East‐west and vertical spectral asymmetry associated with equatorial type I waves during strong electrojet conditions: 1. Pohnpei radar observations

[1] We have studied a particularly strong vertical type I event with the equatorial Pohnpei radar. During that event, which lasted several hours, we routinely obtained type I waves in radar beams pointed vertically as well as at 14.3 degrees east and west of vertical. This data set has allowed us to revisit the question of the equatorial electrojet east-west and up-down asymmetries. These asymmetries are known to favor downshifted waves during the daytime electrojet. In our study we have contrasted type I spectra obtained simultaneously in the east and west beams, in addition to analyzing upshifted and downshifted waves in the vertical beam data. We have found that when the echoes become particularly strong, both the east-west and up-down power asymmetries may not only vanish but can even reverse their signs. Furthermore, these tendencies occur simultaneously in the east-west and up-down asymmetries. Finally, we have noted that the power asymmetry is accompanied by an asymmetry in type I Doppler shifts, which is only clearly visible, however, when the overall echo power is weaker.