The tropical intraseasonal oscillation in a coupled ocean-atmosphere general circulation model

In this study we report the simulation of the intraseasonal oscillation of the tropical atmosphere (TIO) in the coupled model GIOTTO. The model produc es a zonal wave number one eastward propagating disturbance with a mean per iod of 42 days, which is in good agreement with the observed TIO periodicit y. The simulated TIG, however, seems to be influenced by errors in the mode l mean state. In particular, the errors in the sea surface temperature of t he tropical Pacific appear to have a significant impact on the oscillation, affecting its spatial distribution and producing an excess of TIO activity over the eastern Pacific. Despite of these shortcomings, the model seems t o be able to reproduce some of the air-sea interaction mechanisms which cha racterize the observed TIO.