0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,...0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,87.45°E,with a depth of~10 km.展开更多
The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,glob...The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,global warming,and the management of freshwater resources.It is also essential for the early warnings of hazards caused by ice avalanches.SAR imaging geodesy has been developed for measuring glacier velocity,especially the pixel-offset tracking method.This paper introduces some basic concepts of glaciology and principles of various SAR imaging geodesy methods,with a detailed presentation about the developments in the applications of the pixel-offset tracking method.Finally,the challenges and future prospects of SAR imaging geodesy in glacier monitoring are discussed.展开更多
The geodesy discipline has been evolving and constantly intersecting and merging with other disciplines in the last 50 years,due to the continuous progress of geodetic observation techniques and expansion of applicati...The geodesy discipline has been evolving and constantly intersecting and merging with other disciplines in the last 50 years,due to the continuous progress of geodetic observation techniques and expansion of application fields.This paper first introduces the development and roles of geodesy and its formation.Secondly,the development status of geodesy discipline is analyzed from the progress of observation techniques and cross-discipline formation is analyzed from the expansion of application fields.Furthermore,the development trend of geodesy is stated from the perspective of national requirements and scientific developments.Finally,the sub-disciplines for geodesy are suggested at the present stage,based on the requirements of the National Natural Science Foundation of China and development status of geodesy itself,which can provide references for topic selection and fund application of geodetic scientific research.展开更多
Modern geodetic techniques have developed rapidly in recent years, providing reliable observation data and new effective approaches, and greatly enhancing studies of the Tibetan geodynamics. For instance, the well-kno...Modern geodetic techniques have developed rapidly in recent years, providing reliable observation data and new effective approaches, and greatly enhancing studies of the Tibetan geodynamics. For instance, the well-known GPS technique has been employed to measure seismic slips for many faults in the Tibetan Plateau. GPS data agree well with the hypothesis of a thickening crust and eastward mass flow. Moreover, absolute gravimetric data have been applied to interpret geophysical phenomena such as crust movement, co-seismic gravity change, GIA, and ground water change. The satellite gravity mission GRACE launched in 2002 provided global gravity models with unprecedentedly high precision and high spatial resolution. It has been used in implementing temporal gravity changes and improving our knowledge of the Earth＇s interior, including lithosphere dynamics, mantle viscosity and rheology, plateau uplift, and subduction processing. It is noteworthy that gravity presents unique advantages for the study of Tibetan geodynamics because of its sensitivity to mass migration and dynamic redistribution. To date, great advances have been made in applying modern geodetic data in studying dynamic changes of Tibetan plateau. For instance, the horizontal displacement field from GPS data revealed dynamical characteristics of the present-day Tibetan plateau. The combination of gravity anomalies and topographic data describe the tectonic characteristics of Tibetan plateau. The combination of gravity data and GPS data show present properties of the Tibetan plateau such as crust thickening, Moho＇s subsidence, and plateau uplift. GRACE data were used to estimate the distribution of ice/snow melting. These results demonstrate that mere application of integrated geodetic data as well as geophysical methods and numerical simulations can enhance our knowledge of Tibetan plateau dynamics. It must be pointed out that GRACE data include various geophysical signals such as crust vertical movement, denudation, ice and snow melting, GIA, ground water change, and permafrost degradation. To separate the tectonic information from other impulses, each physical signal must be evaluated and corrected carefully from the GRACE data. The Tibetan geodynamic problem is a complicated and synthetic issue that must be addressed through collaboration of workers in many fields. Succinctly put, although great achievements have been made in studying Tibetan plateau dynamics from each field, the dynamical process remains unclear. Some fundamental problems remain unresolved. They should be solved with modern geodetic data, such as GRACE, GPS, and absolute gravity data, combined with meteorological and geological data, for quantitative analysis of Tibetan plateau dynamics affected by respective geophysical sources. This review article introduces and discusses the scientific importance, advances, problems, and prospects of modern geodesy applied to the study of geodynamic changes of the Tibetan plateau.展开更多
With the advanced development of the modern geodetic techniques, the geodetic obser- vations have been proved to be more powerful to uncover the geophysical phenomena, especially the seismic one, than that in the past...With the advanced development of the modern geodetic techniques, the geodetic obser- vations have been proved to be more powerful to uncover the geophysical phenomena, especially the seismic one, than that in the past time. The recent developments and achievements in the seismological geodesy are summarised here. Several popular geodetic techniques, such as high-rate GNSS, InSAR and Satellite Gravimetry, are introduced first to present their recent contributions in studying the seismic deformations. The developments of the joint inversion of the seismic source parameters from multiple observations are then highlighted. Some outlooks in seismological geodesy are presented in the end.展开更多
The ocean accounts for approximately 71%of the total area of the Earth.Whether it is studying the shape of the Earth itself through geodesy or the future development of earth system science,strengthening the construct...The ocean accounts for approximately 71%of the total area of the Earth.Whether it is studying the shape of the Earth itself through geodesy or the future development of earth system science,strengthening the construction of ocean geodesy disciplines and innovating ocean geodetic observation technologies have evident theoretical and practical significance.In recent years,the discipline of ocean geodesy in China has been continuously developing and growing,and notable breakthroughs have been made in ocean satellite geodesy and seafloor geodetic observation technology.Research on ocean geodetic observation models and algorithms has also made great progress.展开更多
To overcome the high cost of learning,non-visual operation,and cumbersome steps of fine-tuning map elements in Generic Mapping Tools(GMT)and other geoscience mapping softwares,we present the Tectonic Geodesy Applicati...To overcome the high cost of learning,non-visual operation,and cumbersome steps of fine-tuning map elements in Generic Mapping Tools(GMT)and other geoscience mapping softwares,we present the Tectonic Geodesy Application(TGA),a user-friendly 64-bit tectonic geodesy mapping software based on the secondary development interface of the open source geographic information system QGIS.In this paper,we detailly introduce the architecture and function modules of our software,and highlight the functions of rendering and map decoration through four cases:the geologic map of Papua New Guinea,the seismicity in China and surrounding regions,the seismicity and crustal deformation of the Tibetan Plateau and the coseismic deformation of the 2017 Jiuzhaigou earthquake in China.Compared with GMT,the tectonic geodesy mapping software we developed has the advantages of simple operation,low learning cost and user-friendly interface.展开更多
The convergent and divergent velocities of active plate boundaries in the North Hemisphere are obtained with space geodetic data. The relative motions of adjacent plates in north-south direction are almost convergent;...The convergent and divergent velocities of active plate boundaries in the North Hemisphere are obtained with space geodetic data. The relative motions of adjacent plates in north-south direction are almost convergent; the spreading rates of the north mid-Atlantic ridge are smaller than the south mid-Atlantic ridge; the closed differences of the baseline length rates between stations on different plates along the latitudinal circle of 7.7, 23.3? 34.8? 42.0?and 51.0?are all negative. All these show that the North Hemisphere is a compressive hemisphere.展开更多
Research of the practical 4-D integrated geodesy(IG) and strain analysis is presented in this paper.The practical model and basic observation equation are established by using IG and dynamic adjustment.Furthermore,the...Research of the practical 4-D integrated geodesy(IG) and strain analysis is presented in this paper.The practical model and basic observation equation are established by using IG and dynamic adjustment.Furthermore,the observation equations about gravity vector,zenith distance,azimuth angle,difference are derived and determination of local gravity field covariance solved.The 3-D strain formular is derived and the strain parameters calculated from it.The improvement of the OPERA software of Landan and Hem etc,FRG has been done to get a new software in Fortran Language which implements in MASSCOMP computer.Using the software,the integrated adjustment of two term observation data of triangle chain, triangle net,gravity,level,astronomic observation and strain analysis are established.The result is satisfactory.展开更多
The fictitious compress recovery approach is introduced, which could be applied to the establishment of the Rungerarup theorem, the determination of the Bjerhammar＇s fictitious gravity anomaly, the solution of the ＂...The fictitious compress recovery approach is introduced, which could be applied to the establishment of the Rungerarup theorem, the determination of the Bjerhammar＇s fictitious gravity anomaly, the solution of the ＂downward con- tinuation＂ problem of the gravity field, the confirmation of the convergence of the spherical harmonic expansion series of the Earth＇s potential field, and the gravity field determination in three cases： gravitational potential case, gravitation case, and gravitational gradient case. Several tests using simulation experiments show that the fictitious compress recovery approach shows promise in physical geodesy applications.展开更多
"Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opport..."Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opportunity for participants from Canada and from around the world to come together and share their science and culture.2019 marks the 100th anniversary of IUGG;we will look back on the accomplishments of the previous century of Earth and space science research,and forward to the next century of scientific advancement.Join us for a host of scientific activities,including special public lectures,keynote Union lectures and a wide variety of themed sessions.展开更多
UNAVCO supports geoscience research at 113 US academic Member institutions,and another 104 Associate Member institutions include international universities,laboratories,observatories,academies of science,and a museum....UNAVCO supports geoscience research at 113 US academic Member institutions,and another 104 Associate Member institutions include international universities,laboratories,observatories,academies of science,and a museum.This diverse membership shares UNAVCO’s purpose at home and abroad,giving UNAVCO global reach in advancing geodesy.Since the mid-1980s,modern geodesy has evolved into a cutting-edge,multi-faceted toolbox with remarkably diverse research and real-world applications,including studies and observation or forecasting of solid-Earth hazards,the dynamics of the atmosphere,climate,near-Earth space environment,and of key environmental parameters such as water storage,soil moisture,and seaand lake-level changes.UNAVCO operates facilities on behalf of the U.S.National Science Foundation to support investigators who use geodetic tools across all of these Earth and atmospheric domains.UNAVCO has built a number of large dense regional networks of GPS stations,including the Earth Scope Plate Boundary Observatory in North America,the COCONetCaribbean network,TLALOCNet in Mexico,GNET in Greenland,and ANET in Antarctica.Going forward,UNAVCO plans to federate the Plate Boundary Observatory(USA),TLALOCNet(Mexico),and COCONet(Caribbean)GPS networks as the Network of the Americas,with upgrades to state-of-the-art,multi-sensor,multi-GNSS observations.While UNAVCO community scientists actively engage in using space and terrestrial geodetic techniques to study geodynamics at all scales,this proliferation of continuous networks is the basis for a suite of recent contributions that focus on improved daily positioning to sense Earth’s elastic response and other perturbations to loading by atmospheric and surface water,oceans,and ice.Day-to-day and sub-daily variations in the GPS vertical and horizontal correlate to increasingly well-understood short-term mass variability,such as monsoonal flooding in Bangladesh,sub-daily changes in tidal loading at continent scales,day-to-day surface water and ice storage in the western U.S.,variations in the rate of GIA in Greenland across a variety of scales,and improved understanding of the inter-annual variation in sea level rise due to changes in terrestrial water storage.展开更多
Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination...Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination between Geodesy and Geodynamics,deepen the application of Geodesy in the field of Geoscience and quicken worldwide fellows’understanding on scientific research activity in China.It mainly publishes展开更多
Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination...Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination between Geodesy and Geodynamics,deepen the application of Geodesy in the field of Geoscience and quicken worldwide fellows’understanding on scientific research activity in China.It mainly publishes newest research achievements in the field of Geodesy,Geodynamics,Science of Disaster and so on.展开更多
Aims:The Journal of Geodesy and Geoinformation Science is an official publication of the Chinese Society for Geodesy,Photogrammetry and Cartography. The Journal aims to facilitate and strengthen academic exchange on g...Aims:The Journal of Geodesy and Geoinformation Science is an official publication of the Chinese Society for Geodesy,Photogrammetry and Cartography. The Journal aims to facilitate and strengthen academic exchange on geodesy and geoinformation research between China and other countries. Furthermore,it makes efforts to offer a forum for discussion between researchers in China and abroad.展开更多
A method is presented for determining instant values of Earth’s polar motion(PM)using a set of lunar laser ranging(LLR)measurements acquired simultaneously by tri-static common view(TCV)at three LLR stations in Europ...A method is presented for determining instant values of Earth’s polar motion(PM)using a set of lunar laser ranging(LLR)measurements acquired simultaneously by tri-static common view(TCV)at three LLR stations in Europe.We developed a model of the LLR TCV measurements,then formulated the linear equation for solving PM.Although there was no actual TCV event in the data,we conducted a two-phase study to test our method using actual LLR normal points(NPs)acquired by the European stations during 2012-2022.In the first phase,we simulated TCV events and PM solutions.The robustness of our method was assessed by introducing Universal Time(UT1)errors and per-station range errors in this phase.In the second phase,we augmented the actual LLR NPs with simulated data to generate realistic TCV events and solutions,using the‘1+2’and‘2+1’strategies,which differed in terms of data composition.Results indicated that a UT1 error of 0.1 ms caused PM errors of<18 mas,while a uniform range error of 50 mm resulted in PM errors of<180 mas.In the augmentation phase,the maximum solution errors were 752 and 899 mas,and 88.5% and 91.2% of the solutions were better than the predictions for the‘1+2’and‘2+1’strategies,respectively.The presented approach relies on precise geodetic data,and therefore,it is not intended to replace the traditional method.However,this study demonstrated that instant determination of PM is feasible and robust,although the accuracy requires further enhancement.展开更多
Spatio-temporal variation of sound speed,in seafloor geodetic precise positioning,can always be attributed to the time error.Firstly,this paper analyzes the existing error compensation model,i.e.,the time ratio model,...Spatio-temporal variation of sound speed,in seafloor geodetic precise positioning,can always be attributed to the time error.Firstly,this paper analyzes the existing error compensation model,i.e.,the time ratio model,which is expressed by the recorded time multiplying a ratio coefficient.And then a time split model is proposed by expressing the acoustic ray traveling time as the recorded time pluses a perturbation time error.The theoretical differences between the proposed time bias compensation model and the time ratio model are analyzed.Under the new framework,sound speed perturbation models with optimal single-layer spatial gradient and multi-layer spatial gradients are developed to compensate for sound speed error in the complex cases.Numerical computation shows that the simple time split model keeps the same accuracy as some complicated models while considering the distribution of random error.Furthermore,multi-layer model can improve the positioning accuracy without putting the pressure on parametrization.展开更多
基金funded by the National Key R&D Program of China(No.2020YFC150071)partly supported by the Shaanxi Province Geoscience Big Data and Geohazard Prevention Innovation Team(2022)and the Research Funds for the Interdisciplinary Projects,CHU(No.300104240914)。
文摘0 INTRODUCTION.According to the China Earthquake Networks Center,an M6.8 earthquake struck Dingri County,Xizang Autonomous Region,China,on 7 January 2025 at 9:05 a.m.local time.The epicenter is located at 28.5°N,87.45°E,with a depth of~10 km.
文摘The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,global warming,and the management of freshwater resources.It is also essential for the early warnings of hazards caused by ice avalanches.SAR imaging geodesy has been developed for measuring glacier velocity,especially the pixel-offset tracking method.This paper introduces some basic concepts of glaciology and principles of various SAR imaging geodesy methods,with a detailed presentation about the developments in the applications of the pixel-offset tracking method.Finally,the challenges and future prospects of SAR imaging geodesy in glacier monitoring are discussed.
基金National Natural Science Foundation of China(41931076)National Natural Science Foundation of China(41721003)。
文摘The geodesy discipline has been evolving and constantly intersecting and merging with other disciplines in the last 50 years,due to the continuous progress of geodetic observation techniques and expansion of application fields.This paper first introduces the development and roles of geodesy and its formation.Secondly,the development status of geodesy discipline is analyzed from the progress of observation techniques and cross-discipline formation is analyzed from the expansion of application fields.Furthermore,the development trend of geodesy is stated from the perspective of national requirements and scientific developments.Finally,the sub-disciplines for geodesy are suggested at the present stage,based on the requirements of the National Natural Science Foundation of China and development status of geodesy itself,which can provide references for topic selection and fund application of geodetic scientific research.
基金financially supported by the National Natural Science Foundation of China (Grant No.41174063)
文摘Modern geodetic techniques have developed rapidly in recent years, providing reliable observation data and new effective approaches, and greatly enhancing studies of the Tibetan geodynamics. For instance, the well-known GPS technique has been employed to measure seismic slips for many faults in the Tibetan Plateau. GPS data agree well with the hypothesis of a thickening crust and eastward mass flow. Moreover, absolute gravimetric data have been applied to interpret geophysical phenomena such as crust movement, co-seismic gravity change, GIA, and ground water change. The satellite gravity mission GRACE launched in 2002 provided global gravity models with unprecedentedly high precision and high spatial resolution. It has been used in implementing temporal gravity changes and improving our knowledge of the Earth＇s interior, including lithosphere dynamics, mantle viscosity and rheology, plateau uplift, and subduction processing. It is noteworthy that gravity presents unique advantages for the study of Tibetan geodynamics because of its sensitivity to mass migration and dynamic redistribution. To date, great advances have been made in applying modern geodetic data in studying dynamic changes of Tibetan plateau. For instance, the horizontal displacement field from GPS data revealed dynamical characteristics of the present-day Tibetan plateau. The combination of gravity anomalies and topographic data describe the tectonic characteristics of Tibetan plateau. The combination of gravity data and GPS data show present properties of the Tibetan plateau such as crust thickening, Moho＇s subsidence, and plateau uplift. GRACE data were used to estimate the distribution of ice/snow melting. These results demonstrate that mere application of integrated geodetic data as well as geophysical methods and numerical simulations can enhance our knowledge of Tibetan plateau dynamics. It must be pointed out that GRACE data include various geophysical signals such as crust vertical movement, denudation, ice and snow melting, GIA, ground water change, and permafrost degradation. To separate the tectonic information from other impulses, each physical signal must be evaluated and corrected carefully from the GRACE data. The Tibetan geodynamic problem is a complicated and synthetic issue that must be addressed through collaboration of workers in many fields. Succinctly put, although great achievements have been made in studying Tibetan plateau dynamics from each field, the dynamical process remains unclear. Some fundamental problems remain unresolved. They should be solved with modern geodetic data, such as GRACE, GPS, and absolute gravity data, combined with meteorological and geological data, for quantitative analysis of Tibetan plateau dynamics affected by respective geophysical sources. This review article introduces and discusses the scientific importance, advances, problems, and prospects of modern geodesy applied to the study of geodynamic changes of the Tibetan plateau.
基金financially supported by the National Natural Science Foundation of China (41574002)
文摘With the advanced development of the modern geodetic techniques, the geodetic obser- vations have been proved to be more powerful to uncover the geophysical phenomena, especially the seismic one, than that in the past time. The recent developments and achievements in the seismological geodesy are summarised here. Several popular geodetic techniques, such as high-rate GNSS, InSAR and Satellite Gravimetry, are introduced first to present their recent contributions in studying the seismic deformations. The developments of the joint inversion of the seismic source parameters from multiple observations are then highlighted. Some outlooks in seismological geodesy are presented in the end.
基金National Natural Science Foundation of China(No.41931076)Laoshan Laboratory(No.LSKJ202205105)+1 种基金National Key R&D Program of China(No.2020YFB0505802)State Key Laboratory of Geo-information Engineering(No.SKLGIE2020-M-1-1)。
文摘The ocean accounts for approximately 71%of the total area of the Earth.Whether it is studying the shape of the Earth itself through geodesy or the future development of earth system science,strengthening the construction of ocean geodesy disciplines and innovating ocean geodetic observation technologies have evident theoretical and practical significance.In recent years,the discipline of ocean geodesy in China has been continuously developing and growing,and notable breakthroughs have been made in ocean satellite geodesy and seafloor geodetic observation technology.Research on ocean geodetic observation models and algorithms has also made great progress.
基金supported by the NSFC projects(Grant Nos:41431069,41574002and 41721003).
文摘To overcome the high cost of learning,non-visual operation,and cumbersome steps of fine-tuning map elements in Generic Mapping Tools(GMT)and other geoscience mapping softwares,we present the Tectonic Geodesy Application(TGA),a user-friendly 64-bit tectonic geodesy mapping software based on the secondary development interface of the open source geographic information system QGIS.In this paper,we detailly introduce the architecture and function modules of our software,and highlight the functions of rendering and map decoration through four cases:the geologic map of Papua New Guinea,the seismicity in China and surrounding regions,the seismicity and crustal deformation of the Tibetan Plateau and the coseismic deformation of the 2017 Jiuzhaigou earthquake in China.Compared with GMT,the tectonic geodesy mapping software we developed has the advantages of simple operation,low learning cost and user-friendly interface.
基金State Key Basic Research Development and Programming Project (G1998040703) the Major Project for Basic Re-search of the Chinese Academy of Sciences (KJ951-1-304) and the Scientific and Technical Development Foundation of Shanghai (JC14012).
文摘The convergent and divergent velocities of active plate boundaries in the North Hemisphere are obtained with space geodetic data. The relative motions of adjacent plates in north-south direction are almost convergent; the spreading rates of the north mid-Atlantic ridge are smaller than the south mid-Atlantic ridge; the closed differences of the baseline length rates between stations on different plates along the latitudinal circle of 7.7, 23.3? 34.8? 42.0?and 51.0?are all negative. All these show that the North Hemisphere is a compressive hemisphere.
文摘Research of the practical 4-D integrated geodesy(IG) and strain analysis is presented in this paper.The practical model and basic observation equation are established by using IG and dynamic adjustment.Furthermore,the observation equations about gravity vector,zenith distance,azimuth angle,difference are derived and determination of local gravity field covariance solved.The 3-D strain formular is derived and the strain parameters calculated from it.The improvement of the OPERA software of Landan and Hem etc,FRG has been done to get a new software in Fortran Language which implements in MASSCOMP computer.Using the software,the integrated adjustment of two term observation data of triangle chain, triangle net,gravity,level,astronomic observation and strain analysis are established.The result is satisfactory.
基金Supported bythe National Natural Science Foundation of China （No.40637034, No. 40574004）, the National 863 Program of China （No. 2006AA12Z211）.
文摘The fictitious compress recovery approach is introduced, which could be applied to the establishment of the Rungerarup theorem, the determination of the Bjerhammar＇s fictitious gravity anomaly, the solution of the ＂downward con- tinuation＂ problem of the gravity field, the confirmation of the convergence of the spherical harmonic expansion series of the Earth＇s potential field, and the gravity field determination in three cases： gravitational potential case, gravitation case, and gravitational gradient case. Several tests using simulation experiments show that the fictitious compress recovery approach shows promise in physical geodesy applications.
文摘"Beyond 100: The next century in Earth and Space Science"The 27th IUGG General Assembly will be held July 8-18,2019 at the Palais des Congrès in Montréal,Québec,Canada.This is a special opportunity for participants from Canada and from around the world to come together and share their science and culture.2019 marks the 100th anniversary of IUGG;we will look back on the accomplishments of the previous century of Earth and space science research,and forward to the next century of scientific advancement.Join us for a host of scientific activities,including special public lectures,keynote Union lectures and a wide variety of themed sessions.
文摘UNAVCO supports geoscience research at 113 US academic Member institutions,and another 104 Associate Member institutions include international universities,laboratories,observatories,academies of science,and a museum.This diverse membership shares UNAVCO’s purpose at home and abroad,giving UNAVCO global reach in advancing geodesy.Since the mid-1980s,modern geodesy has evolved into a cutting-edge,multi-faceted toolbox with remarkably diverse research and real-world applications,including studies and observation or forecasting of solid-Earth hazards,the dynamics of the atmosphere,climate,near-Earth space environment,and of key environmental parameters such as water storage,soil moisture,and seaand lake-level changes.UNAVCO operates facilities on behalf of the U.S.National Science Foundation to support investigators who use geodetic tools across all of these Earth and atmospheric domains.UNAVCO has built a number of large dense regional networks of GPS stations,including the Earth Scope Plate Boundary Observatory in North America,the COCONetCaribbean network,TLALOCNet in Mexico,GNET in Greenland,and ANET in Antarctica.Going forward,UNAVCO plans to federate the Plate Boundary Observatory(USA),TLALOCNet(Mexico),and COCONet(Caribbean)GPS networks as the Network of the Americas,with upgrades to state-of-the-art,multi-sensor,multi-GNSS observations.While UNAVCO community scientists actively engage in using space and terrestrial geodetic techniques to study geodynamics at all scales,this proliferation of continuous networks is the basis for a suite of recent contributions that focus on improved daily positioning to sense Earth’s elastic response and other perturbations to loading by atmospheric and surface water,oceans,and ice.Day-to-day and sub-daily variations in the GPS vertical and horizontal correlate to increasingly well-understood short-term mass variability,such as monsoonal flooding in Bangladesh,sub-daily changes in tidal loading at continent scales,day-to-day surface water and ice storage in the western U.S.,variations in the rate of GIA in Greenland across a variety of scales,and improved understanding of the inter-annual variation in sea level rise due to changes in terrestrial water storage.
文摘Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination between Geodesy and Geodynamics,deepen the application of Geodesy in the field of Geoscience and quicken worldwide fellows’understanding on scientific research activity in China.It mainly publishes
文摘Aims and Scope Geodesy and Geodynamics is committed to the publication of quality scientific papers in English in the fields of Geodesy and Geodynamics from authors around the world.Its aim is to promote a combination between Geodesy and Geodynamics,deepen the application of Geodesy in the field of Geoscience and quicken worldwide fellows’understanding on scientific research activity in China.It mainly publishes newest research achievements in the field of Geodesy,Geodynamics,Science of Disaster and so on.
文摘Aims:The Journal of Geodesy and Geoinformation Science is an official publication of the Chinese Society for Geodesy,Photogrammetry and Cartography. The Journal aims to facilitate and strengthen academic exchange on geodesy and geoinformation research between China and other countries. Furthermore,it makes efforts to offer a forum for discussion between researchers in China and abroad.
基金supported by the National Natural Science Foundation of China(NSFC)(11673082 and 11903059).
文摘A method is presented for determining instant values of Earth’s polar motion(PM)using a set of lunar laser ranging(LLR)measurements acquired simultaneously by tri-static common view(TCV)at three LLR stations in Europe.We developed a model of the LLR TCV measurements,then formulated the linear equation for solving PM.Although there was no actual TCV event in the data,we conducted a two-phase study to test our method using actual LLR normal points(NPs)acquired by the European stations during 2012-2022.In the first phase,we simulated TCV events and PM solutions.The robustness of our method was assessed by introducing Universal Time(UT1)errors and per-station range errors in this phase.In the second phase,we augmented the actual LLR NPs with simulated data to generate realistic TCV events and solutions,using the‘1+2’and‘2+1’strategies,which differed in terms of data composition.Results indicated that a UT1 error of 0.1 ms caused PM errors of<18 mas,while a uniform range error of 50 mm resulted in PM errors of<180 mas.In the augmentation phase,the maximum solution errors were 752 and 899 mas,and 88.5% and 91.2% of the solutions were better than the predictions for the‘1+2’and‘2+1’strategies,respectively.The presented approach relies on precise geodetic data,and therefore,it is not intended to replace the traditional method.However,this study demonstrated that instant determination of PM is feasible and robust,although the accuracy requires further enhancement.
基金The National Natural Science Foundation of China under contract No.41931076the National Center for Basic Sciences Project under contract No.42388102the Laoshan Laboratory under contract No.LSKJ202205100.
文摘Spatio-temporal variation of sound speed,in seafloor geodetic precise positioning,can always be attributed to the time error.Firstly,this paper analyzes the existing error compensation model,i.e.,the time ratio model,which is expressed by the recorded time multiplying a ratio coefficient.And then a time split model is proposed by expressing the acoustic ray traveling time as the recorded time pluses a perturbation time error.The theoretical differences between the proposed time bias compensation model and the time ratio model are analyzed.Under the new framework,sound speed perturbation models with optimal single-layer spatial gradient and multi-layer spatial gradients are developed to compensate for sound speed error in the complex cases.Numerical computation shows that the simple time split model keeps the same accuracy as some complicated models while considering the distribution of random error.Furthermore,multi-layer model can improve the positioning accuracy without putting the pressure on parametrization.
