Using informational digital diagrams, we analyzed the snow event that occurred on Feb 26, 2006 and the sandstorm on Apr 11, 2006 in Xi＇an. Results indicate that, under similar weather circumstances, different events ...Using informational digital diagrams, we analyzed the snow event that occurred on Feb 26, 2006 and the sandstorm on Apr 11, 2006 in Xi＇an. Results indicate that, under similar weather circumstances, different events evidently exhibit unique vertical structure features. Informational digital diagrams provide a method for transitional weather prediction, a problem for present extrapolative analysis system.展开更多
The aim of the study is to classify the Sandstorms according to year seasons as well as their spatial variation in Saudi Arabia. Factor analysis has been used for data collection. Three factors have been presented: th...The aim of the study is to classify the Sandstorms according to year seasons as well as their spatial variation in Saudi Arabia. Factor analysis has been used for data collection. Three factors have been presented: the first factor related to Spring as a prime Season for Dust Sandstorms. Factor two shows that Samar months concern as ascend season for Sandstorms, while the Autumn Season comes as a third period for Dust Sandstorms. With regard to spatial variation, Al-Ahsa station came as the most closely related station in the spring season, followed by Hafr Elbatten, Jazan and Al-Jouf stations, while Jazan and Yenbo stations were the most connected stations in the summer season, Turaif is more closely related, to Fall season. By the end of the study several results and recommendations have been addressed.展开更多
The main causes of the heavysandstorms ravaging north Chinathis spring are abnormal climateand the encroachment ofdesertification, says a CAS reportreleased in Beijing on May 15.
The influence of sandstorms on train aerodynamic performance and safe running was studied in response to the frequent occurrence of sandstorm weather in north China.An Eulerian two-phase model in the computational flu...The influence of sandstorms on train aerodynamic performance and safe running was studied in response to the frequent occurrence of sandstorm weather in north China.An Eulerian two-phase model in the computational fluid dynamic (CFD) software FLUENT,validated with published data,was used to solve the gas-solid multiphase flow of a sandstorm around a train.The train aerodynamic performance under different sandstorm levels and no sand conditions was then simulated.Results showed that in sandstorm weather,the drag,lift,side forces and overturning moment increase by variable degrees.Based on a numerical analysis of aerodynamic characteristics,an equation of train stability was also derived using the theory of moment balance from the view of dynamics.A recommended speed limit of a train under different sandstorm levels was calculated based on the stability analysis.展开更多
＂Ejin Section＂ found in a typical vegetation-covered sand dune in Ejin Oasis was investigated. In this study, 263 samples were taken from the section for grain-size analysis, 25 for chemical analysis, 11 for ^14C da...＂Ejin Section＂ found in a typical vegetation-covered sand dune in Ejin Oasis was investigated. In this study, 263 samples were taken from the section for grain-size analysis, 25 for chemical analysis, 11 for ^14C dating and 6 for scanning electron microscope （SEM）. The results of the study indicate that 3 types of the sediments in the section can be identified, YS, LS and ST. YS, homogeneous yellow-brown dune sands, is equal to those of inland deserts, LS, loess-like sandy soils, is the same as the sandy loess in the middle Yellow River and modem falling dusts, and ST, sandy sediments interbeded with the deadwood and defoliation of Tamarix spp, represents the depositional process of the section interrupted by abrupt changes in climate. The Ejin Section has recorded the repeated dust-storms or sandstorms since 2500 yr BP and the peak periods of the dust-storms or sandstorms revealed by the section are consistent with the records of ＂dust rains＂ in historical literatures, indicating that the change of climate is a key factor to increase sandstorms or dust-storms, whereas, ＂artificial＂ factor may only be an accelerating one for desertification.展开更多
Sandstorm is a frequently occurred disastrous weather in northern China. The increasing occurrence frequency recently, especially the much more frequently occurred sandstorms with high intensity in the spring of 2000 ...Sandstorm is a frequently occurred disastrous weather in northern China. The increasing occurrence frequency recently, especially the much more frequently occurred sandstorms with high intensity in the spring of 2000 have caused great loss to national economy. The combination of strong wind, exposed sandy soil on ground surface and unstable air current constitutes the necessary conditions for the sandstorms. However, the accelerated desertification process resulting from irrational human economic activities is responsible for the accelerated sandstorms. The effective measures to mitigate sandstorm lie in strengthening desertification control and eco-environmental protection.展开更多
ALASHAN AND ORDOS,Inner Mongolia-Dust,five centimeters thick, and rat holes cover the landscape of the Shilekai village,about 300 kilometers from the city of Ordos, Inner Mongolia.
Alxa League,located in the western part of Inner Mongolia,China,frequently suffers from sandstorms.Such dusty conditions result in sharp increases in respirable particulate matter(PM10)concentration in outdoor and ind...Alxa League,located in the western part of Inner Mongolia,China,frequently suffers from sandstorms.Such dusty conditions result in sharp increases in respirable particulate matter(PM10)concentration in outdoor and indoor environments,posing a significant health risk to local inhabitants.Vernacular dwellings in this area feature a specific floor plan that includes an entrance space to safeguard indoor air quality during sandstorms while being compatible with the local climate.This study utilises CONTAM,a multizone indoor air quality and ventilation analysis computer program,and field measurements to quantitatively evaluate the effectiveness of the entrance space in protecting indoor air quality against ambient PM10 pollution under both dusty and normal conditions.The simulation results reveal that the entrance space can effectively mitigate PM10 pollution in the middle room,lowering the average concentration from 47.0μg/m^(3) to 37.5μg/m^(3) during dust periods.However,PM10 pollution may increase in the entrance space,reaching an average concentration of up to 70.0μg/m^(3).Experimental outcomes align with the simulated results.Given that construction activities exacerbate desertification and frequent sandstorms,the above findings help identify the optimal design strategies for energy-efficient green vernacular dwellings in the targeted desert area,promoting environmental harmony and addressing climate change challenges.展开更多
Serious land degradation exists in the marginal areas of North China, the important ecological transition between semi-arid and sub-humid climate zones, which is a relatively narrow belt with 100-250 km in width and a...Serious land degradation exists in the marginal areas of North China, the important ecological transition between semi-arid and sub-humid climate zones, which is a relatively narrow belt with 100-250 km in width and about 2 000 km in length. The annual rainfall varies between 300-400 mm. In the past hundred years (before 2000), most of the land in the region had been used for grazing and dryland cropping. As land-use is intensifying, particularly since 1970s and 1980s, desertification has accelerated. O...展开更多
本模块知识网络词汇短语园地1. blow vt.&vi.吹;吹动;刮The winds blow across the sea, pushing little waves into bigger and bigger ones.风吹过海面,把小的波浪向前推进,变成越来越大的波浪。The wind has blown my hat off....本模块知识网络词汇短语园地1. blow vt.&vi.吹;吹动;刮The winds blow across the sea, pushing little waves into bigger and bigger ones.风吹过海面,把小的波浪向前推进,变成越来越大的波浪。The wind has blown my hat off.风把我的帽子刮走了。展开更多
Systematical analyses of spring sandstorms in 2000 affecting Beijing area are carried out. Results revealed the key dynamic mechanisms of dust storm during its mobilization, lifting, horizontal advection and depositio...Systematical analyses of spring sandstorms in 2000 affecting Beijing area are carried out. Results revealed the key dynamic mechanisms of dust storm during its mobilization, lifting, horizontal advection and deposition processes. It turns out that in the processes of sandstorms influencing Beijing area in March-April 2000, the dynamic conditions for dust mobilization are significantly correlated with phenomena, such as cold air-related climatic activities,clay soils area of North China and surface friction velocity anomaly. The characteristics of sandstorm can be described by composite mode of dust particles mobilization-lifting-long-range transport. This paper will provide scientific evidences for further studies,prediction and harness of sandstorms in China.展开更多
The English edition of China Daily on 13 September 2017 had a story(page 12) sponsored by the State Forestry Administration, which ran a campaign against desertification: The Songhe villager, Shi Shuzhu(with photo) of...The English edition of China Daily on 13 September 2017 had a story(page 12) sponsored by the State Forestry Administration, which ran a campaign against desertification: The Songhe villager, Shi Shuzhu(with photo) of Minqin County, Gansu Province, describes the collective effort to build a 9-kilometre long ‘green wall’ to keep the desert out, declaring that ‘respecting science and technology for its useful new methods is something I have learned from long periods of struggling with sandstorms’.展开更多
Mineral dust particles play an important role in the formation of secondary inorganic aerosols, which largely contribute to haze pollution in China.During this study, a haze episode(haze days) and a typical haze proce...Mineral dust particles play an important role in the formation of secondary inorganic aerosols, which largely contribute to haze pollution in China.During this study, a haze episode(haze days) and a typical haze process mixed with sandstorm(sandy haze days)were observed in Zhengzhou with a series of high-time-resolution monitoring instruments from November 22 to December 8, 2018.Concentrations of PM10 and crustal elements clearly increased in the sandy haze days.Concentrations of gaseous pollutants, metallic elements emitted from anthropogenic sources, nitrate, and ammonium during sandy haze days were slightly lower than those during the haze days but still obviously higher than those during the non-haze days.The sulfate concentrations, the sulfate fractions in PM2.5,and the sulfur oxidation ratios significantly increased in the sandy haze days.Heterogeneous reactions dominated the conversion of SO2 during the haze and sandy haze days.Enhanced SO2 conversion during the sandy haze days may be attributed to the high concentrations of transition metal ions from the sandstorm when the values of relative humidity(RH) were in 30%–70%, and high O3 at certain time points.Gas-phase NO2 oxidation reactions were the main pathways for nitrate formation.In the sandy haze days,higher nitrogen oxidation ratio(NOR) at daytime may be associated with higher RH and lower temperature than those in the haze days, which facilitate the gas-to-particle partitioning of nitrate;higher NOR values at night may be attributed to the higher O3 concentrations, which promoted the formation of N2O5.展开更多
The purpose of this present study is to investigate the frequency and variation of sandstorm in Minqin Oasis. Using daily observational data of sandstorm and other meteorologic data from 1954 to 2000, we have illumina...The purpose of this present study is to investigate the frequency and variation of sandstorm in Minqin Oasis. Using daily observational data of sandstorm and other meteorologic data from 1954 to 2000, we have illuminated the relationship between sandstorm, meteorological parameters and human activities. The results of the analysis show that the highest frequency of sandstorms occurrence and their duration mainly focus on March, April and May, especially in April. Most of sandstorms occur from midday to nightfall, but relative few appear from midnight to forenoon, which apparently correlates to the daily variations of atmospheric thermal stability within atmospheric boundary layer. Monthly mean and annual mean duration of sandstorms coincide well with the frequencies of sandstorm occurrence.展开更多
Land use change is one of the major factors that affect soil organic carbon （SOC） variation and global carbon balance. However, the effects of land use change on SOC are always variable. In this study, using a serie...Land use change is one of the major factors that affect soil organic carbon （SOC） variation and global carbon balance. However, the effects of land use change on SOC are always variable. In this study, using a series of paired-field experiments, we estimated the effects of revegetation types and environmental conditions on SOC stock and vertical distribution after replacement of cropland with poplar （Populus tomentosa） and korshinsk peashrub （Caragana korshinskt＇i） in three climate regions （Chifeng City, Fengning City and Datong City of the ＇Beijing-Tianjin Sandstorm Source Control＇ （BTSSC） program area. The results show that SOC sequestration rate ranges from 0.15 Mg/（ha-yr） to 3.76 Mg/（ha-yr） in the soil layer of 0-100 cm in early stage after cropland afforestation in the BTSSC program area. The SOC accumulation rates are the highest in Fengning for both the two vegetation types. Compared to C. korshinskii, P tomentosa has greater effects on SOC accumulation in the three climate regions, but significantly greater effect only appears in Datong. The SOC density increases by 20%-111% and 15%-59% for P. tomentosa and 9%-63% and 0-73% for C. korshinskii in the 0-20 cm and 20-100 cm soil layers, respectively. Our results indicate that cropland afforestation not only affects SOC stock in the topsoil, but also has some effects on subsoil carbon. However, the effect of cropland afforestation on SOC accumulation varied with climate regions and revegetation types. Considering the large area of revegetation and relatively high SOC accumulation rate, SOC sequestration in the BTSSC program should contribute significantly to decrease the CO2 concentration in the atmosphere.展开更多
文摘Using informational digital diagrams, we analyzed the snow event that occurred on Feb 26, 2006 and the sandstorm on Apr 11, 2006 in Xi＇an. Results indicate that, under similar weather circumstances, different events evidently exhibit unique vertical structure features. Informational digital diagrams provide a method for transitional weather prediction, a problem for present extrapolative analysis system.
文摘The aim of the study is to classify the Sandstorms according to year seasons as well as their spatial variation in Saudi Arabia. Factor analysis has been used for data collection. Three factors have been presented: the first factor related to Spring as a prime Season for Dust Sandstorms. Factor two shows that Samar months concern as ascend season for Sandstorms, while the Autumn Season comes as a third period for Dust Sandstorms. With regard to spatial variation, Al-Ahsa station came as the most closely related station in the spring season, followed by Hafr Elbatten, Jazan and Al-Jouf stations, while Jazan and Yenbo stations were the most connected stations in the summer season, Turaif is more closely related, to Fall season. By the end of the study several results and recommendations have been addressed.
文摘The main causes of the heavysandstorms ravaging north Chinathis spring are abnormal climateand the encroachment ofdesertification, says a CAS reportreleased in Beijing on May 15.
基金Project(No.2009BAG12A01-C03) supported by the National Key Technology R&D Program of China
文摘The influence of sandstorms on train aerodynamic performance and safe running was studied in response to the frequent occurrence of sandstorm weather in north China.An Eulerian two-phase model in the computational fluid dynamic (CFD) software FLUENT,validated with published data,was used to solve the gas-solid multiphase flow of a sandstorm around a train.The train aerodynamic performance under different sandstorm levels and no sand conditions was then simulated.Results showed that in sandstorm weather,the drag,lift,side forces and overturning moment increase by variable degrees.Based on a numerical analysis of aerodynamic characteristics,an equation of train stability was also derived using the theory of moment balance from the view of dynamics.A recommended speed limit of a train under different sandstorm levels was calculated based on the stability analysis.
基金National Basic Research Program of China, No.2004CB720206 Knowledge Innovation Project of CAS, No.KZCX2-SW-118
文摘＂Ejin Section＂ found in a typical vegetation-covered sand dune in Ejin Oasis was investigated. In this study, 263 samples were taken from the section for grain-size analysis, 25 for chemical analysis, 11 for ^14C dating and 6 for scanning electron microscope （SEM）. The results of the study indicate that 3 types of the sediments in the section can be identified, YS, LS and ST. YS, homogeneous yellow-brown dune sands, is equal to those of inland deserts, LS, loess-like sandy soils, is the same as the sandy loess in the middle Yellow River and modem falling dusts, and ST, sandy sediments interbeded with the deadwood and defoliation of Tamarix spp, represents the depositional process of the section interrupted by abrupt changes in climate. The Ejin Section has recorded the repeated dust-storms or sandstorms since 2500 yr BP and the peak periods of the dust-storms or sandstorms revealed by the section are consistent with the records of ＂dust rains＂ in historical literatures, indicating that the change of climate is a key factor to increase sandstorms or dust-storms, whereas, ＂artificial＂ factor may only be an accelerating one for desertification.
基金Under the auspices of National Natural Science Foundation of China (49894170)
文摘Sandstorm is a frequently occurred disastrous weather in northern China. The increasing occurrence frequency recently, especially the much more frequently occurred sandstorms with high intensity in the spring of 2000 have caused great loss to national economy. The combination of strong wind, exposed sandy soil on ground surface and unstable air current constitutes the necessary conditions for the sandstorms. However, the accelerated desertification process resulting from irrational human economic activities is responsible for the accelerated sandstorms. The effective measures to mitigate sandstorm lie in strengthening desertification control and eco-environmental protection.
文摘ALASHAN AND ORDOS,Inner Mongolia-Dust,five centimeters thick, and rat holes cover the landscape of the Shilekai village,about 300 kilometers from the city of Ordos, Inner Mongolia.
基金supported by the funding from National Natural Science Foundation of China(No.52008199)special fund of Beijing Key Laboratory of Indoor Air Quality Evaluation and Control(No.BZ0344KF20-09)China and the Fundamental Research Funds for the Central Universities(No.0902/14380035),China.
文摘Alxa League,located in the western part of Inner Mongolia,China,frequently suffers from sandstorms.Such dusty conditions result in sharp increases in respirable particulate matter(PM10)concentration in outdoor and indoor environments,posing a significant health risk to local inhabitants.Vernacular dwellings in this area feature a specific floor plan that includes an entrance space to safeguard indoor air quality during sandstorms while being compatible with the local climate.This study utilises CONTAM,a multizone indoor air quality and ventilation analysis computer program,and field measurements to quantitatively evaluate the effectiveness of the entrance space in protecting indoor air quality against ambient PM10 pollution under both dusty and normal conditions.The simulation results reveal that the entrance space can effectively mitigate PM10 pollution in the middle room,lowering the average concentration from 47.0μg/m^(3) to 37.5μg/m^(3) during dust periods.However,PM10 pollution may increase in the entrance space,reaching an average concentration of up to 70.0μg/m^(3).Experimental outcomes align with the simulated results.Given that construction activities exacerbate desertification and frequent sandstorms,the above findings help identify the optimal design strategies for energy-efficient green vernacular dwellings in the targeted desert area,promoting environmental harmony and addressing climate change challenges.
基金Funded by the National Basic Research Priorities Program (№ G2000048700)the Major Program of National Natural Science Foundation of China (№ 39990490).
文摘Serious land degradation exists in the marginal areas of North China, the important ecological transition between semi-arid and sub-humid climate zones, which is a relatively narrow belt with 100-250 km in width and about 2 000 km in length. The annual rainfall varies between 300-400 mm. In the past hundred years (before 2000), most of the land in the region had been used for grazing and dryland cropping. As land-use is intensifying, particularly since 1970s and 1980s, desertification has accelerated. O...
文摘本模块知识网络词汇短语园地1. blow vt.&vi.吹;吹动;刮The winds blow across the sea, pushing little waves into bigger and bigger ones.风吹过海面,把小的波浪向前推进,变成越来越大的波浪。The wind has blown my hat off.风把我的帽子刮走了。
基金This work was supported by Key Projects of National Fundamental Research Planning (Grant No. G1999045700).
文摘Systematical analyses of spring sandstorms in 2000 affecting Beijing area are carried out. Results revealed the key dynamic mechanisms of dust storm during its mobilization, lifting, horizontal advection and deposition processes. It turns out that in the processes of sandstorms influencing Beijing area in March-April 2000, the dynamic conditions for dust mobilization are significantly correlated with phenomena, such as cold air-related climatic activities,clay soils area of North China and surface friction velocity anomaly. The characteristics of sandstorm can be described by composite mode of dust particles mobilization-lifting-long-range transport. This paper will provide scientific evidences for further studies,prediction and harness of sandstorms in China.
文摘The English edition of China Daily on 13 September 2017 had a story(page 12) sponsored by the State Forestry Administration, which ran a campaign against desertification: The Songhe villager, Shi Shuzhu(with photo) of Minqin County, Gansu Province, describes the collective effort to build a 9-kilometre long ‘green wall’ to keep the desert out, declaring that ‘respecting science and technology for its useful new methods is something I have learned from long periods of struggling with sandstorms’.
基金supported by National Key R&D Program of China(No.2017YFC0212403).
文摘Mineral dust particles play an important role in the formation of secondary inorganic aerosols, which largely contribute to haze pollution in China.During this study, a haze episode(haze days) and a typical haze process mixed with sandstorm(sandy haze days)were observed in Zhengzhou with a series of high-time-resolution monitoring instruments from November 22 to December 8, 2018.Concentrations of PM10 and crustal elements clearly increased in the sandy haze days.Concentrations of gaseous pollutants, metallic elements emitted from anthropogenic sources, nitrate, and ammonium during sandy haze days were slightly lower than those during the haze days but still obviously higher than those during the non-haze days.The sulfate concentrations, the sulfate fractions in PM2.5,and the sulfur oxidation ratios significantly increased in the sandy haze days.Heterogeneous reactions dominated the conversion of SO2 during the haze and sandy haze days.Enhanced SO2 conversion during the sandy haze days may be attributed to the high concentrations of transition metal ions from the sandstorm when the values of relative humidity(RH) were in 30%–70%, and high O3 at certain time points.Gas-phase NO2 oxidation reactions were the main pathways for nitrate formation.In the sandy haze days,higher nitrogen oxidation ratio(NOR) at daytime may be associated with higher RH and lower temperature than those in the haze days, which facilitate the gas-to-particle partitioning of nitrate;higher NOR values at night may be attributed to the higher O3 concentrations, which promoted the formation of N2O5.
基金The Knowledge Innovation Programof the Chinese Academy of Sciences(No. KZCX3-SW-341) and the Cold and Arid Environmental and EngineeringResearchInstitute(No.2004105)
文摘The purpose of this present study is to investigate the frequency and variation of sandstorm in Minqin Oasis. Using daily observational data of sandstorm and other meteorologic data from 1954 to 2000, we have illuminated the relationship between sandstorm, meteorological parameters and human activities. The results of the analysis show that the highest frequency of sandstorms occurrence and their duration mainly focus on March, April and May, especially in April. Most of sandstorms occur from midday to nightfall, but relative few appear from midnight to forenoon, which apparently correlates to the daily variations of atmospheric thermal stability within atmospheric boundary layer. Monthly mean and annual mean duration of sandstorms coincide well with the frequencies of sandstorm occurrence.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060600)Knowledge Innovation Programs of Chinese Academy of Sciences(No.KSCX2-EW-J-5)National Key Technology Research and Development Program of China(No.2011BAD31B02)
文摘Land use change is one of the major factors that affect soil organic carbon （SOC） variation and global carbon balance. However, the effects of land use change on SOC are always variable. In this study, using a series of paired-field experiments, we estimated the effects of revegetation types and environmental conditions on SOC stock and vertical distribution after replacement of cropland with poplar （Populus tomentosa） and korshinsk peashrub （Caragana korshinskt＇i） in three climate regions （Chifeng City, Fengning City and Datong City of the ＇Beijing-Tianjin Sandstorm Source Control＇ （BTSSC） program area. The results show that SOC sequestration rate ranges from 0.15 Mg/（ha-yr） to 3.76 Mg/（ha-yr） in the soil layer of 0-100 cm in early stage after cropland afforestation in the BTSSC program area. The SOC accumulation rates are the highest in Fengning for both the two vegetation types. Compared to C. korshinskii, P tomentosa has greater effects on SOC accumulation in the three climate regions, but significantly greater effect only appears in Datong. The SOC density increases by 20%-111% and 15%-59% for P. tomentosa and 9%-63% and 0-73% for C. korshinskii in the 0-20 cm and 20-100 cm soil layers, respectively. Our results indicate that cropland afforestation not only affects SOC stock in the topsoil, but also has some effects on subsoil carbon. However, the effect of cropland afforestation on SOC accumulation varied with climate regions and revegetation types. Considering the large area of revegetation and relatively high SOC accumulation rate, SOC sequestration in the BTSSC program should contribute significantly to decrease the CO2 concentration in the atmosphere.
