As the longest desert highway in China. the 447-kin-long Taklimakan Desert Highway which goes across the Taklimakan Desert was fully opened to traffic in 1996~[1]. The sand-controlling system along the Desert Highway ...As the longest desert highway in China. the 447-kin-long Taklimakan Desert Highway which goes across the Taklimakan Desert was fully opened to traffic in 1996~[1]. The sand-controlling system along the Desert Highway enables the Highway itself to operate properly and creates enormous socio-economic benefits. However, due to delivery time pressure, the sand-controlling system was built in a haste. Lack of studies on sand-controlling system brought deficiencies on design and construction of the sand-controlling system. And with the lapse of time, troubles such as sand deposition on the roadbeds and erosion on roadsides came to surface and caused more serious problems for the traffic routes[1.2]. This paper discusses two forms of the sand-controlling system-the upright fence and the send-covered sand barrier, then analyzes the general benefits of the sandcontrolling system along the Desert Highway.展开更多
Re puted as a wonderful achievement of the world's highway construction h istory, the Taklimakan Desert highway is now facing serious sand drift encroachment problems due to its 447-km-long passage of sand sea con...Re puted as a wonderful achievement of the world's highway construction h istory, the Taklimakan Desert highway is now facing serious sand drift encroachment problems due to its 447-km-long passage of sand sea consist ing of crescent dunes, barchan chains, compound transverse dune ridges and co mplex megadunes. To solve some technical problems in the protection of the highway from sand drift encroachment, desert experts have been conductin g the theoretical and applied studies on sand movement laws; causes, severities and time-space differentiation of sand drift damages; and control ways in cluding mechanical, chemical and biological measures. In this paper the authors give an overall summary on the research contents and recent progress i n the control of sand drift damages in China and hold that the theoretica l research results and practices in the prevention of sand drift encr oachment on the cross-desert highway represent a breakthrough and has an epoch-making significance. Since the construction of protective forest along the cross-desert highway requires large amount of ground water, what will be its environmental consequence and whether it can effectiv ely halt sand drift encroachment on the highway forever are the questions to be studied urgently.展开更多
Although scientists have performed many studies in the Taklimakan Desert, few of them have reported the blown sand motion along the southern edge of the Taklimakan Desert Highway, which differs significantly from the ...Although scientists have performed many studies in the Taklimakan Desert, few of them have reported the blown sand motion along the southern edge of the Taklimakan Desert Highway, which differs significantly from the northern region in terms of aeolian sand geomorphology and formation environment. Based on the field ob- servation data of airflow and aeolian sand transport, continuous monitoring data of erosional and depositional processes between 14 April 2009 and 9 April 2011 and data of surface sand grains from the classical section along the southern edge of the Taklimakan Desert Highway, this paper reported the blown sand motion within the sand-control system of the highway. The main results are as follows： 1） The existing sand-control system is highly effective in preventing and controlling desertification. Wind velocities within the sand-control system were ap- proximately 33%-100% of those for the same height above the mobile sand surface. Aeolian sand fluxes were approximately 0-31.21% of those of the mobile sand surface. Sand grains inside the system, with a mean diameter of 2.89 q）, were finer than those （2.15 q）） outside the system. In addition, wind velocities basically followed a loga- rithmic law, but the airflow along the classical section was mainly determined by topography and vegetation. 2） There were obvious erosional and depositional phenomena above the surface within the sand-control system, and these phenomena have very consistent patterns for all observation points in the two observed years. The total thicknesses of erosion and deposition ranged from 0.30 to 14.60 cm, with a mean value of 3.67 cm. In contrast, the deposition thicknesses were 1.90-22.10 cm, with a mean value of 7.59 cm, and the erosion thicknesses were 3.51-15.10 cm, with a mean value of 8.75 cm. The results will aid our understanding of blown sand within the sand-control system and provide a strong foundation for optimizing the sand-control system.展开更多
Water consumption can be reduced by using a greenhouse for agriculture in desert areas. We analyzed the effect of control of ventilation, sprinkler water, and solar radiation?shielding on changes of temperature and hu...Water consumption can be reduced by using a greenhouse for agriculture in desert areas. We analyzed the effect of control of ventilation, sprinkler water, and solar radiation?shielding on changes of temperature and humidity in a greenhouse under various desert area conditions. We calculated the changes in temperature and humidity in a greenhouse for a whole day in four seasons, and the calculation results of water consumption with and without a greenhouse were compared. When ventilation, shielding, and sprinkler water were controlled under suitable conditions to grow orchids in a desert area, water consumption in July was only 7% of that without a greenhouse.展开更多
The research objective of this review is to discuss the rationale that led to the development of Controlled Environment Agriculture (CEA) and investigate this agricultural approach as a potential solution to mitigate ...The research objective of this review is to discuss the rationale that led to the development of Controlled Environment Agriculture (CEA) and investigate this agricultural approach as a potential solution to mitigate the increased pressures on food security. It describes the need for urban cultivation systems using controlled environments and how they can be harnessed to address pressures facing food security. The factors that have contributed to the growth of CEAs, education, environmental justice, and the advantages and disadvantages of growing crops in CEAs in urban areas will be discussed. The article reviews global urban cultivation systems using controlled environments, by identifying the technologies needed to establish them. The practice of CEA is being increasingly adopted worldwide and we describe urban agriculture and compare it with traditional growing systems. Indoor farming systems that integrate into existing urban infrastructure such as vertical farming and plant factories using CEAs are discussed. Indoor farming gives urban areas enhanced access to food sources, but the cost is high, however decreasing due to recent technological advances. The current review extends the literature by incorporating recent research on the topic of agriculture in urban areas and food security. This review seeks to provide additional information regarding the viability of CEA in urban areas.展开更多
基金program introducting distinguished personnel from abroad/wind-blown sand physics project Chinese Academy of Sciences
文摘As the longest desert highway in China. the 447-kin-long Taklimakan Desert Highway which goes across the Taklimakan Desert was fully opened to traffic in 1996~[1]. The sand-controlling system along the Desert Highway enables the Highway itself to operate properly and creates enormous socio-economic benefits. However, due to delivery time pressure, the sand-controlling system was built in a haste. Lack of studies on sand-controlling system brought deficiencies on design and construction of the sand-controlling system. And with the lapse of time, troubles such as sand deposition on the roadbeds and erosion on roadsides came to surface and caused more serious problems for the traffic routes[1.2]. This paper discusses two forms of the sand-controlling system-the upright fence and the send-covered sand barrier, then analyzes the general benefits of the sandcontrolling system along the Desert Highway.
基金The National Key Project for Basic Research, No.G2000048705 Knowledge Innovation Project of the Cold and Arid Regions Environmental and Engineering Research Institute, CAS, No.CACX210093
文摘Re puted as a wonderful achievement of the world's highway construction h istory, the Taklimakan Desert highway is now facing serious sand drift encroachment problems due to its 447-km-long passage of sand sea consist ing of crescent dunes, barchan chains, compound transverse dune ridges and co mplex megadunes. To solve some technical problems in the protection of the highway from sand drift encroachment, desert experts have been conductin g the theoretical and applied studies on sand movement laws; causes, severities and time-space differentiation of sand drift damages; and control ways in cluding mechanical, chemical and biological measures. In this paper the authors give an overall summary on the research contents and recent progress i n the control of sand drift damages in China and hold that the theoretica l research results and practices in the prevention of sand drift encr oachment on the cross-desert highway represent a breakthrough and has an epoch-making significance. Since the construction of protective forest along the cross-desert highway requires large amount of ground water, what will be its environmental consequence and whether it can effectiv ely halt sand drift encroachment on the highway forever are the questions to be studied urgently.
基金supported by the National Natural Science Foundation of China (41271020, 41330746)CERS-China Equipment and Education Resources System (CERS-1-109)
文摘Although scientists have performed many studies in the Taklimakan Desert, few of them have reported the blown sand motion along the southern edge of the Taklimakan Desert Highway, which differs significantly from the northern region in terms of aeolian sand geomorphology and formation environment. Based on the field ob- servation data of airflow and aeolian sand transport, continuous monitoring data of erosional and depositional processes between 14 April 2009 and 9 April 2011 and data of surface sand grains from the classical section along the southern edge of the Taklimakan Desert Highway, this paper reported the blown sand motion within the sand-control system of the highway. The main results are as follows： 1） The existing sand-control system is highly effective in preventing and controlling desertification. Wind velocities within the sand-control system were ap- proximately 33%-100% of those for the same height above the mobile sand surface. Aeolian sand fluxes were approximately 0-31.21% of those of the mobile sand surface. Sand grains inside the system, with a mean diameter of 2.89 q）, were finer than those （2.15 q）） outside the system. In addition, wind velocities basically followed a loga- rithmic law, but the airflow along the classical section was mainly determined by topography and vegetation. 2） There were obvious erosional and depositional phenomena above the surface within the sand-control system, and these phenomena have very consistent patterns for all observation points in the two observed years. The total thicknesses of erosion and deposition ranged from 0.30 to 14.60 cm, with a mean value of 3.67 cm. In contrast, the deposition thicknesses were 1.90-22.10 cm, with a mean value of 7.59 cm, and the erosion thicknesses were 3.51-15.10 cm, with a mean value of 8.75 cm. The results will aid our understanding of blown sand within the sand-control system and provide a strong foundation for optimizing the sand-control system.
文摘Water consumption can be reduced by using a greenhouse for agriculture in desert areas. We analyzed the effect of control of ventilation, sprinkler water, and solar radiation?shielding on changes of temperature and humidity in a greenhouse under various desert area conditions. We calculated the changes in temperature and humidity in a greenhouse for a whole day in four seasons, and the calculation results of water consumption with and without a greenhouse were compared. When ventilation, shielding, and sprinkler water were controlled under suitable conditions to grow orchids in a desert area, water consumption in July was only 7% of that without a greenhouse.
文摘The research objective of this review is to discuss the rationale that led to the development of Controlled Environment Agriculture (CEA) and investigate this agricultural approach as a potential solution to mitigate the increased pressures on food security. It describes the need for urban cultivation systems using controlled environments and how they can be harnessed to address pressures facing food security. The factors that have contributed to the growth of CEAs, education, environmental justice, and the advantages and disadvantages of growing crops in CEAs in urban areas will be discussed. The article reviews global urban cultivation systems using controlled environments, by identifying the technologies needed to establish them. The practice of CEA is being increasingly adopted worldwide and we describe urban agriculture and compare it with traditional growing systems. Indoor farming systems that integrate into existing urban infrastructure such as vertical farming and plant factories using CEAs are discussed. Indoor farming gives urban areas enhanced access to food sources, but the cost is high, however decreasing due to recent technological advances. The current review extends the literature by incorporating recent research on the topic of agriculture in urban areas and food security. This review seeks to provide additional information regarding the viability of CEA in urban areas.
