Data assimilation aims to blend incomplete and inaccurate data with physics-based dynamical models. In the Earth's radiation belts, it is used to reconstruct electron phase space density, and it has become an increasingly important tool for validating our current understanding of radiation belt dynamics, identifying new physical processes, and predicting the near-Earth hazardous radiation environment.

The dataset presents the electron flux reconstructed by assimilating electron flux measurements of the following spacecraft into the 3D Versatile Electron Radiation Belt model (VERB; Shprits et al., 2008, Subbotin and Shprits, 2009):

1. Van Allen Probes Magnetic Electron Ion Spectrometer (MagEIS; Blake et al., 2013) and Relativistic Electron Proton Telescope (REPT; Baker et al., 2013), and

2. Geostationary Operational Environmental Satellites (GOES) Magnetospheric Electron Detector (MAGED; Hanser, 2011), and Energetic Proton, Electron, and Alpha Detector (EPEAD; Onsager et al., 1996, Hanser, 2011).

The method employs a split-operator Kalman filter (Shprits et al., 2013). The dataset contains electron flux for the period from 01 October 2012 00:00 UT to 01 October 2016 00:00 UT, organized in monthly files for selected values of electron energies (0.5 MeV, 1 MeV, and 2 MeV) and equatorial pitch angles (20 degree, 50 degree, and 70 degree).