| Spatial and temporal variability of precipitation are necessary information to help assess the mass balance of the Antarctic ice sheets and its contribution to global sea level change. In this study, atmospheric numerical simulation and dynamic retrieval method are used to assess variability of modern Antarctic precipitation.; First, the Polar MM5, a modified version of PSU/NCAR MM5, has been run over Antarctica for the period of January through December 1993 to verify its performance in simulating Antarctic atmospheric circulation. Given its good performance, the Polar MM5 has been run for July 1996–June 1999 to study Antarctic precipitation variability.; Second, Antarctic precipitation from 1979–99 has been retrieved by a vertical motion calculation using ECMWF analyses (ECT, 1985–1999) and reanalysis (ERA-15, 1979–1993). The dynamic retrieval method is successfully applied to retrieve Antarctic precipitation from 1979–1999 in this study. In comparison with predicted values from ERA-15, ECT, and NCEP DOE AMID Version 2 reanalysis (NCEP2, 1979–1999), dynamic retrieval calculations capture more mesoscale features of the precipitation distribution over Antarctica. In comparison with available ice core measurements, the interannual variability of Antarctic precipitation is well represented by the dynamic retrieval results. Also, drift snow effects on redistribution of surface accumulation over Antarctica are assessed with surface wind fields from Polar MM5 output.; Finally, the ENSO signal in modeled precipitation over the West Antarctic sector bounded by 75°–90°S, 120°W–180° and the South Atlantic sector bounded by 65°–75°S, 30°W–60°W is evaluated. It is found that the modeled precipitation is generally anti correlated with the Southern Oscillation Index (SOI) over the West Antarctic sector while it is positively correlated with the SOI over the South Atlantic sector. The correlation between the SOI and West Antarctic precipitation is found much more pronounced in 1990s than that in 1980s. It is also found that precipitation over the West Antarctic sector is consistently and strongly anti-correlated with the strength of polar front jet, which is found to be moderately modulated by the ENSO cycle. These findings and the implied mechanism by which ENSO modulates West Antarctic precipitation suggest that a consistent ENSO signal exists in the West Antarctic precipitation. |
