The new unconstrained GRACE monthly solution SWPU-GRACE2021 is recently developed with the dynamic approach. The reprocessed GRACE L1B RL03 data and de-aliasing product AOD1B RL06 are applied to compute SWPU-GRACE2021.
The arc length is variable according to the L1B data quality, but the maximum is no more than 24 hours. The bias vector and scale matrix of the GRACE Accelerometer observation ACC1B product are estimable parameters. The data covers the period from April 2002 to Mai 2017. Due to data quality problems, there are some data gaps between September 2016 and April 2017.