RETRIEVAL OF EAST-WEST WIND IN THE EQUATORIAL ELECTROJET FROM THE LOCAL WIND-GENERATED ELECTRIC-FIELD

The paper presents a method to retrieve the height-varying east-west w ind U(z) in the equatorial electrojet from the local wind generated el ectric field E(w)(z), or from the radar-measured phase velocity v(p)(I I)(z) Of the type II plasma waves. The method is found to be satisfact ory when E(w) >> E(p), where E(p) is the vertical polarization electri c field generated by the global scale east-west electric field, E(y), and E(y) < 0.2 mV m(-1). Measurements of V-p(II) by a VHF backscatter radar can be inverted to obtain the causative wind profile by this met hod. The method is tested using a simulation study in which E(w)(z) an d V-p(II)(z) as generated by two different wind models are used. The r etrieved winds are compared with the original wind profiles and it is found that the error in the retrieved winds is mostly under 5%, for th e case of no errors in the model Pedersen conductivity (sigma(1)) prof ile and the E(w)(z) or V-p(II)(z) profiles used in the inversion. Even with a +/-20% error in the above profiles, the errors in the retrieve d winds are found to be less than 20% over 75% of the altitude range a nd 20-30% for the remaining 25% of the altitude range, on the average.