The Yichang section of the Three Gorges of the Yangtze River boasts abundant cultural resources and historical heritage.Thorough exploration and development of these cultural tourism resources,combined with the creati...The Yichang section of the Three Gorges of the Yangtze River boasts abundant cultural resources and historical heritage.Thorough exploration and development of these cultural tourism resources,combined with the creation of a unique cultural tourism identity for this section,can not only invigorate the development of the region’s tourism industry but also contribute significantly to cultural preservation and transmission.This study examines the development and current state of cultural tourism in the Three Gorges of the Yangtze River,focusing specifically on the Yichang section.Using the SWOT analysis method,it offers an in-depth analysis and proposes suggestions for cultural tourism development in this area,aiming to provide a reference for future tourism development strategies in the region.展开更多
It is well known that, in most cases, soil water doesn't move in the form of laminar flow as described by Darcy law. Only when Reynolds number ( Re ) is no more than 10, does water movement follow Darcy law. A s...It is well known that, in most cases, soil water doesn't move in the form of laminar flow as described by Darcy law. Only when Reynolds number ( Re ) is no more than 10, does water movement follow Darcy law. A soil profile with 2 9 m long and 2 13 2 60 m deep was excavated on a lower slope located at Zigui County, Hubei Province, China. Field observation found that soil pipes were mainly distributed in the transient layer between horizon B with higher degree of granite weathering and horizon C with lower degree of granite weathering. At the foot of the slope, about 5 7 soil pipes per meter were observed along the vertical direction of the slope. The observed results, obtained by continuous observation of soil pipes and pipe flow processes at granite slope for many rainfall events, indicate that the relationship between velocity of pipe flow and hydraulic gradient along the pipe is parabolic rather than linear. Based on the investigated data of soil, landform, and land use etc., combined with observed data of pipe flow derived from many rainfall events, a pipe flow model was developed. For velocity V p, discharge Q p of pipe flow and radius r of soil pipe, great similarity was found between simulated and observed values. Particularly, the simulated length of soil pipes reflects the great difference among soil pipes as a result of its different position in the soil profile. The length values of 4 soil pipes were estimated to be 98 1%, 27 6%, 11 0% and 3 0% of the longest distance of the catchment, respectively. As a special case of water movement, soil pipe flow follows Darcy Weisbach law. Discharge of pipe flow is much greater than infiltration discharge in common. Only when the depth of groundwater is more than the diameter of soil pipe and water layer submerges soil pipes during rainfall, may pipe flow occur. Under these circumstances, discharge of pipe flow is directly proportional to the depth of groundwater.展开更多
The Three Gorges Project(TGP)has changed the flow-sediment process in the middle Yangtze River.For navigation purposes,there is an urgent need to study the changes of the river regime over a long-term period and the s...The Three Gorges Project(TGP)has changed the flow-sediment process in the middle Yangtze River.For navigation purposes,there is an urgent need to study the changes of the river regime over a long-term period and the shoal-channel evolution over different seasons since the completion of the TGP.Based on analysis of the measured data and the results of a two-dimensional mathematical model,the changes of the river regime and river bed evolution in the Yaojian reach downstream of the TGP were studied.Results show that a high sediment transport flux helps to keep the main flow in the North Branch,while a low sediment transport flux helps to keep the main flow in the South Branch.Thus,the main branch will not change in the near future because of the low sediment transport load.In this study,the flow-sediment process adjusted by the TGP was restored to the conditions before the TGP,and the river bed evolution under the adjusted and non-adjusted flow-sediment conditions was calculated.After the completion of the TGP,the reservoir storage accelerated the flood recession process and decreased the erosion by 11.9%under the flow-sediment conditions in 2010,and the deposition in the flood season decreased by 56.4%.展开更多
This report provides a broad overview of the climate and the major weather and climate events over the Three Gorges Region of the Yangtze River(TGR)in 2019.The year 2019,a 0.3℃ warmer year than normal,had a colder wi...This report provides a broad overview of the climate and the major weather and climate events over the Three Gorges Region of the Yangtze River(TGR)in 2019.The year 2019,a 0.3℃ warmer year than normal,had a colder winter and warmer spring,summer,and autumn.Annual precipitation in 2019 was 13%less than normal.Below average normal rainfall amounts were received in all four seasons,with 28%and 16%less-than-normal in winter and summer,respectively.The annual mean wind speed in the TGR was higher than normal,and relative humidity was near normal for all four seasons.The intensity of acid rain in 2019 was the weakest since 1999.The major climate events and meteorological disasters in the TGR in 2019 included heat waves,drought,and rainstorms.Heat waves occurred frequently and persisted for long durations.Summer and autumn drought occurred in central and eastern regions of the TGR.The autumn rains of West China occurred earlier this year,which brought much more rainfall than normal in central and western regions of the TGR.展开更多
This report provides a summary of the climate, as well as the major weather and climate events,over the Three Gorges Region of the Yangtze River(TGR) in 2018. The annual mean temperature over the TGR in 2018 was 0.2℃...This report provides a summary of the climate, as well as the major weather and climate events,over the Three Gorges Region of the Yangtze River(TGR) in 2018. The annual mean temperature over the TGR in 2018 was 0.2℃ above normal, and precipitation was near normal. Seasonal highlights included a second warmest spring in the 58-year period of records, with abundant rainfall, which resulted in the wettest March on record. Furthermore, this was the fourth-warmest summer on record in the TGR, which contributed a higher-than-normal number of hot days in2018. Precipitation was 17% and 30% less-than-normal in winter and summer, and 40% and 6% above average in spring and autumn, respectively. The annual mean wind speed in the TGR was higher than normal, and the annual mean relative humidity was near normal. The intensity of acid rain was relatively weak, being the second-weakest year since 1999. The major meteorological disaster types in the TGR include heat waves, drought, rainstorms and flooding, freezing rain, and snow. Heat waves occurred early in the summer and persisted for long durations with strong intensities. Long-term precipitation deficits resulted in drought conditions in summer 2018 across most regions of the TGR. Frequent heavy rainfall caused urban waterlogging. The early-year and late-year cold snaps were accompanied by heavy snowfall and rain over some locations across the TGR, which had adverse impacts on transportation, agriculture, electricity, and people’s lives.展开更多
In 2020,the average air temperature in the Three Gorges Region(TGR)of the Yangtze River basin was 17.2℃,which was close to normal,there were exceptionally fewer days than normal with high temperatures,and the high-te...In 2020,the average air temperature in the Three Gorges Region(TGR)of the Yangtze River basin was 17.2℃,which was close to normal,there were exceptionally fewer days than normal with high temperatures,and the high-temperature events mainly occurred in August.Meanwhile,the average precipitation was 1530.8 mm,which was a remarkable 29%more than usual,and the second-highest since 1961.The precipitation was obviously above-normal in summer,and the precipitation in both June and July was the second-highest of the same period in history.The average number of rainstorm days was higher than normal,and the second-highest since 1961.The average wind speed in the TGR was apparently higher than normal;the average relative humidity was slightly higher than normal;and there were no instances of acid rain,with the rain acidity showing a significant weakening trend over the previous 15 years.In the summer of 2020,the TGR experienced heavy rainstorms and flood disasters.Analysis shows that the frequent southward movement of cold air and abundant warm water vapor from the southwest were the direct causes of the abnormally high precipitation in the TGR from June to July.After the spring of 2020,the continuously high sea surface temperature in the Indian Ocean led to a continuously strong western Pacific subtropical high and its average location being situated more to the south than normal,which might have been an important cause for the abnormal climate conditions in the Yangtze River basin from June to July.展开更多
Objective To define and evaluate the malaria transmission potential in the Yangtze River, following construction of the Three Gorges Reservoir. Methods Six villages, namely, Kaixian, Fengjie, Wanzhou, Fuling, Yubei, a...Objective To define and evaluate the malaria transmission potential in the Yangtze River, following construction of the Three Gorges Reservoir. Methods Six villages, namely, Kaixian, Fengjie, Wanzhou, Fuling, Yubei, and Zigui were selected for investigating the malaria transmission potential in the reservoir. Transmission potential was estimated by mathematical modeling and evaluation of the local malaria situation. Factors that influenced the transmission potential were analyzed using Poisson regression analysis in combination with Grey Systematic Theory (based on evaluation by the Delphi method). Results Indirect fluorescent antibody data and the incidence of malaria in the local population were consistent with the malaria transmission potential calculated for the area. Multivariate Poisson regression analysis showed a statistically significant association between the riparian zone and the man‐biting rate. Conclusion The risk of a malaria epidemic can be forecasted using the malaria transmission potential parameters investigated here which was closely correlated with the riparian zone.展开更多
Field investigation and laboratory work reveal that inhomogeneity of the deformation of the Xiannushan fault is mainly characterized by lateral zonation, longitudinal segmentation and downward stratification. Based on...Field investigation and laboratory work reveal that inhomogeneity of the deformation of the Xiannushan fault is mainly characterized by lateral zonation, longitudinal segmentation and downward stratification. Based on these results, a 3-D deformational structure model of the fault was established and its geometrical and kinematic characteristics in two main deformational stages i.e. the main Yanshanian and Himalayan were discussed. The directions of principal and the differential stresses in these two stages were determined by using conjugate joints, striations of fault planes and microstructures of the fault zone. The direction of σI is N-S in direction with differential stresses of 150-250 MPa in the Yanshanian, and N70E with a differential stress ranging from 80-120 MPa in the Himalayan.展开更多
Objective In recent years, the birth time and evolution of the Three Gorges, Yangtze River has become a focused topic. Different from previous studies, this study used provenance analysis of Quaternary sediments to di...Objective In recent years, the birth time and evolution of the Three Gorges, Yangtze River has become a focused topic. Different from previous studies, this study used provenance analysis of Quaternary sediments to discuss this question. Among those minerals in Quaternary sediments, magnetite was rarely studied. This paper presents element geochemistry and backscatter images of detrital magnetites from the Quaternary sediments in the Yichang area of Hubei Province. By discussing the provenance changes of detratic magnetites, we suggested the birth time of the Three Gorges of the Yangtze River.展开更多
This paper summarizes the factors affecting schistosomiasis transmission in the middle and lower reaches of the Yangtze River before and after the completion of the Three Gorges Dam and analyzes schistosomiasis preval...This paper summarizes the factors affecting schistosomiasis transmission in the middle and lower reaches of the Yangtze River before and after the completion of the Three Gorges Dam and analyzes schistosomiasis prevalence trends to provide a basis for the application of the Three Gorges project methodologies in other areas.The Three Gorges Dam has demonstrated a positive effect on schistosomiasis control.Hubei,Hunan,Jiangxi,Anhui,and Jiangsu in the middle and lower reaches of the Yangtze River are currently regions with a high prevalence of schistosomiasis.These five provinces contained 97.62% of known snail areas and 93.66% of calculated schistosomiasis cases with 90.07% of counties (cities,districts) not yet meeting the criteria for schistosomiasis transmission interruption by the end of 2016.After the Three Gorges Dam was built,the prevalence of schistosomiasis in the middle and lower reaches of the Yangtze River decreased.By the end of 2016,the estimated number of cases decreased by 92.75% and the snail habitat areas decreased by 6.56% compared to 2004.No acute schistosomiasis cases have occurred for two consecutive years since 2015.展开更多
On the basis of historical earthquake data and recent observations, two grey models prediction of the next seismic active period and the maximal magnitude of earthquakes which might occur during that period are constr...On the basis of historical earthquake data and recent observations, two grey models prediction of the next seismic active period and the maximal magnitude of earthquakes which might occur during that period are constructed on the basis of the grey theory. As predicted by the two models, the next seismic active period would last 79 years, and that the maximal magnitude of earthquakes occurring within the period would not exceed 5.2. These results provide an important basis for the assessment of earthquake risks and reduction of disasters in the Three Gorges area.展开更多
A study has been made about the structural attribute of the NNW-trendingShizikou linear image belt in the head area of the reservoir of the Yangtze River Gorges and theevaluation of its crustal stability. On the basis...A study has been made about the structural attribute of the NNW-trendingShizikou linear image belt in the head area of the reservoir of the Yangtze River Gorges and theevaluation of its crustal stability. On the basis of regional geological surveys and by making astructural analysis and a multidisciplinary study, it has been ascertained that the segment withthe best displayed image characteristics is marked by a gravity gliding structure with a multilay-er gliding fold type architecture. This paper also analyzes the medium conditions, slope struc-ture and dynamic setting for the formation of the structure system.展开更多
The history of the Yangtze River is constituted by numerous river piracies that enabled the river to extend its drainage system. Two river captures are well recognized: the piracy of the Jinsha River (Jinshajiang) for...The history of the Yangtze River is constituted by numerous river piracies that enabled the river to extend its drainage system. Two river captures are well recognized: the piracy of the Jinsha River (Jinshajiang) formerly tributary of the Red River at Shigu in Yunnan Province and the Three Gorges area that linked the upper and the middle Yangtze river reaches in Hubei province. The first one is well documented, while the second, because of difficulties to retrieve datable materials and the complexity of the area geomorphology, is still quite unknown. Numerous conflicting hypotheses have been formulated to explain the pattern of river piracy, no agreement exists on the location of the drainage divide and of the point of capture;chronologies extending from the Eocene to the late Quaternary are given. Geomorphic indices can be used to examine the geomorphological and tectonic processes responsible for the development of the drainage basins. In this paper, we analyzed drainage pattern, basin shape, basin asymmetry, stream junction angle to infer the drainage of the paleorivers that were pirated, and to propose a model of the pattern of river capture based on the importance of structure, tectonic and lithological controls in the area. We showed that the Three Gorges area has been very important to the history of the Yangtze river as the piracy of the upper and middle reaches enabled the river to reach its current extend.展开更多
The giant perilous rock at Wangxia (named Wangxia perilous rock) is representative in Three Gorges of the Yangtze River, China, has threatened badly the navigation of the Yangtze River channel for a long period. The g...The giant perilous rock at Wangxia (named Wangxia perilous rock) is representative in Three Gorges of the Yangtze River, China, has threatened badly the navigation of the Yangtze River channel for a long period. The giant perilous rock is composed of siliceous limestone and argillaceous limestone, and includes two elements marking by W1 and W2, respectively. The W1 is an isolated pillar while the W2 is in clintheriform. The linking segment of dominant fissure in the W2 is composed by moniliform solution funnels at its back, and the locked segment of the dominant fissure at the base of the W2 is composed by two parts. For the locked part of the dominant fissure of the W2, the upper segment shows the same lithology with the perilous rock and it can be simplified as an elastic medium, for the lower segment composed by argillaceous shale and mudstone can be simplified as a strain-softening medium. Introducing the water-softened function, the constitutive curves with two kinds of medium materials for the locked segment in the dominant fissure of the W2 have been proposed. Based on energy principle, the cusp catastrophe model for perilous rock rupture is built and formulas for the transient elastic and impulsive acceleration and the elastic-impulsive velocity of perilous rock catastrophe rupture have been established. By the calculation, the elastic-impulsive acceleration for the catastrophe rupture of the W2 is 531.4 m/s2, while the average elastic-impulsive velocity is 2.608 m/s. Further, it is deduced that the elastic-impulsive velocity at the base of the W2 is about 5.2 m/s. For the transient ruture of the W2, there is a greater speed difference between the top and the base of the W2, which impels the giant perilous rock to be retroverted sliding rupture, coinciding with the fact. Undoubtedly, studies in this paper must play an important role to analyze the catastrophe rupture mechanism of giant perilous rocks at both banks in Three Gorges of the Yangtze River, China.展开更多
The Yangtze River has nurtured the fertile land on both its banks and hundreds of millions of Chinese people. but its raging waters have also wreaked havoc on the people living in its reaches. Since the founding of Ne...The Yangtze River has nurtured the fertile land on both its banks and hundreds of millions of Chinese people. but its raging waters have also wreaked havoc on the people living in its reaches. Since the founding of New China, large-scale surveys, planning, scientific research and feasibility studies have been carried out in an effort to harness the展开更多
The Three Gorges Project on the Yangtze River was started in December 1994. It is the largest water conservancy and hydropower project in the present world with a comprehensive result of flood prevention, generating a...The Three Gorges Project on the Yangtze River was started in December 1994. It is the largest water conservancy and hydropower project in the present world with a comprehensive result of flood prevention, generating and navigation. The reservoir can hold 22.2 billion cubic metres of water, thus being able to cut the flood flow of 27, 000 to 33, 000 cubic metres per second. Its hydropower station will have a total generating equipment capacity of 18.2 million kw with an annual generating quantity of 84.7 billion kwh to supply energy for the economic development of east China, central China and展开更多
The region around the Three Gorges project on the Yangtze River has an area of 62552 square kilometres and population of 20.14 million. It limits a range hetween the sorth-north watersheds and from Yichang of Hubei Pr...The region around the Three Gorges project on the Yangtze River has an area of 62552 square kilometres and population of 20.14 million. It limits a range hetween the sorth-north watersheds and from Yichang of Hubei Province to Jiangjin of Sichuan, including 24 cities and counties-Chongjing, Yichang and Wanxian etc. In this region, relief are mainly hills and middle-low mountains. Remote censing investigation and appraisal of land use and capacity which are two of the major restrict factors for the Three Gorges project have provided related scientific bases for macro-dicision-making of the project.展开更多
In accordance with the requirements of the National Key Technology R&D Program of the 11th "Five-year Plan", a densified seismic network consisting of 26 seismic stations was established at the Three Gorges Reservo...In accordance with the requirements of the National Key Technology R&D Program of the 11th "Five-year Plan", a densified seismic network consisting of 26 seismic stations was established at the Three Gorges Reservoir area in the section of Hubei Province in March 2009 (21 short-period seismographs, 5 broadband digital seismographs). From March to December, 2009, a total of 2,995 ML -0. 8 - 2. 9 earthquakes were detected during the trial impounding of the Three Gorges Reservoir ( water level rose from 145 m to 172.8m). Using the double difference earthquake location algorithm, 2,837 earthquakes were precisely re-located. The results show that the pattern of small local earthquake swarms in the Three Gorges Reservoir area took on a linear distribution or mass-like cluster distribution, the mass-like clusters of events were generally within a distance of 5 km from waterfront, and the linear distribution of the earthquakes could be extended to a distance of 16 km away from the waterfront. In the Hubei section of the Three Gorges Reservoir, earthquakes were mainly concentrated in the northern end of the Xiannvshan and Jiuwanxi faults near the Xiangxihe River, and along the banks of the Yangtze River at the west of Xietan township and the Shenlongxi area on the northern bank in the Badong region, with focal depths less than 10km, and 4km in average. Earthquake frequency in the reservoir region had a positive correlation with reservoir water level fluctuations, indicating that the seismicity belongs to reservoir induced earthquakes. Along the Shenlong River in the reservoir area, earthquakes showed three linear distributions in the northern Badong county, and distributed according to Karst distribution. There are underground rivers in the carbonate strata. When the reservoir was impounded, water permeated into the underground rivers, thus inducing earthquakes. Earthquakes in the areas on the crossriver segment of Xiannvshan fault, the Jiuwanxi fault and at the areas west of Xietan, Shazhen and Xizhen, may be related to the softening of discontinuities, such as the Nukou fault, the Xiannvshan fault, or the bedding joints, which would lead to failure of rock masses, thus, inducing earthquakes. However, convincing conclusions about the triggering mechanism still need further study. Additionally, near the areas south of Wenhua and Yanglin of Zigui county and at Rangkou town east of Badong county, mininginduced earthquakes occurred at the mines nearby, and on the shores of the reservoir are some collapse earthquakes.展开更多
文摘The Yichang section of the Three Gorges of the Yangtze River boasts abundant cultural resources and historical heritage.Thorough exploration and development of these cultural tourism resources,combined with the creation of a unique cultural tourism identity for this section,can not only invigorate the development of the region’s tourism industry but also contribute significantly to cultural preservation and transmission.This study examines the development and current state of cultural tourism in the Three Gorges of the Yangtze River,focusing specifically on the Yichang section.Using the SWOT analysis method,it offers an in-depth analysis and proposes suggestions for cultural tourism development in this area,aiming to provide a reference for future tourism development strategies in the region.
文摘It is well known that, in most cases, soil water doesn't move in the form of laminar flow as described by Darcy law. Only when Reynolds number ( Re ) is no more than 10, does water movement follow Darcy law. A soil profile with 2 9 m long and 2 13 2 60 m deep was excavated on a lower slope located at Zigui County, Hubei Province, China. Field observation found that soil pipes were mainly distributed in the transient layer between horizon B with higher degree of granite weathering and horizon C with lower degree of granite weathering. At the foot of the slope, about 5 7 soil pipes per meter were observed along the vertical direction of the slope. The observed results, obtained by continuous observation of soil pipes and pipe flow processes at granite slope for many rainfall events, indicate that the relationship between velocity of pipe flow and hydraulic gradient along the pipe is parabolic rather than linear. Based on the investigated data of soil, landform, and land use etc., combined with observed data of pipe flow derived from many rainfall events, a pipe flow model was developed. For velocity V p, discharge Q p of pipe flow and radius r of soil pipe, great similarity was found between simulated and observed values. Particularly, the simulated length of soil pipes reflects the great difference among soil pipes as a result of its different position in the soil profile. The length values of 4 soil pipes were estimated to be 98 1%, 27 6%, 11 0% and 3 0% of the longest distance of the catchment, respectively. As a special case of water movement, soil pipe flow follows Darcy Weisbach law. Discharge of pipe flow is much greater than infiltration discharge in common. Only when the depth of groundwater is more than the diameter of soil pipe and water layer submerges soil pipes during rainfall, may pipe flow occur. Under these circumstances, discharge of pipe flow is directly proportional to the depth of groundwater.
基金supported by the National Key Research and Development Program of China(Grants No.2016YFC0402307 and 2016YFC0402103)the National Natural Science Foundation of China(Grant No.51520105014).
文摘The Three Gorges Project(TGP)has changed the flow-sediment process in the middle Yangtze River.For navigation purposes,there is an urgent need to study the changes of the river regime over a long-term period and the shoal-channel evolution over different seasons since the completion of the TGP.Based on analysis of the measured data and the results of a two-dimensional mathematical model,the changes of the river regime and river bed evolution in the Yaojian reach downstream of the TGP were studied.Results show that a high sediment transport flux helps to keep the main flow in the North Branch,while a low sediment transport flux helps to keep the main flow in the South Branch.Thus,the main branch will not change in the near future because of the low sediment transport load.In this study,the flow-sediment process adjusted by the TGP was restored to the conditions before the TGP,and the river bed evolution under the adjusted and non-adjusted flow-sediment conditions was calculated.After the completion of the TGP,the reservoir storage accelerated the flood recession process and decreased the erosion by 11.9%under the flow-sediment conditions in 2010,and the deposition in the flood season decreased by 56.4%.
基金This study was supported by the National Key R&D Program of China[grant numbers 2017YFC1502402,2017YFD0300201,and 2017YFA0605004]the funds of comprehensive monitoring of the Three Gorges Project,which was financed by the Ministry of Water Resources of China.
文摘This report provides a broad overview of the climate and the major weather and climate events over the Three Gorges Region of the Yangtze River(TGR)in 2019.The year 2019,a 0.3℃ warmer year than normal,had a colder winter and warmer spring,summer,and autumn.Annual precipitation in 2019 was 13%less than normal.Below average normal rainfall amounts were received in all four seasons,with 28%and 16%less-than-normal in winter and summer,respectively.The annual mean wind speed in the TGR was higher than normal,and relative humidity was near normal for all four seasons.The intensity of acid rain in 2019 was the weakest since 1999.The major climate events and meteorological disasters in the TGR in 2019 included heat waves,drought,and rainstorms.Heat waves occurred frequently and persisted for long durations.Summer and autumn drought occurred in central and eastern regions of the TGR.The autumn rains of West China occurred earlier this year,which brought much more rainfall than normal in central and western regions of the TGR.
基金supported by the National Key R&D Program of China [grant numbers 2017YFC1502402,2017YFD0300201 and2017YFA0605004]the funds of comprehensive monitoring of the Three Gorges Project,which was financed by the Ministry of Water Resources of China.
文摘This report provides a summary of the climate, as well as the major weather and climate events,over the Three Gorges Region of the Yangtze River(TGR) in 2018. The annual mean temperature over the TGR in 2018 was 0.2℃ above normal, and precipitation was near normal. Seasonal highlights included a second warmest spring in the 58-year period of records, with abundant rainfall, which resulted in the wettest March on record. Furthermore, this was the fourth-warmest summer on record in the TGR, which contributed a higher-than-normal number of hot days in2018. Precipitation was 17% and 30% less-than-normal in winter and summer, and 40% and 6% above average in spring and autumn, respectively. The annual mean wind speed in the TGR was higher than normal, and the annual mean relative humidity was near normal. The intensity of acid rain was relatively weak, being the second-weakest year since 1999. The major meteorological disaster types in the TGR include heat waves, drought, rainstorms and flooding, freezing rain, and snow. Heat waves occurred early in the summer and persisted for long durations with strong intensities. Long-term precipitation deficits resulted in drought conditions in summer 2018 across most regions of the TGR. Frequent heavy rainfall caused urban waterlogging. The early-year and late-year cold snaps were accompanied by heavy snowfall and rain over some locations across the TGR, which had adverse impacts on transportation, agriculture, electricity, and people’s lives.
基金supported by the National Key R&D Program of China[grant numbers 2017YFD0300201,2017YFA0605004,and 2017YFC1502402]funds of comprehensive monitoring of the Three Gorges Project,which was financed by the Ministry of Water Resources of China。
文摘In 2020,the average air temperature in the Three Gorges Region(TGR)of the Yangtze River basin was 17.2℃,which was close to normal,there were exceptionally fewer days than normal with high temperatures,and the high-temperature events mainly occurred in August.Meanwhile,the average precipitation was 1530.8 mm,which was a remarkable 29%more than usual,and the second-highest since 1961.The precipitation was obviously above-normal in summer,and the precipitation in both June and July was the second-highest of the same period in history.The average number of rainstorm days was higher than normal,and the second-highest since 1961.The average wind speed in the TGR was apparently higher than normal;the average relative humidity was slightly higher than normal;and there were no instances of acid rain,with the rain acidity showing a significant weakening trend over the previous 15 years.In the summer of 2020,the TGR experienced heavy rainstorms and flood disasters.Analysis shows that the frequent southward movement of cold air and abundant warm water vapor from the southwest were the direct causes of the abnormally high precipitation in the TGR from June to July.After the spring of 2020,the continuously high sea surface temperature in the Indian Ocean led to a continuously strong western Pacific subtropical high and its average location being situated more to the south than normal,which might have been an important cause for the abnormal climate conditions in the Yangtze River basin from June to July.
基金supported financially by the Public Project(20080219)of Ministry of Science and Technology in China
文摘Objective To define and evaluate the malaria transmission potential in the Yangtze River, following construction of the Three Gorges Reservoir. Methods Six villages, namely, Kaixian, Fengjie, Wanzhou, Fuling, Yubei, and Zigui were selected for investigating the malaria transmission potential in the reservoir. Transmission potential was estimated by mathematical modeling and evaluation of the local malaria situation. Factors that influenced the transmission potential were analyzed using Poisson regression analysis in combination with Grey Systematic Theory (based on evaluation by the Delphi method). Results Indirect fluorescent antibody data and the incidence of malaria in the local population were consistent with the malaria transmission potential calculated for the area. Multivariate Poisson regression analysis showed a statistically significant association between the riparian zone and the man‐biting rate. Conclusion The risk of a malaria epidemic can be forecasted using the malaria transmission potential parameters investigated here which was closely correlated with the riparian zone.
文摘Field investigation and laboratory work reveal that inhomogeneity of the deformation of the Xiannushan fault is mainly characterized by lateral zonation, longitudinal segmentation and downward stratification. Based on these results, a 3-D deformational structure model of the fault was established and its geometrical and kinematic characteristics in two main deformational stages i.e. the main Yanshanian and Himalayan were discussed. The directions of principal and the differential stresses in these two stages were determined by using conjugate joints, striations of fault planes and microstructures of the fault zone. The direction of σI is N-S in direction with differential stresses of 150-250 MPa in the Yanshanian, and N70E with a differential stress ranging from 80-120 MPa in the Himalayan.
基金financially supported by the National Natural Science Foundation of China (grants No.41072083 and 4157209)
文摘Objective In recent years, the birth time and evolution of the Three Gorges, Yangtze River has become a focused topic. Different from previous studies, this study used provenance analysis of Quaternary sediments to discuss this question. Among those minerals in Quaternary sediments, magnetite was rarely studied. This paper presents element geochemistry and backscatter images of detrital magnetites from the Quaternary sediments in the Yichang area of Hubei Province. By discussing the provenance changes of detratic magnetites, we suggested the birth time of the Three Gorges of the Yangtze River.
文摘This paper summarizes the factors affecting schistosomiasis transmission in the middle and lower reaches of the Yangtze River before and after the completion of the Three Gorges Dam and analyzes schistosomiasis prevalence trends to provide a basis for the application of the Three Gorges project methodologies in other areas.The Three Gorges Dam has demonstrated a positive effect on schistosomiasis control.Hubei,Hunan,Jiangxi,Anhui,and Jiangsu in the middle and lower reaches of the Yangtze River are currently regions with a high prevalence of schistosomiasis.These five provinces contained 97.62% of known snail areas and 93.66% of calculated schistosomiasis cases with 90.07% of counties (cities,districts) not yet meeting the criteria for schistosomiasis transmission interruption by the end of 2016.After the Three Gorges Dam was built,the prevalence of schistosomiasis in the middle and lower reaches of the Yangtze River decreased.By the end of 2016,the estimated number of cases decreased by 92.75% and the snail habitat areas decreased by 6.56% compared to 2004.No acute schistosomiasis cases have occurred for two consecutive years since 2015.
基金Thanks should be given to the National Natural Science Foundation of China grant 49772145 for the financial support of this study.
文摘On the basis of historical earthquake data and recent observations, two grey models prediction of the next seismic active period and the maximal magnitude of earthquakes which might occur during that period are constructed on the basis of the grey theory. As predicted by the two models, the next seismic active period would last 79 years, and that the maximal magnitude of earthquakes occurring within the period would not exceed 5.2. These results provide an important basis for the assessment of earthquake risks and reduction of disasters in the Three Gorges area.
基金This study was a contribution to Water conservancy Project 16-2-1 of the Seventh Five-Year Plan(1985-1989),entruated by the Surveying Bureau of rhe Committee of Water Resources of the Changjiang(Yangetze)River.
文摘A study has been made about the structural attribute of the NNW-trendingShizikou linear image belt in the head area of the reservoir of the Yangtze River Gorges and theevaluation of its crustal stability. On the basis of regional geological surveys and by making astructural analysis and a multidisciplinary study, it has been ascertained that the segment withthe best displayed image characteristics is marked by a gravity gliding structure with a multilay-er gliding fold type architecture. This paper also analyzes the medium conditions, slope struc-ture and dynamic setting for the formation of the structure system.
文摘The history of the Yangtze River is constituted by numerous river piracies that enabled the river to extend its drainage system. Two river captures are well recognized: the piracy of the Jinsha River (Jinshajiang) formerly tributary of the Red River at Shigu in Yunnan Province and the Three Gorges area that linked the upper and the middle Yangtze river reaches in Hubei province. The first one is well documented, while the second, because of difficulties to retrieve datable materials and the complexity of the area geomorphology, is still quite unknown. Numerous conflicting hypotheses have been formulated to explain the pattern of river piracy, no agreement exists on the location of the drainage divide and of the point of capture;chronologies extending from the Eocene to the late Quaternary are given. Geomorphic indices can be used to examine the geomorphological and tectonic processes responsible for the development of the drainage basins. In this paper, we analyzed drainage pattern, basin shape, basin asymmetry, stream junction angle to infer the drainage of the paleorivers that were pirated, and to propose a model of the pattern of river capture based on the importance of structure, tectonic and lithological controls in the area. We showed that the Three Gorges area has been very important to the history of the Yangtze river as the piracy of the upper and middle reaches enabled the river to reach its current extend.
文摘The giant perilous rock at Wangxia (named Wangxia perilous rock) is representative in Three Gorges of the Yangtze River, China, has threatened badly the navigation of the Yangtze River channel for a long period. The giant perilous rock is composed of siliceous limestone and argillaceous limestone, and includes two elements marking by W1 and W2, respectively. The W1 is an isolated pillar while the W2 is in clintheriform. The linking segment of dominant fissure in the W2 is composed by moniliform solution funnels at its back, and the locked segment of the dominant fissure at the base of the W2 is composed by two parts. For the locked part of the dominant fissure of the W2, the upper segment shows the same lithology with the perilous rock and it can be simplified as an elastic medium, for the lower segment composed by argillaceous shale and mudstone can be simplified as a strain-softening medium. Introducing the water-softened function, the constitutive curves with two kinds of medium materials for the locked segment in the dominant fissure of the W2 have been proposed. Based on energy principle, the cusp catastrophe model for perilous rock rupture is built and formulas for the transient elastic and impulsive acceleration and the elastic-impulsive velocity of perilous rock catastrophe rupture have been established. By the calculation, the elastic-impulsive acceleration for the catastrophe rupture of the W2 is 531.4 m/s2, while the average elastic-impulsive velocity is 2.608 m/s. Further, it is deduced that the elastic-impulsive velocity at the base of the W2 is about 5.2 m/s. For the transient ruture of the W2, there is a greater speed difference between the top and the base of the W2, which impels the giant perilous rock to be retroverted sliding rupture, coinciding with the fact. Undoubtedly, studies in this paper must play an important role to analyze the catastrophe rupture mechanism of giant perilous rocks at both banks in Three Gorges of the Yangtze River, China.
文摘The Yangtze River has nurtured the fertile land on both its banks and hundreds of millions of Chinese people. but its raging waters have also wreaked havoc on the people living in its reaches. Since the founding of New China, large-scale surveys, planning, scientific research and feasibility studies have been carried out in an effort to harness the
文摘The Three Gorges Project on the Yangtze River was started in December 1994. It is the largest water conservancy and hydropower project in the present world with a comprehensive result of flood prevention, generating and navigation. The reservoir can hold 22.2 billion cubic metres of water, thus being able to cut the flood flow of 27, 000 to 33, 000 cubic metres per second. Its hydropower station will have a total generating equipment capacity of 18.2 million kw with an annual generating quantity of 84.7 billion kwh to supply energy for the economic development of east China, central China and
文摘The region around the Three Gorges project on the Yangtze River has an area of 62552 square kilometres and population of 20.14 million. It limits a range hetween the sorth-north watersheds and from Yichang of Hubei Province to Jiangjin of Sichuan, including 24 cities and counties-Chongjing, Yichang and Wanxian etc. In this region, relief are mainly hills and middle-low mountains. Remote censing investigation and appraisal of land use and capacity which are two of the major restrict factors for the Three Gorges project have provided related scientific bases for macro-dicision-making of the project.
基金sponsored by the National Key Technology R&D Program (2008BAC38B04),China
文摘In accordance with the requirements of the National Key Technology R&D Program of the 11th "Five-year Plan", a densified seismic network consisting of 26 seismic stations was established at the Three Gorges Reservoir area in the section of Hubei Province in March 2009 (21 short-period seismographs, 5 broadband digital seismographs). From March to December, 2009, a total of 2,995 ML -0. 8 - 2. 9 earthquakes were detected during the trial impounding of the Three Gorges Reservoir ( water level rose from 145 m to 172.8m). Using the double difference earthquake location algorithm, 2,837 earthquakes were precisely re-located. The results show that the pattern of small local earthquake swarms in the Three Gorges Reservoir area took on a linear distribution or mass-like cluster distribution, the mass-like clusters of events were generally within a distance of 5 km from waterfront, and the linear distribution of the earthquakes could be extended to a distance of 16 km away from the waterfront. In the Hubei section of the Three Gorges Reservoir, earthquakes were mainly concentrated in the northern end of the Xiannvshan and Jiuwanxi faults near the Xiangxihe River, and along the banks of the Yangtze River at the west of Xietan township and the Shenlongxi area on the northern bank in the Badong region, with focal depths less than 10km, and 4km in average. Earthquake frequency in the reservoir region had a positive correlation with reservoir water level fluctuations, indicating that the seismicity belongs to reservoir induced earthquakes. Along the Shenlong River in the reservoir area, earthquakes showed three linear distributions in the northern Badong county, and distributed according to Karst distribution. There are underground rivers in the carbonate strata. When the reservoir was impounded, water permeated into the underground rivers, thus inducing earthquakes. Earthquakes in the areas on the crossriver segment of Xiannvshan fault, the Jiuwanxi fault and at the areas west of Xietan, Shazhen and Xizhen, may be related to the softening of discontinuities, such as the Nukou fault, the Xiannvshan fault, or the bedding joints, which would lead to failure of rock masses, thus, inducing earthquakes. However, convincing conclusions about the triggering mechanism still need further study. Additionally, near the areas south of Wenhua and Yanglin of Zigui county and at Rangkou town east of Badong county, mininginduced earthquakes occurred at the mines nearby, and on the shores of the reservoir are some collapse earthquakes.