How Good are the OMNI data?

Numerous satellites are used to collect solar wind data, such as THEMIS, ACE, and WIND. These satellites are located at different distances between the Earth and the Sun, and hence these data lag with respect to each other. To investigate the consistency between the THEMIS B and OMNI data, we look for the time when the position of the THEMIS B satellite is very close to the Earth-Sun line. 70 12-hour events from the years 2013-2018 were selected when the THEMIS B satellite was close to the Earth-Sun line. A comprehensive study quantifying the probability of correlation between the two sets of data was carried out using the Z-component of the solar wind interplanetary magnetic field. Preliminary analysis before data gap removal suggests a correlation coefficient above 0.6 occurs only 57.75% of the time, indicating that OMNI data is oftentimes unreliable. A further breakdown of events by OMNI spacecraft ACE and WIND is provided to investigate the correlation for each satellite.