The initial surface and subsurface temperature fields are important for ENSO prediction due to the oceans long memory.As a result, most ENS0 predictions are initialized by ocean data assimilation.However another key for the development of an ENS0 event is the wind anomalies in the western Pacific associated with air-sea coupled tropical convection systems.Therefore the assimilation of both atmospheric and oceanic observations should be taken into account for ENSO prediction.However one difficulty is that the atmosphere has relative short memory on its initial conditions.This can be even worse if one uses the intermediate coupled models in which the atmospheric components are statistical and slavery to ocean components.