Global mass flux solutions from GRACE: A comparison of parameter estimation strategies—Mass concentrations versus Stokes coefficients

Abstract

[1] The differences between mass concentration (mascon) parameters and standard Stokes coefficient parameters in the recovery of gravity information from gravity recovery and climate experiment (GRACE) intersatellite K-band range rate data are investigated. First, mascons are decomposed into their Stokes coefficient representations to gauge the range of solutions available using each of the two types of parameters. Next, a direct comparison is made between two time series of unconstrained gravity solutions, one based on a set of global equal area mascon parameters (equivalent to 4°Â 4°at the equator), and the other based on standard Stokes coefficients with each time series using the same fundamental processing of the GRACE tracking data. It is shown that in unconstrained solutions, the type of gravity parameter being estimated does not qualitatively affect the estimated gravity field. It is also shown that many of the differences in mass flux derivations from GRACE gravity solutions arise from the type of smoothing being used and that the type of smoothing that can be embedded in mascon solutions has distinct advantages over postsolution smoothing. Finally, a 1 year time series based on global 2°equal area mascons estimated every 10 days is presented.

Antarctica, Greenland and Gulf of Alaska land-ice evolution from an iterated GRACE global mascon solution

“…The cost function of Eqn (5) suggests a major philosophical difference between this study and past studies, in that multiple iterations of GN are actually carried out. For instance, Rowlands and others (2010) and Sabaka and others (2010) carry out a single step of GN, in whichh 1 is zero in Eqn (5). In this study, the step k update, x kþ1 , which reflects h kþ1 , is fed back into the KBRR processing in order to carry out the next iteration.…”

Analysis of a GRACE global mascon solution for Gulf of Alaska glaciers

“…This new solution is a subset of the high-resolution global mascon solution developed by the Space Geodesy Laboratory at the NASA Goddard Space Flight Center (Luthcke and others, 2013). We label this solution 'v12' following the version history of mascon solutions described in the literature (Luthcke and others, 2006a(Luthcke and others, , 2008(Luthcke and others, , 2013Rowlands and others, 2010;Sabaka and others, 2010). Our goal is to compare temporal (annual to semi-annual) and spatial variations in the v12 solution with independent data sources to assess the accuracy of the local mass-balance signal.…”

Recent changes in terrestrial water storage in the Upper Nile Basin: an evaluation of commonly used gridded GRACE products

“…Additionally, NASA's new monthly gridded GRACE product, Mass Concentration blocks (i.e. Mascons), estimates terrestrial mass changes directly from inter-satellite acceleration measurements and can be used without further post-processing (Rowlands et al, 2010;Watkins et al, 2015). GRGS GRACE products are also spherical harmonic-based, available at a 10-day time step, and can also be used directly since gravity fields are stabilized during the processing of GRACE satellite data (Lemoine et al, 2007;Bruinsma et al, 2010).…”