Ingrid Martinez-Rico. "Oasis." Sirena: poesia, arte y critica 2006, no. 1 (2006): 212–13. http://dx.doi.org/10.1353/sir.2006.0014.
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Sillitoe, Linda. "Oasis." Dialogue: A Journal of Mormon Thought 30, no. 2 (July 1, 1997): 170. http://dx.doi.org/10.2307/45226327.
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Telmissany, May. "oasis." SGMOIK-Bulletin, no. 27 (October 1, 2008): 4–5. http://dx.doi.org/10.12685/bul.27.2008.1302.
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Bai, Yunbao, Yuchuan Guo, Huijing Wang, Ning Wang, Xuan Wei, Mingtong Zhou, Tiantian Lu, and Zihui Zhang. "The Impact of Groundwater Burial Depth on the Vegetation of the Dariyabui Oasis in the Central Desert." Sustainability 16, no. 1 (December 31, 2023): 378. http://dx.doi.org/10.3390/su16010378.
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Vegetation and groundwater are important components of the ecological environment of oases in desert hinterlands and their relationship is crucial to ecosystem stability. In this study, Sentinel-2 data for 2016–2022 and measured groundwater burial depths were analysed for the Dariyabui Oasis in the hinterland of the Taklamakan Desert. The spatial and temporal changes in vegetation and groundwater burial depth from 2019 to 2022 were analysed based on the image–element dichotomous model of the normalised difference vegetation index, utilising the inverse distance weight interpolation method, cubic curve regression, image–element difference, slope trend analysis, and the Markov transfer matrix for determining the temporal and spatial response law between the two. Finally, the threshold value of groundwater burial depth for different vegetation cover types was clarified. The fractional vegetation cover of the Dariyabui Oasis showed a slight increase from 2016 to 2022. Vegetation in the northwest and southeast of the oasis increased, whereas vegetation decreased in the mid-north and northeast regions; 5.14% of the total area experienced increased coverage, whereas 3.35% experienced decreased coverage. The depth of groundwater in the oasis showed a pattern of gradual increase from the entrance to the end of the oasis, that is, south to north. The depth of groundwater in the oasis from 2019 to 2022 was stable, with a 4-year average depth of 4.1069 m and a maximum fluctuation of 0.4560 m. The interannual changes in the groundwater level showed an increasing trend in January–April, while groundwater levels showed a decreasing trend in May–July and August–October and remained constant in June–July and October–December. Oasis vegetation cover showed a negative correlation with groundwater depth, with a depth interval for the highest low-cover vegetation distribution of 3–6 m, and an ultimate depth threshold of 7 m. The depth interval with the highest medium-cover vegetation distribution was 3–4 m, that with the highest high-cover distribution was 2–4 m, and the ultimate depth threshold was 6 m. The depth of the oasis ranged from 3 to 6 m and the ultimate depth threshold was 7 m.
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Walker, Taniya, Ciara Bryson, Sara Rahman, and Charelle Carter-Brooks. "Risk of Obstetric Anal Sphincter Injury by Delivering Provider." Reproductive Medicine 5, no. 2 (May 8, 2024): 57–64. http://dx.doi.org/10.3390/reprodmed5020007.
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Introduction and Hypothesis: Obstetric anal sphincter injuries (OASIs) complicate 5.8% of vaginal deliveries. Our objective was to assess if the primary delivery provider, a nurse-midwife versus physician obstetrician, is associated with OASIs. Methods: We performed a secondary analysis of the Consortium of Safe Labor, a multicenter, retrospective cohort study. Included were nulliparous women with singleton, vaginal delivery at ≥37 weeks from 2002 to 2008. Women were excluded if delivery was complicated by shoulder dystocia or from sites without midwife deliveries. Student’s t-tests, chi-squared analysis, and Fisher’s exact test were used as appropriate. Multivariable logistic regression and propensity score-matching analyses were performed. Results: Of 228,668 births at 19 sites, 2735 births from 3 sites met the inclusion criteria: 1551 physician and 1184 midwife births. Of all births, 4.2% (n = 116) were complicated by OASIs. Physician patients were older, more often White, privately insured, with higher BMI, more medical co-morbidities, and labor inductions/augmentations. Midwife patients had higher fetal gestational age and infant birth weights (all p < 0.05). OASIs were more common in physician compared to midwife births (5.9% vs. 2.0%, p < 0.0001). This difference persisted in multivariable logistic regression. OASIs were 2.4 (95%CI 1.5–3.9) times more likely with physician delivery when controlling for maternal heart disease, episiotomy, increasing maternal age, decreasing maternal BMI, non-White race, and increasing birthweight. The AUC was 0.78. With propensity score matching, OASI rates remained higher amongst physician births (6.6% vs. 1.8%, p < 0.0001; aOR 3.8 (95%CI 2.0–7.1)). Conclusion: OASIs were more common in physician compared to midwife deliveries even when controlling for other associated factors.
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Yi, Fan, Qiankun Yang, Zhongjing Wang, Yonghua Li, Leilei Cheng, Bin Yao, and Qi Lu. "Changes in Land Use and Ecosystem Service Values of Dunhuang Oasis from 1990 to 2030." Remote Sensing 15, no. 3 (January 17, 2023): 564. http://dx.doi.org/10.3390/rs15030564.
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Maintaining the integrity and stability of oasis ecosystems is an important topic in the field of ecological research. Assessment of ecosystem services and their changes can provide important support for the sustainable development of oases. This study took the Dunhuang oasis in the hyper-arid area as the research object and used 1990, 2010, and 2020 Landsat series satellite images to complete the land use interpretation by random forest classification. Then we estimated the ecosystem services value (ESV) by using benefit transfer method, and predicted the trend of ecosystem service value changes under three scenarios using the Analytic Hierarchy Process method and the patch generation land use simulation model (AHP-PLUS model). The results showed that the vegetation areas of the Dunhuang Oasis first decreased and then increased during 1990–2020. The decrease was largely due to the expansion of built-up land and farmland, and the increase was mainly contributed by the implementation of ecological protection policies. The path of changes in the ESV of the Dunhuang Oasis during 1990–2020 was well consistent with that of vegetation areas, with a maximum of 9068.15×106 yuan (in 1990) and a minimum of 6271.46×106 yuan (in 2010). Spatial autocorrelation analysis showed that urbanization reduced ESV, and the implementation of ecological policies enhanced ESV. The ESV of the Dunhuang Oasis for the year 2030 under the ecological conservation scenario could reach 7631.07×106 yuan, which is 381.1×106 yuan higher that under the economic development scenario. The ecological conservation scenario is the optimal option to achieve sustainable development of the Dunhuang Oasis. We suggested that the government should continuously enhance the protection of forests and waterbodies, reasonably restrict production and domestic water consumption, and efficiently increase the proportion of ecological water consumption. In addition, this study improved the evaluation method of oasis ESV based on the proportion of Normalized Difference Vegetation Index (NDVI) of grasslands with different coverage, which is important for improving the environment in arid areas.
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Amuti, T., and G. Luo. "Analysis of land cover change and its driving forces in a desert oasis landscape of Xinjiang, northwest China." Solid Earth 5, no. 2 (November 18, 2014): 1071–85. http://dx.doi.org/10.5194/se-5-1071-2014.
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Abstract. The combined effects of drought, warming and the changes in land cover have caused severe land degradation for several decades in the extremely arid desert oases of southern Xinjiang, northwest China. Land cover classifications of Landsat images in 1990, 2000 and 2008 were performed based on the multistage supervised classification scheme using the maximum likelihood classifier integrated with conventional vegetation and soil indexes, which improved overall accuracies by 4–5% compared to the standard classification method. Based on the detection of changes in land cover during 1990–2008 using remote sensing (RS) and a geographic information system (GIS), it can be found that the oasis significantly (+35%) increased, while the area of ecotone decreased (−43%). The major trends of the land cover changes were the notable growth of the oasis and the reduction of the desert–oasis ecotone. These changes were mainly a result of the intensified human activities such as land and water exploitation as well as overgrazing. The results of this study indicate that the oasis environment will be deteriorated by increase in potential areas of land degradation if the trend of desert moving further inward and the shrinking of the ecotone continues over the next decades.
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McDonald, Mary M. A., Marcia F. Wiseman, Maxine R. Kleindienst, Jennifer R. Smith, Nicholas Taylor, Andrew J. Wreschnig, Anne R. Skinner, and Bonnie A. B. Blackwell. "Did Middle Stone Age Khargan Peoples Leave Structural Features? ‘Site J’, The Forgotten Settlement of the ‘Empty Desert’, Kharga Oasis, Egypt: 1933 and 2011." Journal of African Archaeology 14, no. 2 (January 12, 2016): 155–79. http://dx.doi.org/10.3213/2191-5784-10291.
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G. Caton-Thompson and E. W. Gardner designated new Pleistocene cultural units at Kharga Oasis in the 1930’s: both were originally termed ‘pre-Sebilian’, but were later locally named the ‘Levalloiso-Khargan’ and ‘Khargan’ industries. High on the Bulaq scarp face, a puzzling cluster of stone ‘alignments’ was discovered in 1931–32, with a reported, but discounted, association with ‘Levalloiso-Khargan’ artefacts. Gardner excavated some features in 1933. Members of the Kharga Oasis Prehistory Project relocated ‘Site J’ in January 2011, and verified the reported Khargan associations with the features. In 2008, the project found structural features associated with Khargan artefacts in the northern Gebel Yebsa survey area, confirming earlier finds in the southern oases of Kurkur and Dungul. Evidence there, and that found in Kharga and Dakhleh oases, is now designated as the Khargan Complex. The associated built stone features of the included cultural units appear to be unique in Late Pleistocene Africa, especially at Bulaq.
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Jiang, Youyan, Wentao Du, Jizu Chen, Chunya Wang, Jinniu Wang, Wenxuan Sun, Xian Chai, Lijuan Ma, and Zhilong Xu. "Climatic and Topographical Effects on the Spatiotemporal Variations of Vegetation in Hexi Corridor, Northwestern China." Diversity 14, no. 5 (May 6, 2022): 370. http://dx.doi.org/10.3390/d14050370.
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Oases, as complex geographical landscapes, are strongly influenced by both natural variation and human activities. However, they have degenerated because of unplanned land use and water resource development. The research of oasis changes has mostly discussed single components, but multiple components, especially spatial changes to oasis vegetation, need further strengthening. Land use and NDVI were extracted based on Landsat 5/8 and Mod13A3, respectively, and a transfer matrix was constructed to analyze changes of land use in the Hexi Corridor during 2000–2020. The significant changes in the area of each land use were also quantified. Combined with regional temperature and precipitation, interpolated from meteorological data, the correlations between regional temperature, precipitation, and vegetation coverage were calculated, especially in the quantized areas with significant associations. The results showed that the area of bare land or desert decreased, while the areas of agricultural and residential land increased. The normalized difference NDVI of the studied oases increased at the rate of 0.021 per decade, which was positively related to precipitation (p < 0.05), rather than temperature; of which, farmland and planted grass land were 55.65% and 33.79% in the significantly increased area. In the area of significant positive relation between NDVI and precipitation, the ratio of grassland, farmland, and forest was 79.21%, 12.82%, and 4.06%, respectively. Additionally, changes in oasis vegetation were determined primarily by agricultural activities, which reflected a combination of natural and anthropic influences.
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Smirnova, S. V., O. Y. Chaplygina, and A. F. Luknitskaya. "Algal communities of the waterbodies of Schirmacher Oasis, East Antarctica." Arctic and Antarctic Research 66, no. 2 (July 10, 2020): 198–216. http://dx.doi.org/10.30758/0555-2648-2020-66-2-198-216.
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In continental waterbodies of Antarctic oases specific algal communities are forming. The structure and dominating complex of species of this communities due to different distance from the seashore and latitude, the composition of the constituent rocks, altitude and the presence in the past of periods of contact with sea water is unique for different oases. It may vary in different waterbodies within one oasis besides.Aim of the research is to describe different types of algal communities from the continental waterbodies of Schirmacher Oasis and it’s confinement to the different types of waterbodies.Samples were collected from 173 waterbodies: 151 with stagnant water and 22 streams.During the study 64 species of Cyanoprokaryotes were found, and this group usually dominated in communities. Also 14 most frequent species of Chlorophyta, 12 most frequent species of Bacillariophyta, 6 species of desmid algae, 2 species of Xanthophyceae, 1 species of Eustigmatophyceae were noted in benthos. Usually resting stages and in one case — life cells of Golden algae (Chrysophyceae, Synurophyceae) were found in mats on the bottom of big lakes. Plankton algae in most of the waterbodies had very low abundance and diversity and were strongly influensed by trophic level. Benthic algal communities were much more diverse and abundant. Eight sustainable types of benthic algal communities were revealed in continental waterbodyes of Schirmacher Oasis. Form, colour, and species composition of bentic films and mats strongly depended on temperature, conductivity and pH of the waterbody and its depth.
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Gabsi, Fatma, Mhammed Ehsine, and Lamia Medini-Bouaziz. "Study of the diversity of Terrestrial Isopods in the Oasis Agrosystems of Tunisia." JOURNAL OF OASIS AGRICULTURE AND SUSTAINABLE DEVELOPMENT 4, Special (June 16, 2022): 16–21. http://dx.doi.org/10.56027/joasd.spiss032022.
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In this study, several sampling campaigns of terrestrial isopods were carried out in different oases of southern Tunisia as well as in other sites outside the oases. The results made it possible to identify: in the oases, a dozen species belonging to three families Porcellionidae, Armadillidiidae and Armadillidae and in the other sites outside the oasis, only 5 species belonging to the 2 families Porcellionidae and Agnaridae. This difference in species richness could be explained by the different climatic conditions between the two sites studied. Indeed, the majority of the species collected in the oases are characteristic of the wetlands, testifying to the important role of the oases in maintaining this specific diversity of terrestrial isopods.
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Zhang, Ji, Pei Zhang, Xiaoya Deng, Cai Ren, Mingjiang Deng, Shuhong Wang, Xiaoying Lai, and Aihua Long. "Study on the Spatial and Temporal Trends of Ecological Environment Quality and Influencing Factors in Xinjiang Oasis." Remote Sensing 16, no. 11 (May 31, 2024): 1980. http://dx.doi.org/10.3390/rs16111980.
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Human activities and climate change have profound impacts on the ecological environment of oases in Xinjiang, and it is of great significance to explore the spatial and temporal evolution patterns of ecological environment quality in this region for the sustainable development of Xinjiang. The remote sensing ecological index (RSEI) was extracted from the Google Earth Engine (GEE) platform from 2000 to 2020, and the coefficient of variation and Hurst index were used to reveal the spatial and temporal characteristics and stability of the ecological environment quality of the artificial oasis and natural oasis in Xinjiang. The key factors affecting the ecological environment quality are explored through correlation analysis and geoprobes. The results show that the distribution of the ecological environment in Xinjiang oases is high in the north and low in the south, and the overall quality shows a fluctuating downward trend from 0.210 to 0.189. Artificial oases have higher RSEI values, stability, and sustainability than natural oases. The RSEI in the study area was mainly influenced by humidity, followed by greenness and heat, and dryness had the least influence on the RSEI model. Based on the geodetector, the top three highest contributors were found to be precipitation (PRE) (0.83) > relative humidity (RHU) (0.82) > evapotranspiration (ET) (0.57). Climate is the main factor affecting the ecological quality of oases, and the RSEI can be improved by increasing the proportion of artificial oases. The study aims to provide a scientific basis for the sustainable development of oases in arid zones.