Heterogeneous Gravity Data Fusion and Gravimetric Quasigeoid Computation in the Coastal Area of China

ABSTRACT

Different types of gravity observations are available over coastal areas. The main challenge for coastal geoid determination is the proper fusion of heterogeneous gravity data including land, shipborne, airborne, and altimetry-derived gravity data. This paper describes the gravity data fusion and the computation of the gravimetric quasigeoid in the coastal area of mainland China. An iterative procedure of the weighted least-squares prediction based on rectangular harmonic functions is used for merging the land, altimetric, shipborne, and airborne gravity data. Applying the analytical continuation method in Molodensky's theoretic frame, the merged gravity data are then used to determine the gravimetric quasigeoid model by using the generalized Stokes' integral in a remove-compute-restore fashion. The gravimetric quasigeoid model is compared with the height anomalies determined at 662 GPS leveling points over the coastal region of mainland China, where both the geodetic height and the normal height are known. The standard deviations of the differences in the coastal provinces range from 1.8 to 4.4 cm. For the entire computation area, the mean and standard deviation of the differences are 27.9 and 3.9 cm, respectively.

KEYWORDS:

• Coastal quasigeoid
• data fusion
• heterogeneous gravity

Acknowledgements

Ms. Xiali Wang is greatly appreciated for her constructive suggestions and discussions. We thank the three anonymous reviewers for their constructive comments and helpful suggestions.

Funding

This work is jointly funded by the National Natural Science Foundation of China (grant No. 41374081 and 41674024), the National High-Tech Research and Development Program of China (grant No. 2009AA121405), and the National Science and Technology Support Program of China (grant No. 2012BAB16B01).