The pole tide and its effect on GRACE time‐variable gravity measurements: Implications for estimates of surface mass variations

• DOI: 10.1002/2015jb011986
• Publication Date: 2015-05-27T14:08:30Z
• Authors: John Wahr; R. Steven Nerem; Srinivas V. Betta...
• Keywords: Polar motion; Gravity of Earth; Solid earth; Surface gravity; Ocean tide

Abstract Gravity Recovery and Climate Experiment (GRACE) provides monthly solutions for the Earth's gravity field in form of spherical harmonic coefficients. These can be used to infer changes mass at surface. The pole tide (the response Earth oceans polar motion) causes signals dominated by harmonics degree 2, order 1. If is not removed from GRACE data, it affects coefficients those ( C 21 , S ) introduces errors when using determine surface variations. partially processing centers before solving field. But long‐period are usually included correction, so still present We discuss this issue standpoint somebody who uses fields mass. arrive a recommendation an optimal correction. describe how modify provided centers, that they conform with our recommendation. size contributions compared direct load‐induced contributions. As example, we show incompletely impact results trend ocean consider mantle anelasticity on corrections conclude unlikely affect more than 20%.