The impact of error covariance matrix structure of GRACE's gravity solution on the mass flux estimates of Greenland ice sheet

Ran, Jiangjun1; Tangdamrongsub, Natthachet2; Wan, Xiaoyun3

2021

10.1016/j.asr.2020.01.012

ADVANCES IN SPACE RESEARCH   影响因子和分区

0273-1177

1879-1948

The error variance-covariance matrices of the monthly GRACE gravity field models are usually well-structured (e.g., order-leading) to contain the error information of the monthly gravity field models, and they are important information to further improve the accuracy of the estimated mass transportation by a post-processing scheme. Intensive studies have been performed to understand the impact of different approximations of the full error variance-covariance matrix on the mass estimates obtained with the conventional GRACE-post processing methods (e.g., the de-striping method). In this study, based on the variants of the mascon approach which treat monthly GRACE solutions as input, we consider four different structures to the error variance-covariance matrix, (i) full matrix, (ii) block diagonal matrix, (iii) diagonal matrix, and (iv) identity matrix, and examine their impact on the mass transport estimates in Greenland. Using both synthetic and real data, we analyze the results at four temporal scales: (i) the long-term decadal scale, (ii) the inter-annual scale, (iii) the seasonal scale, and (iv) the monthly scale. Based on the synthetic study, we find that for the recovery of the long-term trend, the application of the diagonal structure obtains the best estimates. This is caused by the amplification of the model error in the mascon approach when considering the full and block diagonal structures of error variance-covariance matrix, not due to any imperfection of them. Therefore, we emphasize that one should be aware of mascon model deficiency in the mascon approach. Furthermore, the best inter-annual, seasonal and monthly mass estimates are derived by considering the block diagonal and full structures. This is caused by the behavior of the bias and the unique parameterization error in the case of different structures. A similar finding is also presented in the real data case. Finally, our analysis denotes the necessity of releasing the block diagonal structure together with the official monthly gravity field model for the GRACE Follow-On mission, instead of releasing only the diagonal structure as done for the GRACE mission. (C) 2020 COSPAR. Published by Elsevier Ltd. All rights reserved.

Mascon Greenland ice sheet Mass balance Data weighting Error variance-covariance matrix

SCI ; EI

英语

第一

National Natural Science Foundation of China[41974094,41874004,41774094] ; Fundamental Research Funds for the Central Universities[2652018027]

Engineering ; Astronomy & Astrophysics ; Geology ; Meteorology & Atmospheric Sciences

Engineering, Aerospace ; Astronomy & Astrophysics ; Geosciences, Multidisciplinary ; Meteorology & Atmospheric Sciences

WOS:000600867300016

ELSEVIER SCI LTD

20203309036088

Gravitation ; Covariance matrix ; Glaciers ; Processing

Manufacturing:913.4 ; Mathematics:921 ; Gravitation, Relativity and String Theory:931.5

SPACE SCIENCE

Web of Science

1.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen 518055, Peoples R China
2.Univ Newcastle, Sch Engn, Callaghan, NSW 2308, Australia
3.China Univ Geosci Beijing, Sch Land Sci & Technol, Beijing, Peoples R China

Ran, Jiangjun,Tangdamrongsub, Natthachet,Wan, Xiaoyun. The impact of error covariance matrix structure of GRACE's gravity solution on the mass flux estimates of Greenland ice sheet[J]. ADVANCES IN SPACE RESEARCH,2021,67(1):163-178.

Ran, Jiangjun,Tangdamrongsub, Natthachet,&Wan, Xiaoyun.(2021).The impact of error covariance matrix structure of GRACE's gravity solution on the mass flux estimates of Greenland ice sheet.ADVANCES IN SPACE RESEARCH,67(1),163-178.

Ran, Jiangjun,et al."The impact of error covariance matrix structure of GRACE's gravity solution on the mass flux estimates of Greenland ice sheet".ADVANCES IN SPACE RESEARCH 67.1(2021):163-178.