The basic strategies in establishing the Chinese geodetic coordinate system 2000 have been summarized, including the definition of the coordinate system, the structure of the terrestrial reference frame, the functiona...The basic strategies in establishing the Chinese geodetic coordinate system 2000 have been summarized, including the definition of the coordinate system, the structure of the terrestrial reference frame, the functional and stochastic models involved in the realization of the reference frame as well as the improvements of the adjustment procedures. First, the fundamental frame of the coordinate system is composed of the permanent GPS tracking network in China which is integrated into the international GPS service stations by combined adjustment, in order to guarantee the consistence between the international terrestrial reference system and the Chinese geodetic coordinate system. Second, the extended frame of the coordinate system is composed of the unified 2000' national GPS network which is integrated by 6 nationwide GPS networks with more than 2500 stations under the controlling of the fundamental frame. Third, the densified frame is composed of national astronomical geodetic network with nearly 50 thousand stations which was updated by the combined adjustment with the 2000' national GPS network, thus the datum of the national astronomical geodetic network has been unified and the precision greatly improved. By the optimal data fusion method the influences of the datum errors, systematic errors and the outliers in the separated geodetic networks are weakened in the unified Chinese geodetic coordinate frame. The significance in application of the new geodetic coordinate system and the existing problems in the reference frame are described and analyzed.展开更多
Territorial water is a significant part of national sovereignty of China,thus the infrastructures of national space datum and location services should cover the sea areas except for the land areas.China has establishe...Territorial water is a significant part of national sovereignty of China,thus the infrastructures of national space datum and location services should cover the sea areas except for the land areas.China has established relatively complete geodetic coordinate frame in land areas over the past decades,including the lastest developed China Geodetic Coordinate System 2000(CGCS 2000)with its reference frame and the national gravity datum 2000.However,the currently used geodetic infrastructures have not well covered the sea areas of China.The marine geodetic datum and marine navigation technologies need to be further developed and extended to satisfy the national demands of marine environment and resources detection,scientific investigation as well as marine economy development in new era of China.This paper mainly reviews the development and the progress of Chinese marine geodetic datum and marine navigation,analyses related key technologies in establishing our national marine geodetic datum.Some current trends and future directions for independently developing our national marine geodetic datum and marine navigation technologies are discussed.展开更多
Sea level rise （SLR） is a major projected threat of climate change that is expected to affect developing coastal cities located in estuarine delta regions, Shanghai is one such city, being located in the Yangtze Riv...Sea level rise （SLR） is a major projected threat of climate change that is expected to affect developing coastal cities located in estuarine delta regions, Shanghai is one such city, being located in the Yangtze River Delta （YRD）, It is difficult, however, for decision-makers to implement adaptation due to the uncer- tain causes, magnitudes, and timings of SLR behaviors, This paper attempts to map the causes and mag- nitudes of SLR behaviors on a decadal scale, We analyze the tidal level records from 11 tidal gauge stations and the corresponding bathymetry measurements around these stations since 1921, We identify three new SLR behaviors along the Shanghai coast due to anthropogenic geomorphologic changes （AGCs）, besides the well-known eustatic sea level rise （ESLR）, tectonic subsidence （TS）, and urban land subsidence （ULS）, The first new behavior is regional sea level rise （RSLR）, which occurs as a result of land reclamation and deep waterway regulation, The second is regional sea level fall （RSLF）, which occurs because the channel bed is eroded due to sediment supply decline in the river catchment, The last SLR behavior is local tidal datum rise （LTDR）. Thus, we project that the magnitude of SLR for the Shanghai coast ranges from 10 cm to 16 cm from 2011 to 2030, Clarifying SLR behaviors is important to aid local decision- makers in planning structural and non-structural measures to combat escalating flood damage costs in an estuarine delta system; this field is full of future challenges,展开更多
基金Supported partly by National Natural Science Foundations of China (Grant Nos. 40774001 and 40841021)the National High-Tech Research & Development Program of China (Grant No. 2007AA12Z331)
文摘The basic strategies in establishing the Chinese geodetic coordinate system 2000 have been summarized, including the definition of the coordinate system, the structure of the terrestrial reference frame, the functional and stochastic models involved in the realization of the reference frame as well as the improvements of the adjustment procedures. First, the fundamental frame of the coordinate system is composed of the permanent GPS tracking network in China which is integrated into the international GPS service stations by combined adjustment, in order to guarantee the consistence between the international terrestrial reference system and the Chinese geodetic coordinate system. Second, the extended frame of the coordinate system is composed of the unified 2000' national GPS network which is integrated by 6 nationwide GPS networks with more than 2500 stations under the controlling of the fundamental frame. Third, the densified frame is composed of national astronomical geodetic network with nearly 50 thousand stations which was updated by the combined adjustment with the 2000' national GPS network, thus the datum of the national astronomical geodetic network has been unified and the precision greatly improved. By the optimal data fusion method the influences of the datum errors, systematic errors and the outliers in the separated geodetic networks are weakened in the unified Chinese geodetic coordinate frame. The significance in application of the new geodetic coordinate system and the existing problems in the reference frame are described and analyzed.
文摘Territorial water is a significant part of national sovereignty of China,thus the infrastructures of national space datum and location services should cover the sea areas except for the land areas.China has established relatively complete geodetic coordinate frame in land areas over the past decades,including the lastest developed China Geodetic Coordinate System 2000(CGCS 2000)with its reference frame and the national gravity datum 2000.However,the currently used geodetic infrastructures have not well covered the sea areas of China.The marine geodetic datum and marine navigation technologies need to be further developed and extended to satisfy the national demands of marine environment and resources detection,scientific investigation as well as marine economy development in new era of China.This paper mainly reviews the development and the progress of Chinese marine geodetic datum and marine navigation,analyses related key technologies in establishing our national marine geodetic datum.Some current trends and future directions for independently developing our national marine geodetic datum and marine navigation technologies are discussed.
基金This study was financially supported by the National Natural Science Foundation of China-the Netherlands Organization for Scientific Research-Research Councils UK （NSFC-NWO-RCUK） （51761135023）, the Shanghai Science and Technology Committee （10dz1210600）, the National Sea Welfare Project （201005019- 09）, the National Natural Science Foundation of China （41476075）, and the China Geological Survey （DD20160246）. We would like to give a special acknowledgement to the second author, ProfessorJi-Yu Chen, who was a great scientist of estuarine and coastal research, for the excellent suggestions and guidelines he provided over a considerable period of time before he passed away.
文摘Sea level rise （SLR） is a major projected threat of climate change that is expected to affect developing coastal cities located in estuarine delta regions, Shanghai is one such city, being located in the Yangtze River Delta （YRD）, It is difficult, however, for decision-makers to implement adaptation due to the uncer- tain causes, magnitudes, and timings of SLR behaviors, This paper attempts to map the causes and mag- nitudes of SLR behaviors on a decadal scale, We analyze the tidal level records from 11 tidal gauge stations and the corresponding bathymetry measurements around these stations since 1921, We identify three new SLR behaviors along the Shanghai coast due to anthropogenic geomorphologic changes （AGCs）, besides the well-known eustatic sea level rise （ESLR）, tectonic subsidence （TS）, and urban land subsidence （ULS）, The first new behavior is regional sea level rise （RSLR）, which occurs as a result of land reclamation and deep waterway regulation, The second is regional sea level fall （RSLF）, which occurs because the channel bed is eroded due to sediment supply decline in the river catchment, The last SLR behavior is local tidal datum rise （LTDR）. Thus, we project that the magnitude of SLR for the Shanghai coast ranges from 10 cm to 16 cm from 2011 to 2030, Clarifying SLR behaviors is important to aid local decision- makers in planning structural and non-structural measures to combat escalating flood damage costs in an estuarine delta system; this field is full of future challenges,
