Year-to-year variations in the Meiyu and Baiu frontal precipitation zones in the CMIP3 20th Century simulation

Features of year-to-year variations in the meiyu frontal rain zone (mfz,in 110°e-125°e) and the baiu frontal rain zone (bfz,in 125°e-140°e) in june over 20 years (1980-1999),obtained by 22 climate models from the 20th century climate in coupled models experiment (20c3m) of the world climate research programme's coupled model intercomparison project phase 3 (cmip3),were compared with the year-to-year variations in two observed precipitation datasets. year-to-year variations in the latitudes of and precipitation in the mfz and bfz produced by the models were examined. the mfz and bfz were clearly defined in every year in the observed precipitation data,but not in every simulation case. medians of the latitude and precipitation in the modeled zones also did not always coincide with observations. whereas several models showed large variation ranges in latitude and precipitation,a few other models had unrealistically small variation ranges. in addition,the mutual relations between year-to-year variations in latitude and precipitation in the modeled mfz and bfz were compared with the relations in the observational data. some models showed unrealistically high correlations between latitude and precipitation,whereas several other models showed unrealistically low correlation or opposite correlation compared to the observations. many of the models did not reproduce realistic year-to-year variations in mfz and bfz consistent with the observations. © 2012,meteorological society of japan.