Atmospheric de-aliasing is one of the most important background models for recovering Earth's temporal gravity field from gravity satellite missions.To meet the needs of China's gravimetric satellite platform,...Atmospheric de-aliasing is one of the most important background models for recovering Earth's temporal gravity field from gravity satellite missions.To meet the needs of China's gravimetric satellite platform,an independent atmospheric dealiasing model that relies on Chinese meteorological data needs to be developed.The release of CRA-40,as the firstgeneration Chinese atmospheric reanalysis,provides the opportunity.This study proposes a revised modeling method to calibrate CRA-40 and develops a new atmospheric de-aliasing model(HUST-CRA,2002-20).Intensive assessments are made between HUST-CRA and the latest official de-aliasing product of the international gravity satellite mission.The tidal components of the two products demonstrate high consistency,e.g.,the spatial correlation for the major tide S_1 is 0.96.The non-tidal components of the two products are also equivalent:(1)the temporal correlation of low-degree terms is higher than 0.97,except for the term of S22(0.93);(2)the spectral correlation of degree geoid height up to degree/order 100 is as high as 0.99;(3)the confidence interval of the spatial correlation(2002-20)is[0.971,0.995]at a confidence level of 95%;and(4)the difference in KBRR(K-band range rate)residuals is less than 0.08μm s^(-1),the difference in the derived temporal gravity field is less than 0.32 mm in terms of geoid height,and both are apparently beyond the ability of the current gravity satellite mission.This confirms that CRA-40 is of high quality and that the derived de-aliasing product,HUST-CRA,is accurate enough to be used in both Chinese and international gravity satellite missions.展开更多
The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that nee...The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that needs to be converted to orthometric height for engineering applications.Information on geoid height,which can be calculated using the global geopotential mode,is required to convert such GNSS observations into orthometric height.However,its accuracy is still insufficient for most engineering purposes.Therefore,a reliable geoid model is essential,especially in areas growing fast,e.g.,the central part of Java,Indonesia.In this study,we modeled the local geoid model in the central part of Java,Indonesia,using terrestrial-based gravity observations.The Stokes'formula with the second Helmert's condensation method under the Remove-Compute-Restore approach was implemented to model the geoid.The comparison between our best-performing geoid model and GNSS/leveling observations showed that the standard deviation of the geoid height differences was estimated to be 4.4 cm.This geoid result outperformed the commonly adopted global model of EGM2008 with the estimated standard deviation of geoid height differences of 10.7 cm.展开更多
基金financial support from the National Natural Science Foundation of China(Grant Nos.42274112 and 41804016)supported by Danmarks Frie Forskningsfond[https://doi.org/10.46540/2035-00247B]through the DANSk-LSM project and HPC Platform of Huazhong University of Science and Technology。
文摘Atmospheric de-aliasing is one of the most important background models for recovering Earth's temporal gravity field from gravity satellite missions.To meet the needs of China's gravimetric satellite platform,an independent atmospheric dealiasing model that relies on Chinese meteorological data needs to be developed.The release of CRA-40,as the firstgeneration Chinese atmospheric reanalysis,provides the opportunity.This study proposes a revised modeling method to calibrate CRA-40 and develops a new atmospheric de-aliasing model(HUST-CRA,2002-20).Intensive assessments are made between HUST-CRA and the latest official de-aliasing product of the international gravity satellite mission.The tidal components of the two products demonstrate high consistency,e.g.,the spatial correlation for the major tide S_1 is 0.96.The non-tidal components of the two products are also equivalent:(1)the temporal correlation of low-degree terms is higher than 0.97,except for the term of S22(0.93);(2)the spectral correlation of degree geoid height up to degree/order 100 is as high as 0.99;(3)the confidence interval of the spatial correlation(2002-20)is[0.971,0.995]at a confidence level of 95%;and(4)the difference in KBRR(K-band range rate)residuals is less than 0.08μm s^(-1),the difference in the derived temporal gravity field is less than 0.32 mm in terms of geoid height,and both are apparently beyond the ability of the current gravity satellite mission.This confirms that CRA-40 is of high quality and that the derived de-aliasing product,HUST-CRA,is accurate enough to be used in both Chinese and international gravity satellite missions.
文摘The Global Navigation Satellite System(GNSS)positioning method has been significantly developed in geodetic surveying.However,the height obtained through GNSS observations is given in a geodetic height system that needs to be converted to orthometric height for engineering applications.Information on geoid height,which can be calculated using the global geopotential mode,is required to convert such GNSS observations into orthometric height.However,its accuracy is still insufficient for most engineering purposes.Therefore,a reliable geoid model is essential,especially in areas growing fast,e.g.,the central part of Java,Indonesia.In this study,we modeled the local geoid model in the central part of Java,Indonesia,using terrestrial-based gravity observations.The Stokes'formula with the second Helmert's condensation method under the Remove-Compute-Restore approach was implemented to model the geoid.The comparison between our best-performing geoid model and GNSS/leveling observations showed that the standard deviation of the geoid height differences was estimated to be 4.4 cm.This geoid result outperformed the commonly adopted global model of EGM2008 with the estimated standard deviation of geoid height differences of 10.7 cm.
