The relationship between heat content and the interannual time scale is examined with satellite sea surface height （SSH） in the global ocean on altimeter measurements, historical hydrography, and model assimilation ...The relationship between heat content and the interannual time scale is examined with satellite sea surface height （SSH） in the global ocean on altimeter measurements, historical hydrography, and model assimilation outputs. Results show that correlation between altimetric SSH and heat content in the upper 700 m calculated from Ishii data is geographically nonuniform. In the tropical ocean, heat content and SSH are strongly correlated and exhibit nearly the same interannual variations. In the polar ocean, their correlation is relatively weak. Further analysis with Simple Ocean Data Assimilation outputs shows that such nonuniform distribution is not from dynamical origin but from the limited integral depth selected to calculate heat content. The integral depth of 700 m is inadequate to capture variation of the deep main thermocline in the polar region. The halosteric effect also contributes to the nonuniform pattern of correlation, because saline contraction becomes significant in the polar ocean owing to low temperature.展开更多
This paper compares the differences between the mathematical model in graph theory and GIS network analysis model. Thus it claims that the GIS network analysis model needs to solve. Then this paper introduces the spat...This paper compares the differences between the mathematical model in graph theory and GIS network analysis model. Thus it claims that the GIS network analysis model needs to solve. Then this paper introduces the spatial data management methods in object\|relation database for GIS and discusses its effects on the network analysis model. Finally it puts forward the GIS network analysis model based on the object\|relation database. The structure of the model is introduced in detail and research is done to the internal and external memory data structure of the model. The results show that it performs well in practice.展开更多
The map of reflecting horizon A, plotted on the basis of regional geophysical materials, yieldsinformation about the bottom topography of sedimentary cover of the West-Siberian Basin within Nadym-Taz interfluve. Throu...The map of reflecting horizon A, plotted on the basis of regional geophysical materials, yieldsinformation about the bottom topography of sedimentary cover of the West-Siberian Basin within Nadym-Taz interfluve. Through morphotectonic analysis about this surface, the authors are able tounderstand the distribution characteristics of the main topographic irregularities, with the blockstructure of the lower cover floors and underlying complexes as the focus.The largest irregularities are caused by the presence of three regional altitude steps, which show a regional tendency of basement being submerged in the north-north-east direction. Within these irregularities, the authors have distinguished some regions, which can be divided, based on the characteristics of morphostructural distribution, into two groups, i.e., areal (Nadym, Tol'ka, Urengoy)and belt (Tarko-Sale, Russko-Chasel'ka and Messoyakha). The first ones represent quasihomogeneous blocks, whose surfaces are complicated by irregular low-amplitude elevations and troughs and low-gradient zones with gradient values being up to 0.03, or they submerge stepwise, with the leveled areas being separated by zones with high gradients (0.07-0.15). The morphostructure of the other group of regions is characterized by the en-echelon distribution of contrastingly positive and negative elements with high values of slope gradients (higher than 0.1-0.2).展开更多
Human economic and social needs can be in conflict with ecosystem needs. Land development increases impervious surfaces causing significant negative impacts to aquatic ecosystems. Many impervious surface estimates are...Human economic and social needs can be in conflict with ecosystem needs. Land development increases impervious surfaces causing significant negative impacts to aquatic ecosystems. Many impervious surface estimates are derived from remote sensing data, developed by using different methods and often out of date. Remote sensing data is often at scales applicable to regional management, but not local planning decisions. To date, no standardized annual dataset of percent impervious surface exists for use at both local and watershed scales. Effective communication between natural resource managers and local planners has been lacking. One solution is to monitor percent impervious surface with a relative index rather than direct measure. A relative index model can use a currency, like foundation square feet per hectare, which is useful for all decision makers. One data source for developing a relative index of impervious surface is property tax data. These data document annual land development at local scale. Here, the author presents the use of Maryland property tax data to index land development and percent impervious surface.展开更多
The distribution characteristics of the impact craters can provide a large amount of information on impact history and the lunar evolution process. In this research, based on the digital elevation model （DEM） data o...The distribution characteristics of the impact craters can provide a large amount of information on impact history and the lunar evolution process. In this research, based on the digital elevation model （DEM） data originating from Change＇E-1 CCD stereo camera, three automatic extraction methods for the impact craters are implemented in two research areas： direct extraction from flooded DEM data （the Flooded method）, object-oriented extraction from DEM data by using ENVI ZOOM function （the Object-Oriented method） and novel object-oriented extraction from flooded DEM data （the Flooded Object-Oriented method）. Accuracy assessment, extracted degree computation, cumulative frequency analysis, shape and age analysis of the extracted craters combined display the following results. （1） The Flooded Object-Oriented method yields better accuracy than the other two methods in the two research areas; the extraction result of the Flooded method offers the similar accuracy to that of the Object-Oriented method. （2） The cumulative frequency curves for the extracted craters and the confirmed craters share a simi- lar change trajectory. （3） The number of the impact craters extracted by the three methods in the Imbrian period is the largest and is of various types; as to their age earlier than lmbrain, it is difficult to extract because they could have been destroyed.展开更多
Up to now, many lunar explorations concluded their scientific mission through the impact on the lunar surface. The prediction and positioning of impact sites are based on the extrapolated orbiting data together with t...Up to now, many lunar explorations concluded their scientific mission through the impact on the lunar surface. The prediction and positioning of impact sites are based on the extrapolated orbiting data together with the real time orbiting data and observations from ground based telescope provided by TT ＆ C System. As most lunar missions carded cameras onboard, a new method of positioning of CE-1 impact site is put forward. It is based on the CCD image data photographed during the con- trolled impact and the existing lunar terrain data. Test results from this new method also validate the published impact site po sition.展开更多
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-Q11-02)the National Natural Science Foundation of China (Nos. 41006114, 40890151)+1 种基金the National Basic Research Program of China (973 Program) (No. 2012CB417401)the SOA Key Laboratory for Polar Science (No. KP201103)
文摘The relationship between heat content and the interannual time scale is examined with satellite sea surface height （SSH） in the global ocean on altimeter measurements, historical hydrography, and model assimilation outputs. Results show that correlation between altimetric SSH and heat content in the upper 700 m calculated from Ishii data is geographically nonuniform. In the tropical ocean, heat content and SSH are strongly correlated and exhibit nearly the same interannual variations. In the polar ocean, their correlation is relatively weak. Further analysis with Simple Ocean Data Assimilation outputs shows that such nonuniform distribution is not from dynamical origin but from the limited integral depth selected to calculate heat content. The integral depth of 700 m is inadequate to capture variation of the deep main thermocline in the polar region. The halosteric effect also contributes to the nonuniform pattern of correlation, because saline contraction becomes significant in the polar ocean owing to low temperature.
文摘This paper compares the differences between the mathematical model in graph theory and GIS network analysis model. Thus it claims that the GIS network analysis model needs to solve. Then this paper introduces the spatial data management methods in object\|relation database for GIS and discusses its effects on the network analysis model. Finally it puts forward the GIS network analysis model based on the object\|relation database. The structure of the model is introduced in detail and research is done to the internal and external memory data structure of the model. The results show that it performs well in practice.
文摘The map of reflecting horizon A, plotted on the basis of regional geophysical materials, yieldsinformation about the bottom topography of sedimentary cover of the West-Siberian Basin within Nadym-Taz interfluve. Through morphotectonic analysis about this surface, the authors are able tounderstand the distribution characteristics of the main topographic irregularities, with the blockstructure of the lower cover floors and underlying complexes as the focus.The largest irregularities are caused by the presence of three regional altitude steps, which show a regional tendency of basement being submerged in the north-north-east direction. Within these irregularities, the authors have distinguished some regions, which can be divided, based on the characteristics of morphostructural distribution, into two groups, i.e., areal (Nadym, Tol'ka, Urengoy)and belt (Tarko-Sale, Russko-Chasel'ka and Messoyakha). The first ones represent quasihomogeneous blocks, whose surfaces are complicated by irregular low-amplitude elevations and troughs and low-gradient zones with gradient values being up to 0.03, or they submerge stepwise, with the leveled areas being separated by zones with high gradients (0.07-0.15). The morphostructure of the other group of regions is characterized by the en-echelon distribution of contrastingly positive and negative elements with high values of slope gradients (higher than 0.1-0.2).
文摘Human economic and social needs can be in conflict with ecosystem needs. Land development increases impervious surfaces causing significant negative impacts to aquatic ecosystems. Many impervious surface estimates are derived from remote sensing data, developed by using different methods and often out of date. Remote sensing data is often at scales applicable to regional management, but not local planning decisions. To date, no standardized annual dataset of percent impervious surface exists for use at both local and watershed scales. Effective communication between natural resource managers and local planners has been lacking. One solution is to monitor percent impervious surface with a relative index rather than direct measure. A relative index model can use a currency, like foundation square feet per hectare, which is useful for all decision makers. One data source for developing a relative index of impervious surface is property tax data. These data document annual land development at local scale. Here, the author presents the use of Maryland property tax data to index land development and percent impervious surface.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40871177 and 41171332)the Knowledge Innovation Project of the Institute of Geographic and Natural Resources Research, the Chinese Academy of Sci-ences (Grant No. 201001005)
文摘The distribution characteristics of the impact craters can provide a large amount of information on impact history and the lunar evolution process. In this research, based on the digital elevation model （DEM） data originating from Change＇E-1 CCD stereo camera, three automatic extraction methods for the impact craters are implemented in two research areas： direct extraction from flooded DEM data （the Flooded method）, object-oriented extraction from DEM data by using ENVI ZOOM function （the Object-Oriented method） and novel object-oriented extraction from flooded DEM data （the Flooded Object-Oriented method）. Accuracy assessment, extracted degree computation, cumulative frequency analysis, shape and age analysis of the extracted craters combined display the following results. （1） The Flooded Object-Oriented method yields better accuracy than the other two methods in the two research areas; the extraction result of the Flooded method offers the similar accuracy to that of the Object-Oriented method. （2） The cumulative frequency curves for the extracted craters and the confirmed craters share a simi- lar change trajectory. （3） The number of the impact craters extracted by the three methods in the Imbrian period is the largest and is of various types; as to their age earlier than lmbrain, it is difficult to extract because they could have been destroyed.
基金supported by National Natural Science Foundation of China (Grant No. 10903017)National High Technology Research and Development Program of China (Grant No. 2010AA122202)
文摘Up to now, many lunar explorations concluded their scientific mission through the impact on the lunar surface. The prediction and positioning of impact sites are based on the extrapolated orbiting data together with the real time orbiting data and observations from ground based telescope provided by TT ＆ C System. As most lunar missions carded cameras onboard, a new method of positioning of CE-1 impact site is put forward. It is based on the CCD image data photographed during the con- trolled impact and the existing lunar terrain data. Test results from this new method also validate the published impact site po sition.
