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Abstract
Evaluation of the mean climate and climate variability in the Southern Hemisphere (SH) in the Twentieth Century Reanalysis data version 2 (20CRv2) is conducted and the results are compared with the NCEP/ NCAR version 2 Reanalysis data (NCEPv2) and the Hadley Center sea-level pressure data (HadSLPv2). The results show that SH polar High, SH subtropical High, upper level split jet, cross-equatorial flow, Antarctic Oscillation (AAO), and the pattern of Pacific-South-America (PSA) has been effectively captured by 20CRv2 during 1979-2010, with an apparent zonal asymmetry of AAO in the austral winter (June-July-August, JJA). The notable upward linear trend of AAO in the entire period of 1871- 2010 is represented in both 20CRv2 and HadSlPv2. The most remarkable discrepancy of the SH climate variability between 20CRv2 and HadSLPv2 occurred in 1897-1920 and was partly caused by such factors as the paucity of meteorological and oceanographic data in the SH to be assimilated, the handling of the specified sea-ice concentration in South Pole, and imperfect climate models. The consistency of these reanalysis data is increased with the use of a large amount of satellite observation and radiosonde data, particularly after 1979.