Abstract
Results of measurements of the negative ion density and its ratio to the positive ion density in the lower ionosphere (D-layer) of the polar region (Andøya) are presented. A comparison is made with previous data in mid-latitude region (KSC), which were obtained by a same instrument. It has been found that the negative ion-dominant region in the D-layer is compressed toward lower altitudes in the polar region than that in the mid-latitude by about 16 km. Some mechanisms for this and its relation to the ozone distribution are discussed.
