Mass Flux Solution in the Tibetan Plateau Using Mascon Modeling

Tianyi Chen,Qiujie Chen,Yunzhong Shen

doi:10.3390/rs8050439

Tianyi Chen, Qiujie Chen + Show 1 more

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https://doi.org/10.3390/rs8050439

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Abstract

Mascon modeling is used in this paper to produce the mass flux solutions in the Tibetan Plateau. In the mascon modeling, the pseudo observations and their covariance matrices are derived from the GRACE monthly gravity field models. The sampling density of the pseudo observations is determined based on the eigenvalues of the covariance matrices. In the Tibetan Plateau, the sampling density of per 1.5° is the most appropriate among all choices. The mass flux variations from 2003 to 2014 are presented in this paper, which show large mass loss (about −15.5 Gt/year) in Tianshan, North India, and Eastern Himalaya, as well as strong positive signals (about 9 Gt/year) in the Inner Tibetan Plateau. After the glacier isostatic adjustment effects from Pau-5-AUT model are removed, the mass change rates in the Tibetan Plateau derived from CSR RL05, JPL RL05, GFZ RL05a, and Tongji-GRACE02 monthly models are −6.41 ± 4.74 Gt/year, −5.87 ± 4.88 Gt/year, −6.08 ± 4.65 Gt/year, and −11.50 ± 4.79 Gt/year, respectively, which indicate slight mass loss in this area. Our results confirm that mascon modeling is efficient in the recovery of time-variable gravity signals in the Tibetan Plateau.

Highlights

The GRACE (Gravity Recovery and Climate Experiment) satellites, launched on 17 March 2002, have accumulated more than 10 years of observations to recover the Earth’s gravity field in high spatial and temporal resolutions [1]
Our results confirm that mascon modeling is efficient in the recovery of time-variable gravity signals in the Tibetan Plateau
Forsberg and Reeh successfully applied the mascon solution in calculating the mass flux over the Greenland from the GRACE Stokes coefficients without using filtering techniques [14], which can reduce the loss of gravity signals

Summary

Introduction

The GRACE (Gravity Recovery and Climate Experiment) satellites, launched on 17 March 2002, have accumulated more than 10 years of observations to recover the Earth’s gravity field in high spatial and temporal resolutions [1]. The time-variable Earth’s gravity field solutions from satellite tracking data are expressed in terms of either Stokes coefficients or mascon parameters. The mascon parameters in terms of point masses [7,14,15], spherical caps [16] and finite surfaces of constant density [17,18,19,20,21] can be directly calculated from either the GRACE tracking data [7,16,17,18,19,20,21] or the Stokes coefficients of monthly gravity field models [14,15,22]. Forsberg and Reeh successfully applied the mascon solution in calculating the mass flux over the Greenland from the GRACE Stokes coefficients without using filtering techniques [14], which can reduce the loss of gravity signals.

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