In mid-May,good news came from Tajikistan,the country of high mountains.The Tajikistan Bogda Mountain geological exploration and sampling project,which had been dormant for over a decade,achieved a key breakthrough af...In mid-May,good news came from Tajikistan,the country of high mountains.The Tajikistan Bogda Mountain geological exploration and sampling project,which had been dormant for over a decade,achieved a key breakthrough after years of careful research,multi-party collaboration,and optimization of various plans,launching a new round of field exploration and testing work.展开更多
Complicated oil and gas fields occupy an important position in oil and gas exploration. In this paper, complicated oil and gas fields are grouped into four types: fault-block, lithologic, stratigraphic and fissure typ...Complicated oil and gas fields occupy an important position in oil and gas exploration. In this paper, complicated oil and gas fields are grouped into four types: fault-block, lithologic, stratigraphic and fissure types. On the basis of the new theory of petroleum geological exploration in composite oil and gas accumulation areas within continental basins, a new exploration sequence suitable for complicated oil and gas fields has been established, which comprises four stages:(1) initial exploration;(2) preliminary exploration;(3) early step-by-step exploration and development: and(4) late step-by-step exploration and development. The idea of cybernetics has been taken to control various links of a systematic exploration project so as to fully, effectively and comprehensively utilize the new exploration techniques, eventually realizing the optimization of exploration with the aim of raising the efficiency of exploration of complicated oil and gas fields.展开更多
To construct a giant Sichuan gas province,it is in an urgent need of exploring new replacement areas with abundant natural gas resources and great exploration potential.In this paper,the formation conditions(e.g.sourc...To construct a giant Sichuan gas province,it is in an urgent need of exploring new replacement areas with abundant natural gas resources and great exploration potential.In this paper,the formation conditions(e.g.source rock,reservoir and play)and the distribution laws of the deep-seated old giant marine carbonate oil/gasfields in China's Craton Basins were investigated systematically.Then,the accumulation and enrichment conditions of deep Sinian natural gas in the Sichuan Basin were analyzed.Finally,potential and favorable target zones of natural gas exploration in the Dengying Formation of Upper Sinian were evaluated.And the following research results were obtained.Firstly,the effec-tiveness and scale of source kitchens,reservoirs and reservoirecaprock assemblages and the proximity are the necessary conditions for the formation of deep-seated giant carbonate oil/gasfields,and paleo-uplifts,paleo-slopes and paleo-fault zones are the favorable areas of searching deep-seated giant carbonate oil/gasfields.Secondly,in the Sichuan Basin,three sets of high-quality source rocks are developed in the NeoproterozoiceCambrian System,and their maturity of organic matter is still in the optimal window for cracking gas,so the gas generation scale is large.Thirdly,after the microbial carbonate rocks of Dengying Formation in the Sichuan Basin were reconstructed by constructive diagenesis,effective reservoirs are formed and distributed widely.Fourthly,owing to the integrated source rocks and cap rocks of Dengying Formation,the marginal platform and the intra platform have favorable conditions for proximal hydrocarbon accumulation.In conclusion,the deep Sinian in the Sichuan Basin has good conditions of hydrocarbon accumulation and it is an important replacement area of natural gas exploration.Paleo-uplifts and slopes in the central Sichuan Basin have been the favorable locations of natural gas accumulation for a long period.Large-scale exploration shall focus on four favorable areas,including the marginal platform zone in the fourth member of Dengying Formation,the marginal platform zone in the second member of Dengying Formation,the bioherm shoalbody of Dengying Formation intra platform in the paleo-uplifts and slopes of the central Sichuan Basin,and the bioherm shoalbody of Dengying Formation in the eastern Sichuan Basin.展开更多
A correct understanding of organic matter abundance is key to understanding the conditions necessary for generating biogenic gas,seeking favorable exploration intervals and fields and evaluating resources correctly.Th...A correct understanding of organic matter abundance is key to understanding the conditions necessary for generating biogenic gas,seeking favorable exploration intervals and fields and evaluating resources correctly.The Qigequan Formation shale of the Quaternary in the Sanhu Depression of the Qaidam Basin is taken as the research object.The abundance of dissolved organic matter was determined through total carbon,pyrolysis and other experiments.The evaluation criteria were established and applied.The resource quality is calculated.The results are as follows.(1)Dissolved organic matter is the basis for biogenic gas generation and should be emphasized in the evaluation.(2)The shale has a relatively high dissolved organic carbon(DOC)content,with an average of 2.48 times that of insoluble organic carbon.(3)The DOC of the good source rock is more than 0.60%,that of the medium is 0.25~0.60%,and that of the poor is less than 0.25%.(4)The distribution of good source rocks is influenced by the position and depth of the water column and the paleoclimate.Favorable intervals are mainly in the upper sections of K10,K9 and K8 and the middle section of K7.The favorable areas are mainly the Tainan,Sebei and Sedong areas.展开更多
Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid heigh...Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment （GRACE） and future GRACE Follow-On missions is established based on the semi-analytical method, and the Earth＇s gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer （GOCE） mission is recovered by the space-time-wise approach. Secondly, the cumulative geoid height errors are 1.727 × 10^-1 m, 1.839 × 10^-1 m and 9.025 × 10^ -2 m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP, GRACE and GOCE, which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03S, EICEN-GRACE02S and GO_CONS GCF 2 DIR R1. The cumulative geoid height error is 6.847 × 10 ^-2 m at degree 250 from the future GRACE Follow-On mission. Finally, the complementarity among the four-stage satellite gravity missions including CHAMP, GRACE, GOCE and GRACE Follow-On is demonstrated contrastively.展开更多
On 28 th July 2018,a massive landslide occurred in a mountainous area in Northern Thailand.The landslide after ten days of heavy rainfall generated the movement of uphill mountain soil into the populated village.This ...On 28 th July 2018,a massive landslide occurred in a mountainous area in Northern Thailand.The landslide after ten days of heavy rainfall generated the movement of uphill mountain soil into the populated village.This study presents a comprehensive failure analysis of local rainfallinduced landslides based on topographical and geological information.Rainfall measurement data were gathered from two rainfall stations close to the study area.The rainfall records show that the total monthly rainfalls in 2018 were significantly higher than the average monthly rainfalls over the past decade.Site investigation started with an unmanned aerial photogrammetric survey to generate a digital elevation model.Then,dynamic probing test,microtremor survey,and electrical resistivity survey were carried out along undisturbed soils beside the failed slope to evaluate the thickness of the soft soil cover on top of the rock basement.During the site survey,residual soil samples were collected to determine engineering properties in the laboratory.Finally,a slope stability analysis was performed to assess the landslide hazard based on the results of aerial photogrammetric survey,field exploration,and laboratory tests.The slope stability analysis and rainfall records revealed that the Huay Khab landslide was mainly caused by an increase in the water content of residual soils due to the prolonged rainfall which led to a sharp decrease in the shear strength.This leads to the conclusion that the proposed landslide investigation program could be used to assess the potential of landslide failure due to prolonged rainfall on a local scale.展开更多
The basic principle of spectral combination method is discussed,and the general expressions of the spectral weight and spectral combination of the united-processing of various types of gravimetric data are shown.What...The basic principle of spectral combination method is discussed,and the general expressions of the spectral weight and spectral combination of the united-processing of various types of gravimetric data are shown.What＇s more,based on degree error RMS of potential coefficients,the detailed expressions of spectral combination formulae and the corresponding spectral weights in the Earth＇s gravitational field model（EGM） determination using GOCE ＋ GRACE and CHAMP ＋ GRACE ＋ GOCE are derived.The fundamental situation that ulux-champ2013 s,tongji-GRACE01,go-cons-gcf-2-tim-r5 constructed respectively by CHAMP,GRACE,GOCE data and go-cons-gcf-2-dir-r5 constructed by syncretic processing of GRACE,GOCE and LAGEOS data are explained briefly,the degree error RMS,cumulative geoid height error and cumulative gravity anomaly error of these models are calculated.A syncretic model constructed from CHAMP,GRACE and GOCE data,which is expressed by champ ＋ grace ＋ goce,is obtained based on spectral combination method.Experimentation results show that the precision of CHAMP data model is the lowest in satellite-only models,so it is not needed in the determination of syncretic models.The GRACE data model can improve the GOCE data model in medium-long wavelength,so the overall precision of syncretic model can be improved.Consequently,as many types of gravimetric data as possible should be combined together in the data processing in order to strengthen the quality and reliability with widening scope and improve the precision and spatial resolution of the computational results.展开更多
The Ecuador Mw - 7.8 earthquake on April 16, 2016, ruptured a nearly 200 km long zone along the plate interface between Nazca and South American plates which is coincident with a seismic gap since 1942, when a Mw - 7....The Ecuador Mw - 7.8 earthquake on April 16, 2016, ruptured a nearly 200 km long zone along the plate interface between Nazca and South American plates which is coincident with a seismic gap since 1942, when a Mw - 7.8 earthquake happened. This earthquake occurred at a margin characterized by moderately big to giant earthquakes such as the 1906 （Mw 8.8）. A heavily sedimented trench explains the abnormal lengths of the rupture zones in this system as inhibits the role of natural barriers on the propagation of rupture zones. High amount of sediment thickness is associated with tropical climates, high erosion rates and eastward Pacific dominant winds that provoke orographic rainfalls over the Pacific slope of the Ecuatorian Andes. Offshore sediment dispersion off the oceanic trench is controlled by a close arrangement of two aseismic ridges that hit the Costa Rico and South Ecuador margin respectively and a mid ocean ridge that separates the Cocos and Nazca plate trapping sediments. Gravity field and Ocean Circulation Explorer （GOCE） satellite data are used in this work to test the possible relationship between gravity signal and earthquake rupture structure as well as registered aftershock seismic activity. Reduced vertical gravity gradient shows a good correlation with rupture structure for certain degrees of the harmonic expansion and related depth of the causative mass; indicating, such as in other analyzed cases along the subduction margin, that fore-arc structure derived from density heterogeneities explains at a certain extent propagation of the rupture zones. In this analysis the rupture zone of the April 2016 Ecuador earthquake developed through a relatively low density zone of the fore-arc sliver. Finally, aftershock sequence nucleated around the area of maximum slips in the rupture zone, suggesting that heterogeneous density structure of the fore-arc determined from gravity data could be used in forecasting potential damaged zones associated with big ruptures along the subduction border.展开更多
How to deal with colored noises of GOCE （Gravity field and steady - state Ocean Circulation Explorer） satellite has been the key to data processing. This paper focused on colored noises of GOCE gradient data and the...How to deal with colored noises of GOCE （Gravity field and steady - state Ocean Circulation Explorer） satellite has been the key to data processing. This paper focused on colored noises of GOCE gradient data and the frequency spectrum analysis. According to the analysis results, gravity field model of the optima] degrees 90-240 is given, which is recovered by COCE gradient data. This paper presents an iterative Wiener filtering method based on the gravity gradient invariants. By this method a degree-220 model was calculated from GOCE SGG （Satellite Gravity Gradient） data. The degrees above 90 of ITG2010 were taken as the prior gravity field model, replacing the low degree gravity field model calculated by GOCE orbit data. GOCE gradient colored noises was processed by Wiener filtering. Finally by Wiener filtering iterative calculation, the gravity field model was restored by space-wise harmonic analysis method. The results show that the model＇s accuracy matched well with the ESA＇s （European Space Agency） results by using the same data,展开更多
Cultures throughout the world are associating with the rivers.People depend upon the rivers and their tributaries for food,water,transport,and many other aspects of their daily lives.Unfortunately,human beings have no...Cultures throughout the world are associating with the rivers.People depend upon the rivers and their tributaries for food,water,transport,and many other aspects of their daily lives.Unfortunately,human beings have not calculated the accurate lengths for the great rivers even today.The lengths of the rivers are very different in popular textbooks,magazines,atlases and encyclopedias,etc.To accurately determine the lengths of the principal rivers of the world,the combination of satellite image analysis and field investigations to the source regions is proposed in this paper.The lengths of the Nile,Amazon,Yangtze,Mississippi,Yellow,Ob,Yenisey,Amur,Congo and Mekong,with lengths over or close to 5000 km,were calculated using the proposed method.The results may represent the most reliable and accurate lengths of the principal rivers of the world that are currently achievable.展开更多
文摘In mid-May,good news came from Tajikistan,the country of high mountains.The Tajikistan Bogda Mountain geological exploration and sampling project,which had been dormant for over a decade,achieved a key breakthrough after years of careful research,multi-party collaboration,and optimization of various plans,launching a new round of field exploration and testing work.
文摘Complicated oil and gas fields occupy an important position in oil and gas exploration. In this paper, complicated oil and gas fields are grouped into four types: fault-block, lithologic, stratigraphic and fissure types. On the basis of the new theory of petroleum geological exploration in composite oil and gas accumulation areas within continental basins, a new exploration sequence suitable for complicated oil and gas fields has been established, which comprises four stages:(1) initial exploration;(2) preliminary exploration;(3) early step-by-step exploration and development: and(4) late step-by-step exploration and development. The idea of cybernetics has been taken to control various links of a systematic exploration project so as to fully, effectively and comprehensively utilize the new exploration techniques, eventually realizing the optimization of exploration with the aim of raising the efficiency of exploration of complicated oil and gas fields.
基金supported by the National Major Science and Technology Project"Hydrocarbon accumulation,key techniques and target evaluation of carbon-ate rocks in Lower Paleozoic-Pre-Cambrian"(No.2016ZX05004).
文摘To construct a giant Sichuan gas province,it is in an urgent need of exploring new replacement areas with abundant natural gas resources and great exploration potential.In this paper,the formation conditions(e.g.source rock,reservoir and play)and the distribution laws of the deep-seated old giant marine carbonate oil/gasfields in China's Craton Basins were investigated systematically.Then,the accumulation and enrichment conditions of deep Sinian natural gas in the Sichuan Basin were analyzed.Finally,potential and favorable target zones of natural gas exploration in the Dengying Formation of Upper Sinian were evaluated.And the following research results were obtained.Firstly,the effec-tiveness and scale of source kitchens,reservoirs and reservoirecaprock assemblages and the proximity are the necessary conditions for the formation of deep-seated giant carbonate oil/gasfields,and paleo-uplifts,paleo-slopes and paleo-fault zones are the favorable areas of searching deep-seated giant carbonate oil/gasfields.Secondly,in the Sichuan Basin,three sets of high-quality source rocks are developed in the NeoproterozoiceCambrian System,and their maturity of organic matter is still in the optimal window for cracking gas,so the gas generation scale is large.Thirdly,after the microbial carbonate rocks of Dengying Formation in the Sichuan Basin were reconstructed by constructive diagenesis,effective reservoirs are formed and distributed widely.Fourthly,owing to the integrated source rocks and cap rocks of Dengying Formation,the marginal platform and the intra platform have favorable conditions for proximal hydrocarbon accumulation.In conclusion,the deep Sinian in the Sichuan Basin has good conditions of hydrocarbon accumulation and it is an important replacement area of natural gas exploration.Paleo-uplifts and slopes in the central Sichuan Basin have been the favorable locations of natural gas accumulation for a long period.Large-scale exploration shall focus on four favorable areas,including the marginal platform zone in the fourth member of Dengying Formation,the marginal platform zone in the second member of Dengying Formation,the bioherm shoalbody of Dengying Formation intra platform in the paleo-uplifts and slopes of the central Sichuan Basin,and the bioherm shoalbody of Dengying Formation in the eastern Sichuan Basin.
基金supported by the Natural Science Foundation of China(No.41872135)the China Scholarship Council.
文摘A correct understanding of organic matter abundance is key to understanding the conditions necessary for generating biogenic gas,seeking favorable exploration intervals and fields and evaluating resources correctly.The Qigequan Formation shale of the Quaternary in the Sanhu Depression of the Qaidam Basin is taken as the research object.The abundance of dissolved organic matter was determined through total carbon,pyrolysis and other experiments.The evaluation criteria were established and applied.The resource quality is calculated.The results are as follows.(1)Dissolved organic matter is the basis for biogenic gas generation and should be emphasized in the evaluation.(2)The shale has a relatively high dissolved organic carbon(DOC)content,with an average of 2.48 times that of insoluble organic carbon.(3)The DOC of the good source rock is more than 0.60%,that of the medium is 0.25~0.60%,and that of the poor is less than 0.25%.(4)The distribution of good source rocks is influenced by the position and depth of the water column and the paleoclimate.Favorable intervals are mainly in the upper sections of K10,K9 and K8 and the middle section of K7.The favorable areas are mainly the Tainan,Sebei and Sedong areas.
基金supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences for Distinguished Young Scholar(KZCX2-EW-QN114)the National Natural Science Foundation of China(41004006,41131067,11173049 and 41274041)+7 种基金the Merit-based Scientific Research Foundation of the State Ministry of Human Resources and Social Security of China for Returned Overseas Chinese Scholars(Z01101)the Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,China(11-01-02)the Open Research Fund Program of the Key Laboratory of Geo-Informatics of National Administration of Surveying,Mapping and Geoinformation of China(201322)the Open Research Fund Program of the State Key Laboratory of Geoinformation Engineering,China(SKLGIE2013-M-1-5)the Main Direction Program of Institute of Geodesy and Geophysics,Chinese Academy of Sciences(Y309451045)the Research Fund Program of State Key Laboratory of Geodesy and Earth's Dynamics,China(Y309491050)the Research Fund of the National Civilian Space Infrastructure Project(Y419341034)the Research Fund of the Lu Jiaxi Young Talent and the Youth Innovation Promotion Association of Chinese Academy of Science(Y305171017)
文摘Firstly, the Earth＇s gravitational field from the past Challenging Minisatellite Payload （CHAMP） mission is determined using the energy conservation principle, the combined error model of the cumulative geoid height influenced by three instrument errors from the current Gravity Recovery and Climate Experiment （GRACE） and future GRACE Follow-On missions is established based on the semi-analytical method, and the Earth＇s gravitational field from the executed Gravity Field and Steady-State Ocean Circulation Explorer （GOCE） mission is recovered by the space-time-wise approach. Secondly, the cumulative geoid height errors are 1.727 × 10^-1 m, 1.839 × 10^-1 m and 9.025 × 10^ -2 m at degrees 70,120 and 250 from the implemented three-stage satellite gravity missions consisting of CHAMP, GRACE and GOCE, which preferably accord with those from the existing earth gravity field models involving EIGEN-CHAMP03S, EICEN-GRACE02S and GO_CONS GCF 2 DIR R1. The cumulative geoid height error is 6.847 × 10 ^-2 m at degree 250 from the future GRACE Follow-On mission. Finally, the complementarity among the four-stage satellite gravity missions including CHAMP, GRACE, GOCE and GRACE Follow-On is demonstrated contrastively.
基金supported by National Research Council of Thailand(NRCT):NRCT5RSA63001-05the Ratchadapisek Sompoch Endowment Fund(2021),Chulalongkorn University(764002-ENV)+1 种基金Grants for Development of New Faculty Staff,Ratchadaphiseksomphot Endowment Fund,Chulalongkorn University,Thailandthe C2F Fund for Postdoctoral Fellowship,Chulalongkorn University,Thailand。
文摘On 28 th July 2018,a massive landslide occurred in a mountainous area in Northern Thailand.The landslide after ten days of heavy rainfall generated the movement of uphill mountain soil into the populated village.This study presents a comprehensive failure analysis of local rainfallinduced landslides based on topographical and geological information.Rainfall measurement data were gathered from two rainfall stations close to the study area.The rainfall records show that the total monthly rainfalls in 2018 were significantly higher than the average monthly rainfalls over the past decade.Site investigation started with an unmanned aerial photogrammetric survey to generate a digital elevation model.Then,dynamic probing test,microtremor survey,and electrical resistivity survey were carried out along undisturbed soils beside the failed slope to evaluate the thickness of the soft soil cover on top of the rock basement.During the site survey,residual soil samples were collected to determine engineering properties in the laboratory.Finally,a slope stability analysis was performed to assess the landslide hazard based on the results of aerial photogrammetric survey,field exploration,and laboratory tests.The slope stability analysis and rainfall records revealed that the Huay Khab landslide was mainly caused by an increase in the water content of residual soils due to the prolonged rainfall which led to a sharp decrease in the shear strength.This leads to the conclusion that the proposed landslide investigation program could be used to assess the potential of landslide failure due to prolonged rainfall on a local scale.
基金supported by the National Natural Science Foundation of China(41304022)the National 973 Foundation(61322201,2013CB733303)the Youth Innovation Foundation of High Resolution Earth Observation(GFZX04060103-5-12)
文摘The basic principle of spectral combination method is discussed,and the general expressions of the spectral weight and spectral combination of the united-processing of various types of gravimetric data are shown.What＇s more,based on degree error RMS of potential coefficients,the detailed expressions of spectral combination formulae and the corresponding spectral weights in the Earth＇s gravitational field model（EGM） determination using GOCE ＋ GRACE and CHAMP ＋ GRACE ＋ GOCE are derived.The fundamental situation that ulux-champ2013 s,tongji-GRACE01,go-cons-gcf-2-tim-r5 constructed respectively by CHAMP,GRACE,GOCE data and go-cons-gcf-2-dir-r5 constructed by syncretic processing of GRACE,GOCE and LAGEOS data are explained briefly,the degree error RMS,cumulative geoid height error and cumulative gravity anomaly error of these models are calculated.A syncretic model constructed from CHAMP,GRACE and GOCE data,which is expressed by champ ＋ grace ＋ goce,is obtained based on spectral combination method.Experimentation results show that the precision of CHAMP data model is the lowest in satellite-only models,so it is not needed in the determination of syncretic models.The GRACE data model can improve the GOCE data model in medium-long wavelength,so the overall precision of syncretic model can be improved.Consequently,as many types of gravimetric data as possible should be combined together in the data processing in order to strengthen the quality and reliability with widening scope and improve the precision and spatial resolution of the computational results.
文摘The Ecuador Mw - 7.8 earthquake on April 16, 2016, ruptured a nearly 200 km long zone along the plate interface between Nazca and South American plates which is coincident with a seismic gap since 1942, when a Mw - 7.8 earthquake happened. This earthquake occurred at a margin characterized by moderately big to giant earthquakes such as the 1906 （Mw 8.8）. A heavily sedimented trench explains the abnormal lengths of the rupture zones in this system as inhibits the role of natural barriers on the propagation of rupture zones. High amount of sediment thickness is associated with tropical climates, high erosion rates and eastward Pacific dominant winds that provoke orographic rainfalls over the Pacific slope of the Ecuatorian Andes. Offshore sediment dispersion off the oceanic trench is controlled by a close arrangement of two aseismic ridges that hit the Costa Rico and South Ecuador margin respectively and a mid ocean ridge that separates the Cocos and Nazca plate trapping sediments. Gravity field and Ocean Circulation Explorer （GOCE） satellite data are used in this work to test the possible relationship between gravity signal and earthquake rupture structure as well as registered aftershock seismic activity. Reduced vertical gravity gradient shows a good correlation with rupture structure for certain degrees of the harmonic expansion and related depth of the causative mass; indicating, such as in other analyzed cases along the subduction margin, that fore-arc structure derived from density heterogeneities explains at a certain extent propagation of the rupture zones. In this analysis the rupture zone of the April 2016 Ecuador earthquake developed through a relatively low density zone of the fore-arc sliver. Finally, aftershock sequence nucleated around the area of maximum slips in the rupture zone, suggesting that heterogeneous density structure of the fore-arc determined from gravity data could be used in forecasting potential damaged zones associated with big ruptures along the subduction border.
基金supported by the National Natural Science Foundation of China(41404020)
文摘How to deal with colored noises of GOCE （Gravity field and steady - state Ocean Circulation Explorer） satellite has been the key to data processing. This paper focused on colored noises of GOCE gradient data and the frequency spectrum analysis. According to the analysis results, gravity field model of the optima] degrees 90-240 is given, which is recovered by COCE gradient data. This paper presents an iterative Wiener filtering method based on the gravity gradient invariants. By this method a degree-220 model was calculated from GOCE SGG （Satellite Gravity Gradient） data. The degrees above 90 of ITG2010 were taken as the prior gravity field model, replacing the low degree gravity field model calculated by GOCE orbit data. GOCE gradient colored noises was processed by Wiener filtering. Finally by Wiener filtering iterative calculation, the gravity field model was restored by space-wise harmonic analysis method. The results show that the model＇s accuracy matched well with the ESA＇s （European Space Agency） results by using the same data,
基金supported by China High-Tech Research and Development Project(863 Project)the Innovation Project of Chinese Academy of Sciences,the Special Funds of Director General of Institute of Remote Sensing Applications,Chinese Academy of Sciences,the Funds of the State Key Laboratory of Remote Sensing Sciences of Chinathe Funds of the State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing of China and Earth&Space Awards of the Earth and Space Foundation.
文摘Cultures throughout the world are associating with the rivers.People depend upon the rivers and their tributaries for food,water,transport,and many other aspects of their daily lives.Unfortunately,human beings have not calculated the accurate lengths for the great rivers even today.The lengths of the rivers are very different in popular textbooks,magazines,atlases and encyclopedias,etc.To accurately determine the lengths of the principal rivers of the world,the combination of satellite image analysis and field investigations to the source regions is proposed in this paper.The lengths of the Nile,Amazon,Yangtze,Mississippi,Yellow,Ob,Yenisey,Amur,Congo and Mekong,with lengths over or close to 5000 km,were calculated using the proposed method.The results may represent the most reliable and accurate lengths of the principal rivers of the world that are currently achievable.
