Experiments with GRACE Global Mascon Solutions

Abstract:

Global mascon solutions of Earth’s time-variable surface mass distribution have been introduced in recent years as new products enabling geodetic studies of GRACE observations. One such product, developed at NASA Goddard Space Flight Center (GSFC), derives 1-degree equal-area mascons using spatial constraints in conjunction with regional boundaries to capture signal within appropriate regions and quantify a global solution. In this study, a rigorous statistical analysis is conducted seeking improvements to the spatial regularization methods employed in creating the constraints used by this product. Until now, these solutions have applied an exponential weighting model within regions and no correlation between differing regions in deriving mascon values. This work explores alternatives to this spatial regularization technique. A statistically driven study of additional regularization methods is conducted in an effort to extract more signal and reduce noise in the GSFC product. Additionally, alternative region definitions are explored to both assess their impact on the global solution and investigate regions that have not been specifically addressed by the product in previous studies. This report serves as a summary of initial findings by the study, analyzing potential improvements to the spatial regularization technique as well as multiple newly investigated regions. Mascon solutions utilizing these potential changes are presented in comparison to the current product, and impacts of these changes are quantified and illustrated. Future work to be investigated is presented based on these initial findings.