Applicability of GRACE and GRACE-FO for monitoring water mass changes of the Aral Sea and the Caspian Sea

Lorant Földváry,Victor Statov,Nizamatdin Mamutov

doi:10.35595/2414-9179-2020-2-26-443-453

Lorant Földváry, Victor Statov + Show 1 more

Open Access

https://doi.org/10.35595/2414-9179-2020-2-26-443-453

Copy DOI

Abstract

The GRACE gravity satellite mission has provided monthly gravity field solutions for about 15 years enabling a unique opportunity to monitor large scale mass variation processes. By the end of the GRACE, the GRACE-FO mission was launched in order to continue the time series of monthly gravity fields. The two missions are similar in most aspects apart from the improved intersatellite range rate measurements, which is performed with lasers in addition to microwaves. An obvious demand for the geoscientific applications of the monthly gravity field models is to understand the consistency of the models provided by the two missions. This study provides a case-study related consistency investigation of GRACE and GRACE-FO monthly solutions for the Aral Sea region. As the closeness of the Caspian Sea may influence the monthly mass variations of the Aral Sea, it has also been involved in the investigations. According to the results, GRACE-FO models seem to continue the mass variations of the GRACE period properly, therefore their use jointly with GRACE is suggested. Based on the justified characteristics of the gravity anomaly by water volume variations in the case of the Aral Sea, GRACE models for the period March–June 2017 are suggested to be neglected. Though the correlation between water volume and monthly gravity field variations is convincing in the case of the Aral Sea, no such a correlation for the Caspian Sea could have been detected, which suggests to be the consequence of other mass varying processes, may be related to the seismicity of the Caspian Sea area.

Highlights

Geoinformatics, basically, a tool for handling geographic information, that is data and information having an implicit or explicit association with a location relative to the Earth4
This study provides a case-study related consistency investigation of GRACE and GRACE-FO monthly solutions for the Aral Sea region
GRACE-FO models seem to continue the mass variations of the GRACE period properly, their use jointly with GRACE is suggested

Summary

INTRODUCTION

Geoinformatics, basically, a tool for handling geographic information (or shortly geoinformation), that is data and information having an implicit or explicit association with a location relative to the Earth[4]. The GIS tools, which were applied in that study were: 1) representation of the data sets (both gridded and sparse data); 2) interpolation of one data to the points of the other; 3) outlier detection by comparison the interpolated data with the other; 4) smoothing of the outlier-eliminated data and interpolation back to the original points Even though they have concluded that GIS was fast and reliable, they have found that it may have a little, but meaningful impact on geodesy. Further attempts for gravity field GIS are provided by Hobbs et al [2000], Hinze et al [2005], Wang, Zhang [2008], Tracey, Nakamura [2010] and Földváry et al [2015] The latter has developed a GIS package termed Gravity_RS_GIS, which has used as input data for temporal gravity variation GRACE monthly solutions for the period of April 2002 to April 2015 [Földváry et al, 2015].

MATERIALS AND METHODS

X a d a

Findings

CONCLUSIONS