Improved Arctic Ocean Mass Variability Inferred from Time-Variable Gravity with Constraints and Dual Leakage Correction

Abstract

The ocean mass variability inferred from Gravity Recovery and Climate Experiment (GRACE) satellites mission is challenged by the stripes and the leakage across land-ocean boundary. The recently released GRACE mascons solutions are advanced by applying constraints that remove efficiently the stripes and dual leakage correction that restores the coastal ocean mass variability. Here we quantitatively evaluate the improvement in the Arctic Ocean mass variability by GRACE mascons. To do so, we compare the combination of GRACE solutions (including the mascons solutions and traditional spherical harmonic coefficients (SHCs) solutions) and the steric estimates against the altimeter observations. Our results suggest that mascons solutions produce stronger correlations compared to SHCs solutions, especially along the coastal zone, indicating the importance of the dual leakage correction. Stronger correlation is produced by the mascons over a small basin in the interior of the Arctic Ocean, suggesting that mascons solutions deliver better ocean mass variability than the SHCs solutions. Since the comparisons are carried out over two sub-basins, we conclude that mascons are able to provide better regional ocean mass variability that may have implications for regional sea level budget, in particular over the coastal zone.

Keywords:

• Dual leakage correction
• GRACE
• mascons
• ocean mass variation
• time-variable gravity

Acknowledgments

We are grateful to two anonymous reviewers who improved this manuscript greatly. We thank GRACE groups, DTU and Met Office Hadley Centre for providing free data.

Conflicts of interest

The authors declare no conflict of interest.

Additional information

Funding

This research was funded by the National Natural Science Foundation of China (Grant Nos. 41904081, 41731069, 41874032 and 41574013) and the National Key Research and Development Program of China (2016YFB0501701). Dapeng Mu is supported by China Postdoctoral Science Foundation (2018M640628), and State Key Laboratory of Geodesy and Earth's Dynamics (SKLGED2019-2-4-E).