Simultaneous measurements of type-2 echoes in the equatorial electrojet (EEJ) and the 150 km echoes were made with a tri-beam radar on Pohnpei (Federated States of Micronesia). Using the mean Doppler velocity ([V-D]) to estimate the line-of-sight component of electron drift velocity ( (V) over right arrow (e)), we show that its vertical component (V-ez) increases with altitude and exceeds V-ez measured at 150 km, between 96 and 103 km. At 103 km, the ratio of vertical [V-D] to V-ez at 150 km was five. This enhancement explains the hitherto puzzling east-west asymmetry in [V-D] of type-2 echoes. More importantly, we show how the enhanced V-ez appears to be associated with the discrepancy in the altitude of peak current density of the EEJ, between measurement and model. We discuss roles played by kilometer-scale irregularities and close by describing apparent effects by atmospheric gravity waves.
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