Using observation data, Yuan et al. (2009) found a significantly positive partial correlation between Indian Ocean Dipole (IOD) and the Tibetan snow cover in early winter. In the pure positive IOD years with no co-occurrence of El Ni.ANqo, the negative geopotential height anomalies north of India are associated with warm and humid southwesterlies to enter Tibetan Plateau from the Bay of Bengal after rounding cyclonically and supply more moisture. This leads to more precipitation and more snow cover over the plateau. To understand origins of the circulation anomaly pattern, an AGCM called FrAM is used to perform sensitive experiments with various SSTA forcings. Results show that with the global SSTA forcing of pure positive IOD, FrAM is successful in simulating the observed circulation anomaly pattern with a similar amplitude. With the SSTA forcing only within the tropical Indian Ocean, the circulation pattern is similar to that of the global forcing experiment but the amplitude is about the half. Series of sensitivity experiments are conducted to determine how SSTA in other basins may influence the circulation pattern.