Tongji-Grace02s, a static unconstrained GRACE-only gravity field model up to degree and order 180 was developed by Tongji University under the sponsorship of National Natural Science Foundation of China (41474017). To derive Tongji-Grace02s, the modified short-arc approach which estimates errors of non-conservative acceleration and attitude observations was adopted, and the GRACE-only data (including orbits, range-rates, non-conservative accelerations and attitudes) over the period Jan. 2003 to Jul. 2016 were used. The quality of Tongji-Grace02s is remarkably better than Tongji-GRACE01. In computing Tongji-Grace02s, neither constraint nor regularization was applied.

Input Data:- GRACE RL02 L1B (JPL) data products: Jan. 2003 – Jul. 2016- AOD1B RL05 (GFZ) de-aliasing product

Calculation method:- modified short-arc approach- arc length: 2 hours

Force models: - can be found in Chen et al. 2015 (Chen, Q., Shen, Y., Zhang, X., Hsu, H., Chen, W., Ju, X., Lou, L., 2015. Monthly gravity field models derived from GRACE Level 1B data using a modified short-arc approach. Journal of Geophysical Research: Solid Earth, 120(3), 1804-1819. http://doi.org/10.1002/2014JB011470).