A century long integration of a coupled global ocean-atmosphere
model displays strong decadal modulation in the relationship between regional and large-scale Asian monsoon indices. This behavior is consistent with several previous observational studies. The model climate, including low-frequency variability, also compares favorably with observations. Thus, we use the model to study controls on the decadal variability in the Asian monsoon. Preliminary results suggest the intriguing hypothesis that low-frequency monsoonal variablity may be a manifestation of a global-scale decadal mode. This mode appears to be rooted in the northern extratropics. Results of a rigorous investigation of this hypothesis and possible physical mechanisms involved will be presented.