Anchovies are migratory fish and adult individuals migrate in group from the sea into the river every year because of reproductive needs. TheYangtze River is the largest river in China, with rich food and fish species...Anchovies are migratory fish and adult individuals migrate in group from the sea into the river every year because of reproductive needs. TheYangtze River is the largest river in China, with rich food and fish species, hence, the Yangtze River would be an ideal habitat for growth and reproduction of anchovy. In this pa- per, based on fishing log data of anchovy in Jiangsu section of the Yangtze River, realted analysis was conducted in digital map using statistical software and GIS. From 2008 to 2011, the number of anchovy fishing vessels and fishing days in Jiangsu section remained stable, but the fishing volume and economic profit of single-vessel fluctuated constantly. This study provides references and advices for plan and management of anchovy fishery resource to administrative department.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
In this paper, we use the conductivity-temperature-depth (CTD) observation data and a three-dimensional ocean model in a seasonally-varying forcing field to study the barrier layer (BL) in the PN section in the East C...In this paper, we use the conductivity-temperature-depth (CTD) observation data and a three-dimensional ocean model in a seasonally-varying forcing field to study the barrier layer (BL) in the PN section in the East China Sea (ECS). The BL can be found along the PN section with obviously seasonal variability. In winter, spring and autumn, the BL occurs around the slope where the cold shelf water meets with the warm Kuroshio water. In summer, the BL can also be found in the shelf area near salinity front of the Changjiang (Yangtze) River Dilution Water (YRDW). Seasonal variations of BL in the PN section are caused by local hydrological characteristics and seasonal variations of atmospheric forcing. Strong vertical convection caused by sea surface cooling thickens the BL in winter and spring in the slope area. Due to the large discharge of Changjiang River in summer, the BL occurs extensively in the shelf region where the fresh YRDW and the salty bottom water meet and form a strong halocline above the seasonal thermocline. The formation mechanism of BL in the PN section can be explained by the vertical shear of different water masses, which is called the advection mechanism. The interannual variation of BL in summer is greatly affected by the YRDW. In the larger YRDW year (such as 1998), a shallow but much thicker BL existed on the shelf area.展开更多
The waterway in the middle and lower reaches of the Yangtze River has long been known as the Golden Waterway and has served as an important link in the construction of the Yangtze River Economic Belt.Therefore,expandi...The waterway in the middle and lower reaches of the Yangtze River has long been known as the Golden Waterway and has served as an important link in the construction of the Yangtze River Economic Belt.Therefore,expanding its dimensions is a significant goal,particularly given the long-range cumulative erosion occurring downstream of the Three Gorges Dam (TGD),which has been concentrated in the dry river channel.With the regulation of the volume from upstream reservoirs and the TGD,the minimum discharge and water level of the river downstream are increasing,and creating favorable conditions for the increase of the depth of the waterway.The discharge compensation effect during the dry season offsets the decline in the water level of the river channel caused by the down-cutting of part of the riverbed,but the minimum navigable water level of the segment near the dam still shows a declining trend.In recent years,several waterway remediation projects have been implemented in the downstream reaches of the TGD and although the waterway depth and width have been increased,the channel dimensions are still insufficient in the Yichang-Anqing reach (with a total length of 1026 km),as compared to the upstream reservoir area and the deep water channel in the downstream tidal reaches.A comprehensive analysis of the water depth and the number and length of shoals in the waterway indicates that its dimensions can be increased to 4.5 m ×200 m and 6.0 m×200 m in the Yichang-Wuhan and Wuhan-Anqing reaches,respectively.This is also feasible given the remediation technologies currently available,but remediation projects need to be coordinated with those for flood prevention and ecological protection.展开更多
基金Supported by the R&D Special Fund for Public Welfare Industry(201203086)Special Financial Fund of Ministry of Agriculture(6125005)Central Public-interest Scientific Institution Basal Research Fund(2011JBFC04)~~
文摘Anchovies are migratory fish and adult individuals migrate in group from the sea into the river every year because of reproductive needs. TheYangtze River is the largest river in China, with rich food and fish species, hence, the Yangtze River would be an ideal habitat for growth and reproduction of anchovy. In this pa- per, based on fishing log data of anchovy in Jiangsu section of the Yangtze River, realted analysis was conducted in digital map using statistical software and GIS. From 2008 to 2011, the number of anchovy fishing vessels and fishing days in Jiangsu section remained stable, but the fishing volume and economic profit of single-vessel fluctuated constantly. This study provides references and advices for plan and management of anchovy fishery resource to administrative department.
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.
基金Supported by National Basic Research Program of China (973 Program, No. 2005CB422303 and 2007CB411804)the Key Project of the International Science and Technology Cooperation Program of China (No. 2006DFB21250)+1 种基金the "111 Project" of the Ministry of Education (No. B07036)the Program for New Century Excellent Talents in University, China (No. NECT-07-0781)
文摘In this paper, we use the conductivity-temperature-depth (CTD) observation data and a three-dimensional ocean model in a seasonally-varying forcing field to study the barrier layer (BL) in the PN section in the East China Sea (ECS). The BL can be found along the PN section with obviously seasonal variability. In winter, spring and autumn, the BL occurs around the slope where the cold shelf water meets with the warm Kuroshio water. In summer, the BL can also be found in the shelf area near salinity front of the Changjiang (Yangtze) River Dilution Water (YRDW). Seasonal variations of BL in the PN section are caused by local hydrological characteristics and seasonal variations of atmospheric forcing. Strong vertical convection caused by sea surface cooling thickens the BL in winter and spring in the slope area. Due to the large discharge of Changjiang River in summer, the BL occurs extensively in the shelf region where the fresh YRDW and the salty bottom water meet and form a strong halocline above the seasonal thermocline. The formation mechanism of BL in the PN section can be explained by the vertical shear of different water masses, which is called the advection mechanism. The interannual variation of BL in summer is greatly affected by the YRDW. In the larger YRDW year (such as 1998), a shallow but much thicker BL existed on the shelf area.
基金supported by the National Key Research and Development Program of China(Grants No.2016YFC0402306 and 2016YFC0402106)the National Natural Science Foundation of China(Grant No.51809131)+1 种基金the Key Laboratory of Yellow River Sediment Research,Ministry of Water Resources of China(Grant No.2016002)the Fundamental Research Funds for Central Public Welfare Research Institutes(Grants No.TKS160103,TKS180201,and TKS180411)
文摘The waterway in the middle and lower reaches of the Yangtze River has long been known as the Golden Waterway and has served as an important link in the construction of the Yangtze River Economic Belt.Therefore,expanding its dimensions is a significant goal,particularly given the long-range cumulative erosion occurring downstream of the Three Gorges Dam (TGD),which has been concentrated in the dry river channel.With the regulation of the volume from upstream reservoirs and the TGD,the minimum discharge and water level of the river downstream are increasing,and creating favorable conditions for the increase of the depth of the waterway.The discharge compensation effect during the dry season offsets the decline in the water level of the river channel caused by the down-cutting of part of the riverbed,but the minimum navigable water level of the segment near the dam still shows a declining trend.In recent years,several waterway remediation projects have been implemented in the downstream reaches of the TGD and although the waterway depth and width have been increased,the channel dimensions are still insufficient in the Yichang-Anqing reach (with a total length of 1026 km),as compared to the upstream reservoir area and the deep water channel in the downstream tidal reaches.A comprehensive analysis of the water depth and the number and length of shoals in the waterway indicates that its dimensions can be increased to 4.5 m ×200 m and 6.0 m×200 m in the Yichang-Wuhan and Wuhan-Anqing reaches,respectively.This is also feasible given the remediation technologies currently available,but remediation projects need to be coordinated with those for flood prevention and ecological protection.
