Accurate information on the spatial distribution and temporal change of wetlands is vital to devise effective measures for their protection. This study uses satellite images in 1994 and 2001 to assess the effects of t...Accurate information on the spatial distribution and temporal change of wetlands is vital to devise effective measures for their protection. This study uses satellite images in 1994 and 2001 to assess the effects of topography and proximity to channels on wetland change in Maduo County on the Qinghai-Tibet Plateau, western China. In 1994 wetlands in the study area extended over 6,780.0 km2. They were distributed widely throughout the county, with a higher concentration in the south, and were especially prominent close to streams. The pattern of wetlands demonstrated a bell-shaped distribution curve with elevation, ranging over hill slopes with gradients from 0-19°, the commonest gradient being around 3°. Although the aspects of these hill slopes range over all directions, there is a lower concentration of wetlands facing east and southeast. The extent of wetlands in 2001 decreased to 6,181.1 km2. Marked spatial differentiation in the pattern of wetlands is evident, as their area increased by 1,193.3 km2 at lower elevations but decreased by 1,792.2 km2 at higher ground, resulting in a net decrease of 598.8 km2. In areas with a gradient <2° or >9° the area of wetlands remained approximately consistent from 1994-2001. Newly retained wetlands are situated in relatively flat lowland areas, with no evident preference in terms of aspect. Wetlands on north-, east- and northeast-facing hillslopes with a bearing of 1-86° were more prone to loss of area than other orientations. The altered pattern of wetland distribution from higher to lower elevation on north-facing slopes coincided with the doubling of annual temperature during the same period, suggesting that climate warming could be an important cause.展开更多
The world today is .faced with the critical challenge of developing industries .for both high technological efficiency and possibly less impact on resources and the environment. This paper employs the Slacks-based mea...The world today is .faced with the critical challenge of developing industries .for both high technological efficiency and possibly less impact on resources and the environment. This paper employs the Slacks-based measure （SBM） to conduct an empirical analysis of China＇s industrial environmental efficiency between 1998 and 2008. We.found a slight decline in SBM nationwide due to the combined effects of resource^environmental constraint as well as technological progress. From a static perspective, there is a clear disparity in coordination among regions, particularly between western regions and eastern coastal regions. From a dynamic perspective, there is limited change in the coordination of industries with natural resources and the environment in coastal and central regions, but a marked decline in the northeast and western regions. This contrast can be traced to the .following reasons： the capital-intensive structure of the economy and the high proportion of large industrial enterprises that restrict the improvement of SBM environmental efficiency. Higher living standards, indigenous innovation, acquisition of new technologies, and foreign direct investment will be conducive to industries＇synchronous development with natural resources and the environment.展开更多
The crustal structure of the northwestern sub-basin area of the South China Sea was modeled by inverting a wide-angle seismic survey line across the entire region and on both sides of its bounding continental margins....The crustal structure of the northwestern sub-basin area of the South China Sea was modeled by inverting a wide-angle seismic survey line across the entire region and on both sides of its bounding continental margins. The survey line extended over 484 km. A total of 14 Ocean Bottom Seismometers (OBS) were deployed at intervals of 30 km to record air-gun array sources with a combined volume of 5160 in 3 . The crustal velocity structure of the northwestern sub-basin area was acquired through the integration of multi-channel seismic data. OBS data were processed and modeled initially using ray tracing inversion techniques. Results indicate that crustal thickness under the continental slope decreases from 21 to 11 km, crustal thickness of the northwestern sub-basin is 7.7 km, and the depth to the Moho ascends from 21 km under the upper continental slope to 11 km under the middle basin. The crust of the northwestern sub-basin is similar to that of the eastern sub-basin in its oceanic crustal structure. This structure has a thicker layer 1 (sedimentary layer) and a thinner layer 2. These characteristics are especially clear in the eastern sub-basin, which differs somewhat from typical oceanic crust. The tectonic geometry and velocity structure of the northwestern sub-basin and its margins comprise a symmetrical conjugate and indicate a pure shear mode with regard to the continental margin rifting mechanism. We did not find clear seismic signals from high velocity layers under the lower crust of the continental margin in the northern part of the northwestern sub-basin, which provides new evidence for the idea that the western part of the northern continental margin of the South China Sea constitutes nonvolcanic crust. Because the seafloor spreading period of the northwestern sub-basin was short, layer 2 might have experienced asymmetrical basalt magma flows, which may have blurred the magnetic anomaly lineations of the northwestern sub-basin.展开更多
Coordinated regional development has long been a focus of the Chinese Government.For instance,over the past few decades,the government has rolled out the western region development plan as well as its strategy of revi...Coordinated regional development has long been a focus of the Chinese Government.For instance,over the past few decades,the government has rolled out the western region development plan as well as its strategy of revitalizing northeast China.It has also developed economic zones in regions such as the west coast of the Taiwan Straits and the Yangtze River Delta.At present,another such regional development zone,展开更多
基金supported by the International Science & Technology Cooperation Program of China (Grant No. 2011DFG93160,2011DFA20820)the National Natural Sciences Foundation of China (Grant No.41161084)the Scientific Research Collaboration and Training of Top Scientists project (Document No. 2009-1599),Department of International Exchange & Cooperation of the Chinese Ministry of Education
文摘Accurate information on the spatial distribution and temporal change of wetlands is vital to devise effective measures for their protection. This study uses satellite images in 1994 and 2001 to assess the effects of topography and proximity to channels on wetland change in Maduo County on the Qinghai-Tibet Plateau, western China. In 1994 wetlands in the study area extended over 6,780.0 km2. They were distributed widely throughout the county, with a higher concentration in the south, and were especially prominent close to streams. The pattern of wetlands demonstrated a bell-shaped distribution curve with elevation, ranging over hill slopes with gradients from 0-19°, the commonest gradient being around 3°. Although the aspects of these hill slopes range over all directions, there is a lower concentration of wetlands facing east and southeast. The extent of wetlands in 2001 decreased to 6,181.1 km2. Marked spatial differentiation in the pattern of wetlands is evident, as their area increased by 1,193.3 km2 at lower elevations but decreased by 1,792.2 km2 at higher ground, resulting in a net decrease of 598.8 km2. In areas with a gradient <2° or >9° the area of wetlands remained approximately consistent from 1994-2001. Newly retained wetlands are situated in relatively flat lowland areas, with no evident preference in terms of aspect. Wetlands on north-, east- and northeast-facing hillslopes with a bearing of 1-86° were more prone to loss of area than other orientations. The altered pattern of wetland distribution from higher to lower elevation on north-facing slopes coincided with the doubling of annual temperature during the same period, suggesting that climate warming could be an important cause.
文摘The world today is .faced with the critical challenge of developing industries .for both high technological efficiency and possibly less impact on resources and the environment. This paper employs the Slacks-based measure （SBM） to conduct an empirical analysis of China＇s industrial environmental efficiency between 1998 and 2008. We.found a slight decline in SBM nationwide due to the combined effects of resource^environmental constraint as well as technological progress. From a static perspective, there is a clear disparity in coordination among regions, particularly between western regions and eastern coastal regions. From a dynamic perspective, there is limited change in the coordination of industries with natural resources and the environment in coastal and central regions, but a marked decline in the northeast and western regions. This contrast can be traced to the .following reasons： the capital-intensive structure of the economy and the high proportion of large industrial enterprises that restrict the improvement of SBM environmental efficiency. Higher living standards, indigenous innovation, acquisition of new technologies, and foreign direct investment will be conducive to industries＇synchronous development with natural resources and the environment.
基金supported by National Basic Research Program of China (Grant No. 2007CB411701)National Natural Science Foundation of China (Grant Nos. 40876035 and 91028006)Scientific Research Fund of the Second Institute of Oceanography, State Oceanic Administration (Grant No. JG200803)
文摘The crustal structure of the northwestern sub-basin area of the South China Sea was modeled by inverting a wide-angle seismic survey line across the entire region and on both sides of its bounding continental margins. The survey line extended over 484 km. A total of 14 Ocean Bottom Seismometers (OBS) were deployed at intervals of 30 km to record air-gun array sources with a combined volume of 5160 in 3 . The crustal velocity structure of the northwestern sub-basin area was acquired through the integration of multi-channel seismic data. OBS data were processed and modeled initially using ray tracing inversion techniques. Results indicate that crustal thickness under the continental slope decreases from 21 to 11 km, crustal thickness of the northwestern sub-basin is 7.7 km, and the depth to the Moho ascends from 21 km under the upper continental slope to 11 km under the middle basin. The crust of the northwestern sub-basin is similar to that of the eastern sub-basin in its oceanic crustal structure. This structure has a thicker layer 1 (sedimentary layer) and a thinner layer 2. These characteristics are especially clear in the eastern sub-basin, which differs somewhat from typical oceanic crust. The tectonic geometry and velocity structure of the northwestern sub-basin and its margins comprise a symmetrical conjugate and indicate a pure shear mode with regard to the continental margin rifting mechanism. We did not find clear seismic signals from high velocity layers under the lower crust of the continental margin in the northern part of the northwestern sub-basin, which provides new evidence for the idea that the western part of the northern continental margin of the South China Sea constitutes nonvolcanic crust. Because the seafloor spreading period of the northwestern sub-basin was short, layer 2 might have experienced asymmetrical basalt magma flows, which may have blurred the magnetic anomaly lineations of the northwestern sub-basin.
文摘Coordinated regional development has long been a focus of the Chinese Government.For instance,over the past few decades,the government has rolled out the western region development plan as well as its strategy of revitalizing northeast China.It has also developed economic zones in regions such as the west coast of the Taiwan Straits and the Yangtze River Delta.At present,another such regional development zone,
