The fictitious compress recovery approach is introduced, which could be applied to the estab-lishment of the Runge-Krarup theorem, the determination of the Bjerhammar's fictitious gravity anomaly, the solution of ...The fictitious compress recovery approach is introduced, which could be applied to the estab-lishment of the Runge-Krarup theorem, the determination of the Bjerhammar's fictitious gravity anomaly, the solution of the "downward continuation" 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 ge-odesy applications.展开更多
Sea ice concentration (SIC) is an important parameter in characterizing sea ice. Limited by the environment and the spatial extent of observation, it is difficult for field work to meet the needs of a large-scale SIC ...Sea ice concentration (SIC) is an important parameter in characterizing sea ice. Limited by the environment and the spatial extent of observation, it is difficult for field work to meet the needs of a large-scale SIC study. However, with its many advantages, such as the ability to make large-scale, high-resolution and long-duration observations, the altimeter can be used to determine SIC on a large scale. Using the correspondence between the satellite pulse altimeter waveform and reflector property, waveform classification is employed. Moreover, this paper develops an algorithm to obtain the SIC from altimeter waveforms. In an actual computation, Pyrz Bay in the Antarctic is taken as an experimental region, and one-year and seasonal SICs are derived from ERS-1/GM waveforms over this study area. Furthermore, altimetric SICs are compared with those of SSMR SSM/I. The results show that the spatial distribution and the regions of maximum SIC determined employing these two methods are consistent. This demonstrates that altimeter data can be used to monitor sea ice.展开更多
The global tectonic change deduced from geophysical research was first identified by space geodetic data from VLBI, GPS and SLR measurements. whether using geodesic rates or using vertical velocities of stations, thre...The global tectonic change deduced from geophysical research was first identified by space geodetic data from VLBI, GPS and SLR measurements. whether using geodesic rates or using vertical velocities of stations, three kinds of data and their integration give consistent results: within the mid-latitude belt on the Northern Hemisphere there may be about 8 - 10 mm/a contracting change; within the mid-latitude belt on the Southern Hemisphere there may be about 12-14 mm/a expanding change. This result not only validates the reverse global tectonic change in the Southern and Northern Hemispheres of the Earth, but also gives relatively precise quantative estimations.展开更多
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 estab-lishment of the Runge-Krarup theorem, the determination of the Bjerhammar's fictitious gravity anomaly, the solution of the "downward continuation" 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 ge-odesy applications.
基金supported by National Key Technology R & D Program (Grant No. 2006BAB18B01)the National Natural Science Foundation of China (Grant No. 40806076)+2 种基金Antarctic Exploration Fundamental Project (Grant No. 14699907111091)Chinese Polar Strategic Research Foundation (Grant No. 20080203)Key Laboratory of Surveying and Mapping Technology on Island and Reef of the State Bureau of Surveying and Mapping (Grant No. 2009B04)
文摘Sea ice concentration (SIC) is an important parameter in characterizing sea ice. Limited by the environment and the spatial extent of observation, it is difficult for field work to meet the needs of a large-scale SIC study. However, with its many advantages, such as the ability to make large-scale, high-resolution and long-duration observations, the altimeter can be used to determine SIC on a large scale. Using the correspondence between the satellite pulse altimeter waveform and reflector property, waveform classification is employed. Moreover, this paper develops an algorithm to obtain the SIC from altimeter waveforms. In an actual computation, Pyrz Bay in the Antarctic is taken as an experimental region, and one-year and seasonal SICs are derived from ERS-1/GM waveforms over this study area. Furthermore, altimetric SICs are compared with those of SSMR SSM/I. The results show that the spatial distribution and the regions of maximum SIC determined employing these two methods are consistent. This demonstrates that altimeter data can be used to monitor sea ice.
文摘The global tectonic change deduced from geophysical research was first identified by space geodetic data from VLBI, GPS and SLR measurements. whether using geodesic rates or using vertical velocities of stations, three kinds of data and their integration give consistent results: within the mid-latitude belt on the Northern Hemisphere there may be about 8 - 10 mm/a contracting change; within the mid-latitude belt on the Southern Hemisphere there may be about 12-14 mm/a expanding change. This result not only validates the reverse global tectonic change in the Southern and Northern Hemispheres of the Earth, but also gives relatively precise quantative estimations.
