Bathymetry Model in the Northwestern Pacific Ocean Predicted from Satellite Altimetric Vertical Gravity Gradient Anomalies and Ship-Board Depths

Abstract

New bathymetry models in the northwestern Pacific Ocean are presented at 1 arc-minute and 15 arc-second resolution. The latest version of the altimetric vertical gravity gradient (VGG) anomalies from Scripps Institute of Oceanography, ∼7 million single-beam depths from the National Centers for Environmental Information, and ∼80 GB of multibeam grids from the Japan Agency for Marine-Earth Science and Technology are used. The ship-board depths are used to constrain bathymetry at wavelengths longer than 200 km, and calibrate the local topography to VGG ratio at 15–200 km wavelength bands. The VGG is used to predict bathymetry at 15 ∼ 200 km wavelength bands. The spectrum analysis results show that the 1 arc-minute model has more power than models predicted from gravity anomalies at wavelengths shorter than 100 km. The standard deviation of differences between the 1 arc-minute model and ship-board depths is 44.76 m, and it is 102.842 m comparing to the SIO topo_20.1.nc model. The accuracy of the new 1 arc-minute model has been improved significantly from our last bathymetry model, BAT_VGG, and has a better accuracy than that of the DTU18, GEBCO_08, and ETOPO1 models. The accuracy of the 15 arc-second model is consistent with that of SRTM + V2.1 and GEBCO_2020.

Keywords:

• Altimetry
• bathymetry
• ship-board depths
• vertical gravity gradient anomalies

Acknowledgments

The Scripps Institute of Oceanography is acknowledged for providing the latest version of altimetric vertical gravity gradient anomalies (curv_30.1.nc). The National Centers for Environmental Information is acknowledged for providing ∼7 million single-beam depths. The Japan Agency for Marine-Earth Science and Technology is acknowledged for providing ∼80 GB of multibeam grids. The GMT6.1.1 was used to manipulate some datasets and produce figures in this paper (Wessel et al. 2019).

Discosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, Minzhang Hu.

Additional information

Funding

This work was supported financially by the National Key Research and Development Project of China (no. 2017YFC1500403-03) and Nature Science Foundation of China (No. 41504017).