Hyperspectral data are an important source for monitoring soil salt content on a large scale. However, in previous studies, barriers such as interference due to the presence of vegetation restricted the precision of m...Hyperspectral data are an important source for monitoring soil salt content on a large scale. However, in previous studies, barriers such as interference due to the presence of vegetation restricted the precision of mapping soil salt content. This study tested a new method for predicting soil salt content with improved precision by using Chinese hyperspectral data, Huan Jing-Hyper Spectral Imager(HJ-HSI), in the coastal area of Rudong County, Eastern China. The vegetation-covered area and coastal bare flat area were distinguished by using the normalized differential vegetation index at the band length of 705 nm(NDVI705). The soil salt content of each area was predicted by various algorithms. A Normal Soil Salt Content Response Index(NSSRI) was constructed from continuum-removed reflectance(CR-reflectance) at wavelengths of 908.95 nm and 687.41 nm to predict the soil salt content in the coastal bare flat area(NDVI705 < 0.2). The soil adjusted salinity index(SAVI) was applied to predict the soil salt content in the vegetation-covered area(NDVI705 ≥ 0.2). The results demonstrate that 1) the new method significantly improves the accuracy of soil salt content mapping(R2 = 0.6396, RMSE = 0.3591), and 2) HJ-HSI data can be used to map soil salt content precisely and are suitable for monitoring soil salt content on a large scale.展开更多
The statistics of tidal gauging records showed that the mean sea level of the China Seas has risen for 14 cm in past 100 years. The annual mean sea levels of the Eastern China Seas have been rising at a speed of about...The statistics of tidal gauging records showed that the mean sea level of the China Seas has risen for 14 cm in past 100 years. The annual mean sea levels of the Eastern China Seas have been rising at a speed of about 0.21 -0.23 cm/a since 1960. The annual mean sea levels of the Eastern China Seas in 1989 were 1.45 cm higher than that in 1988 on average.The sea level rise may cause the damage of the dynamical balance of the natural environments in the coastal area? and form or strengthen many coastal disasters, such as storm-tide catastrophic events, sea water invasion landward, soil salinization in coastal lowland and plains, and beach erosion retreat.展开更多
The aim of this study is to evaluate the current state of rural area development at the county level in the eastern coastal China. An evaluation index system including 18 factors was developed, and a rural development...The aim of this study is to evaluate the current state of rural area development at the county level in the eastern coastal China. An evaluation index system including 18 factors was developed, and a rural development index (RDI) was constructed to evaluate rural development state in 2000, 2004, and 2008. The quantitative evaluation indicated the following results. 1) This study derived four dominating components by means of principal component analysis, which can explain 78.2% of the total information, namely agricultural production input, the basic condition of agriculture, the comparative effectiveness of grain production, and the household′s own basic conditions. 2) Since the turn of the new millennium, the rural area in the eastern coastal China has experienced a rapid development in general. Well developed, developed, moderately developed and undeveloped rural areas respectively occupied 29.32%, 22.33%, 21.91%, and 10.51% in 2008. 3) The countryside had maintained a sound momentum of developing trend between 2000 and 2008, while the rural development in the eastern coastal China lacked sustainability. And 4) industrialization, urbanization, original economic basis, and location are four major driving forces of the disparity of rural area development in the eastern coastal China. Given these results, the strategies and policies for the improvement of each rural group were put forward.展开更多
Eastern and southern coastal zones of Laizhou Bay are the most representative seawater intruded areas in the world, with two intrusion sources of contemporary seawater and paleobrine. In order to reveal the complicate...Eastern and southern coastal zones of Laizhou Bay are the most representative seawater intruded areas in the world, with two intrusion sources of contemporary seawater and paleobrine. In order to reveal the complicated hydrochemical changing process and the mechanism of fresh groundwater being polluted by saltwater, we conducted long-term observation and hydrochemical analysis at four observing sections of typical salt-fresh water transitional zone. The study indicates that seawater and brine intrusion processes have different hydrochemical features, and that ion exchange and adsorption actions between water and aquifer produce great influence on the intrusion.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41230751,41101547)Scientific Research Foundation of Graduate School of Nanjing University(No.2012CL14)
文摘Hyperspectral data are an important source for monitoring soil salt content on a large scale. However, in previous studies, barriers such as interference due to the presence of vegetation restricted the precision of mapping soil salt content. This study tested a new method for predicting soil salt content with improved precision by using Chinese hyperspectral data, Huan Jing-Hyper Spectral Imager(HJ-HSI), in the coastal area of Rudong County, Eastern China. The vegetation-covered area and coastal bare flat area were distinguished by using the normalized differential vegetation index at the band length of 705 nm(NDVI705). The soil salt content of each area was predicted by various algorithms. A Normal Soil Salt Content Response Index(NSSRI) was constructed from continuum-removed reflectance(CR-reflectance) at wavelengths of 908.95 nm and 687.41 nm to predict the soil salt content in the coastal bare flat area(NDVI705 < 0.2). The soil adjusted salinity index(SAVI) was applied to predict the soil salt content in the vegetation-covered area(NDVI705 ≥ 0.2). The results demonstrate that 1) the new method significantly improves the accuracy of soil salt content mapping(R2 = 0.6396, RMSE = 0.3591), and 2) HJ-HSI data can be used to map soil salt content precisely and are suitable for monitoring soil salt content on a large scale.
文摘The statistics of tidal gauging records showed that the mean sea level of the China Seas has risen for 14 cm in past 100 years. The annual mean sea levels of the Eastern China Seas have been rising at a speed of about 0.21 -0.23 cm/a since 1960. The annual mean sea levels of the Eastern China Seas in 1989 were 1.45 cm higher than that in 1988 on average.The sea level rise may cause the damage of the dynamical balance of the natural environments in the coastal area? and form or strengthen many coastal disasters, such as storm-tide catastrophic events, sea water invasion landward, soil salinization in coastal lowland and plains, and beach erosion retreat.
基金Under the auspices of National Natural Science Foundation of China (No. 41130748,40635029)Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-EW-304)
文摘The aim of this study is to evaluate the current state of rural area development at the county level in the eastern coastal China. An evaluation index system including 18 factors was developed, and a rural development index (RDI) was constructed to evaluate rural development state in 2000, 2004, and 2008. The quantitative evaluation indicated the following results. 1) This study derived four dominating components by means of principal component analysis, which can explain 78.2% of the total information, namely agricultural production input, the basic condition of agriculture, the comparative effectiveness of grain production, and the household′s own basic conditions. 2) Since the turn of the new millennium, the rural area in the eastern coastal China has experienced a rapid development in general. Well developed, developed, moderately developed and undeveloped rural areas respectively occupied 29.32%, 22.33%, 21.91%, and 10.51% in 2008. 3) The countryside had maintained a sound momentum of developing trend between 2000 and 2008, while the rural development in the eastern coastal China lacked sustainability. And 4) industrialization, urbanization, original economic basis, and location are four major driving forces of the disparity of rural area development in the eastern coastal China. Given these results, the strategies and policies for the improvement of each rural group were put forward.
基金National Natural Science Foundation of China, No.49871011.
文摘Eastern and southern coastal zones of Laizhou Bay are the most representative seawater intruded areas in the world, with two intrusion sources of contemporary seawater and paleobrine. In order to reveal the complicated hydrochemical changing process and the mechanism of fresh groundwater being polluted by saltwater, we conducted long-term observation and hydrochemical analysis at four observing sections of typical salt-fresh water transitional zone. The study indicates that seawater and brine intrusion processes have different hydrochemical features, and that ion exchange and adsorption actions between water and aquifer produce great influence on the intrusion.
