Total concentrations of arsenic, lead, cadmium, mercury, nickel, chromium, and copper in the soils from near a coal mine area in southwest Guizhou, China, were measured to evaluate the level of contamination, and the ...Total concentrations of arsenic, lead, cadmium, mercury, nickel, chromium, and copper in the soils from near a coal mine area in southwest Guizhou, China, were measured to evaluate the level of contamination, and the potential ecological risks posed by the heavy metals were quantitatively estimated. Results reveal that all heavy metals/metalloid exceeded the background values for soil environmental quality of heavy metals in Guizhou area. Geo-accumulation index(I_(geo)) showed that arsenic had the highest contamination level(I_(geo)=4) among the seven heavy metals/metalloid, and the contamination levels of mercury and lead were also relatively high(I_(geo)=3). Pearson correlation and cluster analysis identified that mercury, copper and arsenic had a relationship, and their presence might be mainly related to mining activity, coal and oil combustion, and vehicle emissions. Improved Nemerow index indicated that the overall level of heavy metal contamination in the studied area ranged from moderately–heavily contaminated to heavily contaminated level. Potential ecological risk index(R_I) analysis manifested that the whole ecological risk level ranged from high degree to very high degree(325.30≤R_I≤801.02) in the studied soil samples, and the potential ecological risk factors (E_r^i) of heavy metals/metalloid were as follows: Hg > As > Cd > Pb > Cu > Ni > Cr, and the E_r^i of Hg and As reached very high risk grade.展开更多
The Virginian: A Horseman of the Plains (1902) has been considered as one of the masterpieces of American western novels for its successful depiction of cowboys and local customs, which earns Owen Wister the Father...The Virginian: A Horseman of the Plains (1902) has been considered as one of the masterpieces of American western novels for its successful depiction of cowboys and local customs, which earns Owen Wister the Father of Western fiction. The paper aims to reveal the relationship between The Virginian and its historical context by applying the doctrines of New Historicism: historicity of texts and textuality of history. By historicity of texts, it points out that the work is the emblem of disappearance of western frontier, and it symbolizes the union of the Wild West and the civilized east. By textuality of history, it detects the change of social class, the development of livestock industry and railway, and their influence on the work at the later part of 19th century.展开更多
This study has examined the temporal variation in monthly, seasonal & annual precipitation over the Western Himalayan Region(WHR) and the influence of global teleconnections, like the North Atlantic Oscillation(NA...This study has examined the temporal variation in monthly, seasonal & annual precipitation over the Western Himalayan Region(WHR) and the influence of global teleconnections, like the North Atlantic Oscillation(NAO) and Southern Oscillation(SO) Indices on seasonal & annual precipitation. The Mann–Kendall non-parametric test is applied for trend detection and the Pettitt–Mann–Whitney test is used to detect possible shift. Maximum entropy spectral analysis is applied to find the periodicity in annual & seasonal precipitation. The study shows a non-significant decreasing trend in annual precipitation over WHR for the period 1857-2006. However, in seasonal precipitation, a significant decreasing trend is observed in monsoon and a significant increasing trend in post-monsoon season during the same period. The significant decrease in monsoon precipitation may be due to weakening of its teleconnection with NAO as well as SO Indices mainly during last three decades. It is observed that the probable change of year in annual & monsoon precipitation over WHR is 1979. The study also shows significant periodicities of 2.3-2.9 years and of 3.9-4.7 years in annual & seasonal precipitation over WHR.展开更多
This paper studies how different cultural values and rhetorical traditions may influence students' perceptions and understanding of effective ethos in persuasive essays. Fifty Chinese EFL (English as a foreign langu...This paper studies how different cultural values and rhetorical traditions may influence students' perceptions and understanding of effective ethos in persuasive essays. Fifty Chinese EFL (English as a foreign language) college students and 50 American college students participated in writing English persuasive essays on the selected topics. The essays were then compared for similarities and differences in the use of rhetorical appeals with a focus on ethos, the credibility, and trustworthiness of an author. The study revealed that participants from both groups established ethos as an important rhetorical tool to persuade the audience to accept their viewpoints. However, they displayed different perceptions of what effective ethos entailed. For Chinese participants, effective ethos seemed to come from using detailed explanations that reflected an author's intention to advocate an ethical or moral message based on some Chinese cultural values. But, strong ethos for American participants appeared to mean the use of evidence--facts and personal testimony--to establish the writer's trustworthiness. The interpretation of the results from the perspective of different cultural value orientations was also discussed.展开更多
E1 Nino events with an eastern Pacific pattern (EP) and central Pacific pattern (CP) were first separated using rotated empirical orthogonal functions (REOF). Lead/lag regression and rotated singular value decom...E1 Nino events with an eastern Pacific pattern (EP) and central Pacific pattern (CP) were first separated using rotated empirical orthogonal functions (REOF). Lead/lag regression and rotated singular value decomposition (RSVD) analyses were then carried out to study the relation between the surface zonal wind (SZW) anomalies and sea surface temperature (SST) anomalies in the tropical Pacific. A possible physical process for the CP E1 Nifio was proposed. For the EP E1 Nino, strong westerly anomalies that spread eastward continuously produce an anomalous ocean zonal convergence zone (ZCZ) centered on about 165°W. This SZW anomaly pattern favors poleward and eastward Sverdrup transport at the equator. For the CP E1Nino, westerly anomalies and the ZCZ are mainly confined to the western Pacific, and easterly anomalies blow in the eastern Pacific. This SZW anomaly pattern restrains poleward and eastward Sverdrup transport at the equator; however, there is an eastward Sverdrup transport at about 5°N, which favors the wanning of the north-eastern tropical Pacific. It is found that the slowness of eastward propagation of subsurface warm water (partly from the downwelling caused by Ekman convergence and the ZCZ) is due to the slowdown of the undercurrent in the central basin, and vertical advection in the central Pacific may be important in the formation and disappearance of the CP E1 Nifio.展开更多
The characteristics of haze days and the climatic background are analyzed by using daily observations of haze,precipitation,mean and maximum wind speed of 664 meteorological stations for the period of 1961–2012.The r...The characteristics of haze days and the climatic background are analyzed by using daily observations of haze,precipitation,mean and maximum wind speed of 664 meteorological stations for the period of 1961–2012.The results show that haze days occur significantly more often in eastern China than in western China.The annual number of haze days is 5–30 d in most parts of central-eastern China,with some areas experiencing more than 30 d,while less than 5 d are averagely occurring in western China.Haze days are mainly concentrated in the winter half-year,with most in winter,followed by autumn,spring,and then summer.Nearly 20%of annual haze days are experienced in December.The haze days in central-eastern China in the winter half-year have a significant increasing trend of 1.7 d per decade during 1961–2012.There were great increases in haze days in the 1960s,1970s and the beginning of the 21st century.There was also significant abrupt changes of haze days in the early 1970s and 2000s.From 1961 to 2012,haze days in the winter half-year increased in South China,the middle-lower reaches of the Yangtze River,and North China,but decreased in Northeast China,eastern Northwest China and eastern Southwest China.The number of persistent haze is rising.The Longer the haze,the greater the proportion to the number persistent haze.Certain climatic conditions exacerbated the occurrence of haze.The correlation coefficient between haze days and precipitation days in the winter half-year is mainly negative in central-eastern China.The precipitation days show a decreasing trend in most parts of China,with a rate of around–4.0 d per decade in central-eastern China,which reduces the sedimentation capacity of atmospheric pollutants.During the period of 1961–2012,the correlation coefficients between haze days and mean wind speed and strong wind days are mainly negative in central-eastern China,while there exists positive correlation between haze days and breeze days in the winter half-year.The mean wind speed and strong wind days are decreasing,while breeze days are increasing in most parts of China,which is benefitial to the reduction of the pollutants diffusion capacity.As a result,haze occurs more easily.展开更多
The trend of transferring eastern textile industry to western regions in China is increasingly obvious.As for Sichuan Province,it is a chance to promote economic development and upgrade the textile industry through th...The trend of transferring eastern textile industry to western regions in China is increasingly obvious.As for Sichuan Province,it is a chance to promote economic development and upgrade the textile industry through the incident compared with the other western regions.This paper analyzes the risk to environment in Sichuan Province when accepting the transfer and puts forwards relevant measures to this point.展开更多
Gas disasters always restrict the tunnel constructions in mountain area, which becomes a major geological barrier against the development of underground engineering. China is rich in coal resources and has a large amo...Gas disasters always restrict the tunnel constructions in mountain area, which becomes a major geological barrier against the development of underground engineering. China is rich in coal resources and has a large amount of gas with a wide range of distribution. However, China experienced not only adverse effects on coal mining but also gas disasters in underground engineering construction, such as tunnels and chambers. With the increased number of tunnels passing through coal-bearing strata, the incidence of gas accidents is also rising. Therefore, the significance of preventing and mitigating gas disasters should be emphasized, and an effective risk assessment method for gas disasters should be established. On the basis of research on over 100 gas tunnels in China, a relatively ideal gas disaster risk assessment method and system for tunnels are established through the following measures. Firstly, geo-environmental conditions and gas situations were analyzed during construction. Secondly, qualitative analysis was combined with quantitative analysis. Finally, the influencing factors of gas disasters, including geological conditions, gas,and human factors, were investigated. The gas tunnel risk assessment system includes three levels:(1) the grading assessment of a gas tunnel during the planning stage,(2) the risk assessment of gas tunnel construction during the design and construction stages,(3) the gas tunnel outburst risk assessment during the coal uncovering stage. This system was applied to the dynamic assessment of gas disaster during the construction of the Zipingpu tunnel of Dujiangyan–Wenchuan Highway(in Sichuan, Southwest China). The assessment results were consistent with the actual excavation, which verified the rationality and feasibility of the system. The developed system was believed to be back-up and applied for risk assessment of gas disaster in the underground engineering construction.展开更多
A numerical model for simulating storm surge with nested grid system has been applied to hindcast the coastal flooding on both sides of Taiwan Strait. The simulation results can be used to understand the transport var...A numerical model for simulating storm surge with nested grid system has been applied to hindcast the coastal flooding on both sides of Taiwan Strait. The simulation results can be used to understand the transport variation and the inundation distribution induced by the storm surge on the interested area during typhoon invades. The case in this study is Typhoon SEPAT, which passed through central Taiwan in 2007. The transport characteristics through Taiwan Strait under the influence of Typhoon SEPAT were discussed by comparing the field observations and numerical simulations during the typhoon period. The results indicate that the surge height of Typhoon SEPAT did not respond to the peak of wind waves accompanied with 15 hrs time lag. According to the influence of dynamical forces on the storm surge in Taiwan Strait, the onshore wind is the dominant role of coastal inundation during this typhoon event in Taiwan Strait. By observing the inundation map through the typhoon period, the coasts of Yulin County are verified to be the most serious affected area in the vicinity of Taiwan Strait.展开更多
This paper investigates the variability of the summer (May-September) South Asian Iligh (SAIl) for the period 1979-2012. Results show that the intensity and the area of the summer SAH decreased around 2002 at the ...This paper investigates the variability of the summer (May-September) South Asian Iligh (SAIl) for the period 1979-2012. Results show that the intensity and the area of the summer SAH decreased around 2002 at the decadal scale; and the East Asian westerly jet suppressed at the north edge of the SAH, which is consistent with the SAH variation. The precipitation pattern over eastern China also shifted during the same periods, with increased rainfall in the Huang-Huai River region and South China and decreased rainfall in the Yangtze River region. The relationship between the two variations is evidently strengthened via changes in moisture flux.展开更多
In this study, weather condition data such as the monthly average temperature, relative moisture, wind speed, pressure and the calculated wind power values of Zonguldak, Sinop, Dtizce, Bartm, Kastamonu, Bolu and Karab...In this study, weather condition data such as the monthly average temperature, relative moisture, wind speed, pressure and the calculated wind power values of Zonguldak, Sinop, Dtizce, Bartm, Kastamonu, Bolu and Karabi^k cities located in western Black Sea region were examined for 10 year period (2001-2011). In the modeling of the weather conditions, linear regression analysis was used and the effect of temperature, relative moisture and pressure on wind speed was researched by non-linear regression method. Besides, in this study, the effect of roughness coefficient in cities of western Black Sea region was also taken into consideration and the wind power potentials in 10 m, 25 m and 50 m altitude were researched in detail with the help of WASP (Wind Atlas Analysis and Application) program. In the light of the values obtained by developed models and weather condition data, it was observed that some cities in the western Black Sea region have wind power potential with their effects on environment and energy.展开更多
Changes in the vegetation and climate of the westerly-dominated areas in Central Asia during the Holocene were interpreted using pollen-assemblages and charcoal data from a 300-cm-long sediment core of the Sayram Lake...Changes in the vegetation and climate of the westerly-dominated areas in Central Asia during the Holocene were interpreted using pollen-assemblages and charcoal data from a 300-cm-long sediment core of the Sayram Lake,northern Xinjiang.Accele-rator Mass Spectrometry(AMS) radiocarbon dating methods were applied to bulk organic matter of the samples.Artemisia spp./Chenopodiaceae ratios and results from principal component analysis were used to infer that the lake basin was dominated by desert vegetation before ca.9.6 cal.ka BP,which suggests a warm and dry climate in the early Holocene.Desert steppe/steppe expanded during 9.6-5.5 cal.ka BP,indicating a remarkable increase both in the precipitation and temperature during the mid-Holocene.Desert vegetation dominated between 6.5 and 5.5 cal.ka BP,marking an extreme warmer and drier interval.The steppe/meadow steppe recovered,and temperatures decreased from 5.5 cal.ka BP in the late Holocene,as indicated by the increased abundance of Artemisia and the development of meadows.Holocene temperatures and moisture variations in the Sayram Lake areas were similar to those of adjacent areas.This consistency implies that solar radiation was the main driving factor for regional temperature changes,and that the effect of temperature variations was significant on regional changes in humidity.The evolution of climate and environment in the Sayram Lake areas,which were characterized as dry in the early Holocene and relatively humid in the middle-late Holocene,are clearly different from those in monsoonal areas.Dry conditions in the early Holocene in the Sayram Lake areas were closely related to decreased water vapor advection.These conditions were a result of reduced westerly wind speeds and less evaporation upstream,which in turn were caused by seasonal changes in solar radiation superimposed by strong evaporation following warming and drying local climate.展开更多
The geomorphic evolution of northwestern China during the Cenozoic has been a subject of much geological interest because of its link with the uplift of the Himalayan-Tibetan complex.Much information about these chang...The geomorphic evolution of northwestern China during the Cenozoic has been a subject of much geological interest because of its link with the uplift of the Himalayan-Tibetan complex.Much information about these changes is recoverable from the sedimentary sequences of the region.We report here on the thick eolian deposits mantling the Huajialing Mountains,a relatively flat mountain range in the western Loess Plateau.Correlation of magnetic susceptibility stratigraphy with the QA-I Miocene eolian sequence dates a 134.7 m section(NL-VII) for the interval from 18.7 to 11.8 Ma,as confirmed by micro-mammalian fossils.These eolian deposits demonstrate a much wider distribution of the Miocene eolian deposits,and also indicate that the topography contrasts in the western Loess Plateau,including the uplifts of the Huajialing Mountains and the bedrock highlands in the Qinan region,were formed by the early Miocene.The near-continuous Miocene eolian sequence from 18.7 to 11.8 Ma indicates that the substratum of Huajialing had not experienced any intense tectonic changes during this time interval,which suggests further,the relative tectonic stability of the nearby Tibetan Plateau.展开更多
基金Project(21467005)supported by the National Natural Science Foundation of China
文摘Total concentrations of arsenic, lead, cadmium, mercury, nickel, chromium, and copper in the soils from near a coal mine area in southwest Guizhou, China, were measured to evaluate the level of contamination, and the potential ecological risks posed by the heavy metals were quantitatively estimated. Results reveal that all heavy metals/metalloid exceeded the background values for soil environmental quality of heavy metals in Guizhou area. Geo-accumulation index(I_(geo)) showed that arsenic had the highest contamination level(I_(geo)=4) among the seven heavy metals/metalloid, and the contamination levels of mercury and lead were also relatively high(I_(geo)=3). Pearson correlation and cluster analysis identified that mercury, copper and arsenic had a relationship, and their presence might be mainly related to mining activity, coal and oil combustion, and vehicle emissions. Improved Nemerow index indicated that the overall level of heavy metal contamination in the studied area ranged from moderately–heavily contaminated to heavily contaminated level. Potential ecological risk index(R_I) analysis manifested that the whole ecological risk level ranged from high degree to very high degree(325.30≤R_I≤801.02) in the studied soil samples, and the potential ecological risk factors (E_r^i) of heavy metals/metalloid were as follows: Hg > As > Cd > Pb > Cu > Ni > Cr, and the E_r^i of Hg and As reached very high risk grade.
文摘The Virginian: A Horseman of the Plains (1902) has been considered as one of the masterpieces of American western novels for its successful depiction of cowboys and local customs, which earns Owen Wister the Father of Western fiction. The paper aims to reveal the relationship between The Virginian and its historical context by applying the doctrines of New Historicism: historicity of texts and textuality of history. By historicity of texts, it points out that the work is the emblem of disappearance of western frontier, and it symbolizes the union of the Wild West and the civilized east. By textuality of history, it detects the change of social class, the development of livestock industry and railway, and their influence on the work at the later part of 19th century.
文摘This study has examined the temporal variation in monthly, seasonal & annual precipitation over the Western Himalayan Region(WHR) and the influence of global teleconnections, like the North Atlantic Oscillation(NAO) and Southern Oscillation(SO) Indices on seasonal & annual precipitation. The Mann–Kendall non-parametric test is applied for trend detection and the Pettitt–Mann–Whitney test is used to detect possible shift. Maximum entropy spectral analysis is applied to find the periodicity in annual & seasonal precipitation. The study shows a non-significant decreasing trend in annual precipitation over WHR for the period 1857-2006. However, in seasonal precipitation, a significant decreasing trend is observed in monsoon and a significant increasing trend in post-monsoon season during the same period. The significant decrease in monsoon precipitation may be due to weakening of its teleconnection with NAO as well as SO Indices mainly during last three decades. It is observed that the probable change of year in annual & monsoon precipitation over WHR is 1979. The study also shows significant periodicities of 2.3-2.9 years and of 3.9-4.7 years in annual & seasonal precipitation over WHR.
文摘This paper studies how different cultural values and rhetorical traditions may influence students' perceptions and understanding of effective ethos in persuasive essays. Fifty Chinese EFL (English as a foreign language) college students and 50 American college students participated in writing English persuasive essays on the selected topics. The essays were then compared for similarities and differences in the use of rhetorical appeals with a focus on ethos, the credibility, and trustworthiness of an author. The study revealed that participants from both groups established ethos as an important rhetorical tool to persuade the audience to accept their viewpoints. However, they displayed different perceptions of what effective ethos entailed. For Chinese participants, effective ethos seemed to come from using detailed explanations that reflected an author's intention to advocate an ethical or moral message based on some Chinese cultural values. But, strong ethos for American participants appeared to mean the use of evidence--facts and personal testimony--to establish the writer's trustworthiness. The interpretation of the results from the perspective of different cultural value orientations was also discussed.
基金Supported by the National Natural Science Foundation of China(Nos.41076010,41206017)the National Basic Research Program of China(973 Program)(No.2012CB417402)
文摘E1 Nino events with an eastern Pacific pattern (EP) and central Pacific pattern (CP) were first separated using rotated empirical orthogonal functions (REOF). Lead/lag regression and rotated singular value decomposition (RSVD) analyses were then carried out to study the relation between the surface zonal wind (SZW) anomalies and sea surface temperature (SST) anomalies in the tropical Pacific. A possible physical process for the CP E1 Nifio was proposed. For the EP E1 Nino, strong westerly anomalies that spread eastward continuously produce an anomalous ocean zonal convergence zone (ZCZ) centered on about 165°W. This SZW anomaly pattern favors poleward and eastward Sverdrup transport at the equator. For the CP E1Nino, westerly anomalies and the ZCZ are mainly confined to the western Pacific, and easterly anomalies blow in the eastern Pacific. This SZW anomaly pattern restrains poleward and eastward Sverdrup transport at the equator; however, there is an eastward Sverdrup transport at about 5°N, which favors the wanning of the north-eastern tropical Pacific. It is found that the slowness of eastward propagation of subsurface warm water (partly from the downwelling caused by Ekman convergence and the ZCZ) is due to the slowdown of the undercurrent in the central basin, and vertical advection in the central Pacific may be important in the formation and disappearance of the CP E1 Nifio.
基金supported by the National Basic Research Program of China(No.2012CB955902)
文摘The characteristics of haze days and the climatic background are analyzed by using daily observations of haze,precipitation,mean and maximum wind speed of 664 meteorological stations for the period of 1961–2012.The results show that haze days occur significantly more often in eastern China than in western China.The annual number of haze days is 5–30 d in most parts of central-eastern China,with some areas experiencing more than 30 d,while less than 5 d are averagely occurring in western China.Haze days are mainly concentrated in the winter half-year,with most in winter,followed by autumn,spring,and then summer.Nearly 20%of annual haze days are experienced in December.The haze days in central-eastern China in the winter half-year have a significant increasing trend of 1.7 d per decade during 1961–2012.There were great increases in haze days in the 1960s,1970s and the beginning of the 21st century.There was also significant abrupt changes of haze days in the early 1970s and 2000s.From 1961 to 2012,haze days in the winter half-year increased in South China,the middle-lower reaches of the Yangtze River,and North China,but decreased in Northeast China,eastern Northwest China and eastern Southwest China.The number of persistent haze is rising.The Longer the haze,the greater the proportion to the number persistent haze.Certain climatic conditions exacerbated the occurrence of haze.The correlation coefficient between haze days and precipitation days in the winter half-year is mainly negative in central-eastern China.The precipitation days show a decreasing trend in most parts of China,with a rate of around–4.0 d per decade in central-eastern China,which reduces the sedimentation capacity of atmospheric pollutants.During the period of 1961–2012,the correlation coefficients between haze days and mean wind speed and strong wind days are mainly negative in central-eastern China,while there exists positive correlation between haze days and breeze days in the winter half-year.The mean wind speed and strong wind days are decreasing,while breeze days are increasing in most parts of China,which is benefitial to the reduction of the pollutants diffusion capacity.As a result,haze occurs more easily.
文摘The trend of transferring eastern textile industry to western regions in China is increasingly obvious.As for Sichuan Province,it is a chance to promote economic development and upgrade the textile industry through the incident compared with the other western regions.This paper analyzes the risk to environment in Sichuan Province when accepting the transfer and puts forwards relevant measures to this point.
基金support by the National Natural Science Foundation of China (Grant No. 41302244)
文摘Gas disasters always restrict the tunnel constructions in mountain area, which becomes a major geological barrier against the development of underground engineering. China is rich in coal resources and has a large amount of gas with a wide range of distribution. However, China experienced not only adverse effects on coal mining but also gas disasters in underground engineering construction, such as tunnels and chambers. With the increased number of tunnels passing through coal-bearing strata, the incidence of gas accidents is also rising. Therefore, the significance of preventing and mitigating gas disasters should be emphasized, and an effective risk assessment method for gas disasters should be established. On the basis of research on over 100 gas tunnels in China, a relatively ideal gas disaster risk assessment method and system for tunnels are established through the following measures. Firstly, geo-environmental conditions and gas situations were analyzed during construction. Secondly, qualitative analysis was combined with quantitative analysis. Finally, the influencing factors of gas disasters, including geological conditions, gas,and human factors, were investigated. The gas tunnel risk assessment system includes three levels:(1) the grading assessment of a gas tunnel during the planning stage,(2) the risk assessment of gas tunnel construction during the design and construction stages,(3) the gas tunnel outburst risk assessment during the coal uncovering stage. This system was applied to the dynamic assessment of gas disaster during the construction of the Zipingpu tunnel of Dujiangyan–Wenchuan Highway(in Sichuan, Southwest China). The assessment results were consistent with the actual excavation, which verified the rationality and feasibility of the system. The developed system was believed to be back-up and applied for risk assessment of gas disaster in the underground engineering construction.
文摘A numerical model for simulating storm surge with nested grid system has been applied to hindcast the coastal flooding on both sides of Taiwan Strait. The simulation results can be used to understand the transport variation and the inundation distribution induced by the storm surge on the interested area during typhoon invades. The case in this study is Typhoon SEPAT, which passed through central Taiwan in 2007. The transport characteristics through Taiwan Strait under the influence of Typhoon SEPAT were discussed by comparing the field observations and numerical simulations during the typhoon period. The results indicate that the surge height of Typhoon SEPAT did not respond to the peak of wind waves accompanied with 15 hrs time lag. According to the influence of dynamical forces on the storm surge in Taiwan Strait, the onshore wind is the dominant role of coastal inundation during this typhoon event in Taiwan Strait. By observing the inundation map through the typhoon period, the coasts of Yulin County are verified to be the most serious affected area in the vicinity of Taiwan Strait.
基金supported by the National Natural Science Foundation of China (Grants Nos. 41210007 and 41130103)
文摘This paper investigates the variability of the summer (May-September) South Asian Iligh (SAIl) for the period 1979-2012. Results show that the intensity and the area of the summer SAH decreased around 2002 at the decadal scale; and the East Asian westerly jet suppressed at the north edge of the SAH, which is consistent with the SAH variation. The precipitation pattern over eastern China also shifted during the same periods, with increased rainfall in the Huang-Huai River region and South China and decreased rainfall in the Yangtze River region. The relationship between the two variations is evidently strengthened via changes in moisture flux.
文摘In this study, weather condition data such as the monthly average temperature, relative moisture, wind speed, pressure and the calculated wind power values of Zonguldak, Sinop, Dtizce, Bartm, Kastamonu, Bolu and Karabi^k cities located in western Black Sea region were examined for 10 year period (2001-2011). In the modeling of the weather conditions, linear regression analysis was used and the effect of temperature, relative moisture and pressure on wind speed was researched by non-linear regression method. Besides, in this study, the effect of roughness coefficient in cities of western Black Sea region was also taken into consideration and the wind power potentials in 10 m, 25 m and 50 m altitude were researched in detail with the help of WASP (Wind Atlas Analysis and Application) program. In the light of the values obtained by developed models and weather condition data, it was observed that some cities in the western Black Sea region have wind power potential with their effects on environment and energy.
基金supported by National Natural Science Foundation of China(Grant No.40802084)International Science&Technology Cooperation Program of China(Grant No.2011DFA21240)the CAS/SAFEA International Partnership Program for Creative Research Teams(Grant No.KZZDEW-TZ-08)
文摘Changes in the vegetation and climate of the westerly-dominated areas in Central Asia during the Holocene were interpreted using pollen-assemblages and charcoal data from a 300-cm-long sediment core of the Sayram Lake,northern Xinjiang.Accele-rator Mass Spectrometry(AMS) radiocarbon dating methods were applied to bulk organic matter of the samples.Artemisia spp./Chenopodiaceae ratios and results from principal component analysis were used to infer that the lake basin was dominated by desert vegetation before ca.9.6 cal.ka BP,which suggests a warm and dry climate in the early Holocene.Desert steppe/steppe expanded during 9.6-5.5 cal.ka BP,indicating a remarkable increase both in the precipitation and temperature during the mid-Holocene.Desert vegetation dominated between 6.5 and 5.5 cal.ka BP,marking an extreme warmer and drier interval.The steppe/meadow steppe recovered,and temperatures decreased from 5.5 cal.ka BP in the late Holocene,as indicated by the increased abundance of Artemisia and the development of meadows.Holocene temperatures and moisture variations in the Sayram Lake areas were similar to those of adjacent areas.This consistency implies that solar radiation was the main driving factor for regional temperature changes,and that the effect of temperature variations was significant on regional changes in humidity.The evolution of climate and environment in the Sayram Lake areas,which were characterized as dry in the early Holocene and relatively humid in the middle-late Holocene,are clearly different from those in monsoonal areas.Dry conditions in the early Holocene in the Sayram Lake areas were closely related to decreased water vapor advection.These conditions were a result of reduced westerly wind speeds and less evaporation upstream,which in turn were caused by seasonal changes in solar radiation superimposed by strong evaporation following warming and drying local climate.
基金supported by National Natural Science Foundation of China (Grant No. 40730104)Chinese Academy of Sciences (Grant Nos. KZCX2-YW-Q1-15 and KZCX2-YW-117)
文摘The geomorphic evolution of northwestern China during the Cenozoic has been a subject of much geological interest because of its link with the uplift of the Himalayan-Tibetan complex.Much information about these changes is recoverable from the sedimentary sequences of the region.We report here on the thick eolian deposits mantling the Huajialing Mountains,a relatively flat mountain range in the western Loess Plateau.Correlation of magnetic susceptibility stratigraphy with the QA-I Miocene eolian sequence dates a 134.7 m section(NL-VII) for the interval from 18.7 to 11.8 Ma,as confirmed by micro-mammalian fossils.These eolian deposits demonstrate a much wider distribution of the Miocene eolian deposits,and also indicate that the topography contrasts in the western Loess Plateau,including the uplifts of the Huajialing Mountains and the bedrock highlands in the Qinan region,were formed by the early Miocene.The near-continuous Miocene eolian sequence from 18.7 to 11.8 Ma indicates that the substratum of Huajialing had not experienced any intense tectonic changes during this time interval,which suggests further,the relative tectonic stability of the nearby Tibetan Plateau.