Abstract
In this paper, we present a statistical validation of the DSCOVR solar
wind data in the operational space weather archive. The DSCOVR
observations of the interplanetary magnetic field (IMF), solar wind
velocity, density, and temperature were hourly averaged and compared to
measurements from NASA’s ACE and Wind spacecraft. Hourly
averages, in general, show good correlations between the satellites for
the IMF, solar wind velocity GSE vx-component,
and density. During the period covered by this study (spanning from late
July 2016, when DSCOVR went operational, to the end of 2020), the DSCOVR
products show no clear evidence of permanent degradation. However, for
plasma parameters there were periods of disagreement with ACE and
Wind. The correlation coefficients (Pearson’s r)
calculated over the entire study period were similar or the same between
DSCOVR versus Wind and DSCOVR versus ACE. For comparisons between
DSCOVR and Wind, the IMF Bx and
By GSE r were 0.94 and 0.96, respectively,
while r for the IMF GSE Bz-component was 0.88. For solar
wind velocity, r was found to be 0.96 for the GSE
vx-component, compared with 0.30 for
vy and 0.33 for vz. For
density, r was found to be 0.84. DSCOVR density observations tend
to overestimate compared to Wind values when the solar wind
densities are low (below ∼5 /cc), while agreement between the two
spacecraft on IMF measurements tend to increase with decreasing spatial
separation.