In this paper we examine the responses of a dynamic-thermodynamic sea-ice model adapted to Ross Sea, Antarctica to the atmospheric forcings on the synoptic-seasonal-interannual time scales. Both dynamic and thermodynamic forcings are considered separately and combined to examine their relative importance in terms of the model behavior on different time scales and possible nonlinear interactions between dynamic forcing and thermodynamic forcing. The results show that the model responses to a given idealized synoptic scale forcing are strongly seasonally dependent with preference to summer sea-ice regime. This implies that better atmospheric wind and temperature data are the key for reasonable sea-ice modeling, especially in
summer. Seasonal surface wind forcing has a characteristics of a semi-annual ocsillation, which is responsible for a semi-annual sea-ice extent variation superimposed on the major seasonal sea-ice cycle. A 10-year real time interannual variations of surface wind and air temperature are used to force the sea-ice model. The resultant sea-ice interannual variations are on the same order of magnitude and phase as occurred in the real world, and the interannual wind perturbation induced sea-ice varaitions are comparable to those induced by surface air temperature perturbations in magnitude, but
differ in phase with the temperature previaling ENSO time scale perturbations while the QBO-like perturbations dominate in the wind perturbations. The difference indicates the Ross Sea sea-ice regime and its interannual variations are mainly driven by the interaction of dynamic and thermodynamic atmospheric forcings. Further studies are needed to understand the causes of the different dominant time scales revealed in the interannual variations of the surface wind and air temperature fields.