Recent observations of thermosphere mass density from satellites have revealed new features of the Equatorial Thermosphere Anomaly (ETA) which enable much more in-depth investigation of its characteristics and its coupling to the more research-established Equatorial Ionosphere Anomaly (EIA).Our recent study (Lei et al.,J.Geophys.Res.,2012) has revealed that the field-aligned ion drag mainly contributes to the ETA trough,but has little effect on the ETA crests.However,the formation of the ETA crests is attributed to plasma-neutral heating which has two peaks in the topside ionosphere aside the magnetic equator.This invited talk will highlight the simulated results from the thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (NCAR-TIMEGCM) to demonstrate the relative contributions of the non-migrating tides and geomagnetic field configuration on the longitudinal variations between the ETA and the EIA.Meanwhile,the different longitude/UT dependence between the ETA and the EIA associated with geomagnetic activity is also presented.