Effects on the low-latitudinal ionospheric structure of the lower atmosphere dynamics and magnetospheric electric field as produced by the C-IAM

A newly developed Canadian Ionosphere and Atmosphere Model (C-IAM) is introduced. The model extends from the surface to the inner magnetosphere and hence, is able to describe in a self-consistent way the impact of the lower atmosphere variability on the ionosphere. The C-IAM has been used to investigate forming of the 4-peak longitudinal structure of the 135.6 nm ionospheric emission observed over the tropics. As produced by the C-IAM, this structure is in a good agreement with the observations. The main mechanism for generating this structure is a modification of the ionospheric dynamo field caused by longitudinal variation of the zonal wind due to waves penetrating from the lower atmosphere. However, during geomagnetic storms and substorms (K_p > 5) the high-latitudinal electric field fully suppresses the dynamo, so that the emission intensity dramatically decreases and the 4-peak structure does not appear.