The reliability of the daily quick look solar wind velocities as indicators of interplanetary activity

It is shown that the daily quick look solar wind velocities based on the Ames Research Center solar wind plasma data obtained on the Pioneer spacecraft are surprisingly reliable indicators of interplanetary activity. These velocities, which are published in the monthly Solar Geophysical Data by NOAA, can appropriately be used in correlation studies with an average accuracy of ±5%. This accuracy reflects the ‘jitter’ in the solar wind velocity during quiescent intervals and across high-speed streams.