A dataset of GRACE intersatellite geopotential differences from April 2002 to July 2016

Abstract

Gravity Recovery and Climate Experiment (GRACE) satellite gravimetry can monitor surface mass variations with a spatial resolution of ~300km and a temporal resolution of 1 month. GRACE intersatellite geopotential difference (GPD) is a type of in-situ gravimetric observables with explicit geophysical interpretation, which can directly reflect surface mass variations. The intersatellite GPDs are estimated from GRACE Level-1B (RL03) data (including KBR range-rate measurements (KBR1B), satellite orbits (GNV1B), accelerometer measurements (ACC1B), and satellite attitude measurements (SCA1B)) based on an improved energy balance equation, and the orbit and background model errors are reduced using empirical parameters based on the remove-compute-restore (RCR) technique. Background models used for estimating GRACE intersatellite GPDs are consistent with GRACE Level-2 Processing Standards Document (for Level-2 Product RL06). GRACE intersatellite GPD data are processed over the period from April 2002 to July 2016 with a sampling rate of 5s along the satellite orbits (orbit height is ~450km), and stored on a monthly basis. There are total 155 months of data files over the period from April 2002 to July 2016, and the other 17 months of data are not available due to the instrument failure or other influencing factors. Each data file includes the positions of GRACE satellites A and B in Earth-centered Earth-fixed (ECEF) coordinate system, intersatellite geopotential differences after deducting the mean gravity field model GGM05C (i.e., the disturbance potential difference TAB=TB-TA), and the corresponding quality flags. GRACE intersatellite GPD data are validated through the estimation of monthly gravity field solutions and regional surface mass variations. The estimates inferred from GPD data are compared with GRACE official monthly solutions and mascon solutions, such as the products published by the Center for Space Research (CSR), Jet Propulsion Laboratory (JPL), German Research Center for Geosciences (GFZ), and Goddard Space Flight Center (GSFC). It is demonstrated that the differences between GPD-inferred results and the official released models are within the range of the differences among those official models.  GRACE intersatellite GPD dataset enriches the GRACE data products, and can be applied to directly invert the monthly gravity field models, global and regional surface mass variations, which is helpful to study the terrestrial water cycle, ice sheets and mountain glacier mass balance, sea level change, and ocean bottom pressure variations, etc.