Mass Variations in Antarctica From GRACE and GRACE-FO

Abstract

Changes on the Earth’s surface causes changes in the gravity field. Through dedicated satellite gravity missions such as Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow On (GRACE-FO), this change can be measured. Mass redistribution on the surface of the Earth such as water movement causes these changes. GRACE and GRACE-FO are able to measure several different water cycle mass re-distributions. This thesis will look at the change in the cryosphere in the Antarctic. The cryosphere is highly connected to climate change and is both affected by rising temperatures and affects the global sea level.

The thesis will look at the almost 20-year time series of data from GRACE and GRACE-FO and examine the mass variations. Common errors and corrections will be explained and implemented. The SLR replacement for lower degrees of the GRACE and GRACE-FO solution, GIA modeling and correction, leakage appearance and corrections through a forward modeling method. There are two main ways to examine GRACE and GRACE-FO data: through spherical harmonic coefficients and through mass concentration blocks. Different approaches to computing a trend from the time series will be looked at and evaluated. The trends will be compared with literature and the different ways of achieving the trend. The mass loss in the Antarctic is computed to be -105 ± 31 Gt/year from the time period from March 2002 to November 2022. It would appear that trend is decelerating slightly for the last period of time examined.