Observations of equatorial spread-F from Haleakala, Hawaii

[1] Since the 1920s it has been known that the equatorial ionosphere can become highly disturbed in the post- sunset period. We have placed a new array of instruments on top of the Haleakala Volcano in Hawaii to study these disturbances from midlatitudes. Two airglow imagers provide two-dimensional snapshots of the development of these disturbances during the night, while two GPS receivers can quantify their severity. Here we report on the spectacular February 16- 17, 2002 disturbance, which reached an altitude of 1500 km over the magnetic equator and mapped magnetically to latitudes well north of Hawaii. The signals from every Global Positioning System satellite in the field of view from Maui were severely disturbed whenever the corresponding look direction passed through one of the turbulent features. We also present an example from March 19, 2002 in which the spread- F activity is not as severe to demonstrate that the instrumentation still provides valuable information.