Assessment of surface pressure between Zhongshan and Dome A in East Antarctica from different meteorological reanalyses

The accuracy of daily mean surface pressure from five meteorological reanalyses is assessed against in situ observations from automatic weather stations in East Antarctica for 2005 to 2008. The in situ observations are from Zhongshan, LGB69, EAGLE, and Dome A. The five reanalyses all explain more than 87% of the average variance and have annual root mean square errors between 15 hPa and 45 hPa. The ERA Interim reanalysis performs best against both criteria. The NCEP-1, NCEP-2, and 20CRv2 reanalyses have negative biases of 29.7 hPa, 25.9 hPa, and 11.1 hPa, respectively, while ERA Interim and JCDAS have positive biases of 4.9 hPa and 14.9 hPa. The reanalyses do not show obvious seasonal differences. The errors generally tend to decrease from the coast to the interior of the East Antarctic ice sheet, although there are regional differences between the performance of the different reanalyses. ERA Interim is superior to other reanalyses, probably because of its 4D assimilation scheme, which is strongly guided by satellite observations. The three NCEP reanalyses perform worst; their assimilation scheme is more constrained by limited observations and 20CRy2 has less input data, assimilating only surface pressure observations. Despite deficiencies and limitations, the reanalyses are still powerful tools for climate studies in the Antarctic region. However, more in situ observations are required, especially from the vast interior of Antarctica.