Global Bathymetry Model Predicted from Vertical Gravity Gradient Anomalies

Abstract

Abstract:

The response function between bathymetry and vertical gravity gradient anomalies is derived. A global bathymetry model was formed using vertical gravity gradient anomalies and ship soundings based on the response function. The latitude rang of the model is 75°S~70°N and the resolution is 1′×1′. Comparing to ship soundings, the accuracy of the model in South India Ocean and Northwest Pacific was evaluated. The result show that, in the discussed region, the accuracy of the model predicted in this paper is better than ETOPO1, GEBCO and DTU10, and in Northwest Pacific, the accuracy is slightly better than the latest V15.1 model from SIO, the accuracy in South India Ocean is consistent with V15.1. The influence of high order terms and crust isostasy were discussed. It found that both of the two factors have nearly no effect on the result and can be ignored. The predicted model was compared with the model formed using gravity anomalies too. The result shows that, in the wave length 100 to 200km, the vertical gravity gradient anomalies are preferred to gravity anomalies. In Northwest Pacific, comparing with V15.1, the accuracy of the predicted model is increased by about 29.5％ when these two kinds of data were combined. It indicates that a bathymetry model of higher accuracy can be formed combining gravity anomalies and vertical gravity gradient anomalies.

Key words: Vertical Gravity Gradient Anomalies, Gravity Anomalies, Bathymetry, Crust Isostasy, Response Function

CLC Number:

P229.1
P737

References

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