D-region electron density measurements by MF radar in the middle and high latitudes Original Research Article

The second MF radar was deployed at Wakkanai (45.36° N, 141.81° E) in September, 1996, in addition to the MF radar at Yamagawa (31.20° N, 130.62° E). The Wakkanai MF radar has a capability of electron density measurements in D-region. The differential absorption technique is applied in order to measure the electron density profile in the D-region regularly. Observations of both of wind and electron density are conducted every 2 minutes alternately at Wakkanai. Monthly variations of electron density profile in the D-region are presented and discussed by comparing with the IRI-95 model. Preliminary electron density profiles in the D-region obtained during the test operation of MF radar at Poker Flat (65.1° N, 147.5° W) are also compared with the IRI-95 model. Monthly mean variations of electron density profiles are discussed for Wakkanai and Poker Flat. Seasonal variations of electron density profile in the D-region are compared between northern and southern hemispheres using the IRI95 model.