Abstract: We analyze the impact of Antarctic sea ice oscillation anomalies on southern hemisphere precipitation pattern with Global atmospheric general circulation model NCAR/CAM3 and climatic diagnosis method, and conduct a preliminary study on the possible mechanism of action. Results show that there was significant response in precipitation to the Antarctic sea ice oscillation anomalies, with positive center over the Atlantic Ocean to the east of South America and negative center over the Pacific Ocean to the west of South America, and its spatial pattern was similar to the Antarctic sea ice oscillation. The results of numerical experiments indicate that sea ice oscillation anomalies can take great effect to the middle troposphere atmosphere by changing the surface heat flux which could drive the ascending branch of Ferrell circulation, strengthen or weaken the intensity of Ferrell circulation, and then make influence on the distribution of southern hemisphere precipitation. In the peripheral waters of Amundsen / Bellingshausen sea where sea ice is less than normal, upward heat flux would increase, which can make the ascending branch of Ferrell circulation abnormally strong. Accordingly, the meridional transport is enhanced and the descending branch is strengthened, this would restrain the formation of precipitation in middle-lower latitude areas. In the peripheral waters of Weddell sea where sea ice is more than normal, the responses of meridional transport and precipitation are almost the opposite. However, the response is much weaker at this longitude zone due to the land surface effect in West Antarctica Peninsula and South America.

Key words: Antarctic sea ice oscillation, Ferrel cell, Precipitation anomalies