Simulation Of Winter Teleconnection Patterns At 500hpa By BCC_AGCM2.1

Based on the model results and the NCEP/NCAR reanalysis data,the performance of Beijing Climate Center(BCC)atmospheric general circulation model version 2.1(BCC_AGCM2.1)is evaluated in reproducing winter climatology over East Asia.The ability of the model to simulate the mid-high latitude atmospheric teleconnection patterns and their relationships with the temperature and precipitation in China are also evaluated,which are Pacific/North American Pattern(PNA),Eurasian Pattern(EU),West Pacific Pattern(WP),West Atlantic Pattern(WA),and East Atlantic Pattern(EA).The major conclusions are as follows:The BCC AGCM2.1 model has good performance in reproducing the winter mean atmospheric general circulation over East Asia.Major components of East Asian winter monsoon system are well simulated.The spatial correlation coefficients are significantly high,which are over 0.9.The model can reproduce the main spatial structures of the 500hPa teleconnections during winter.The simulation skills are higher for WP and PNA.The ability to simulate the interannual variabilities of the 5 teleconnections is not very well,except that PNA and WP are relatively better.In terms of the teleconnection intensities,the strong and weak years of the 5 teleconnections are selected.It is found that the model can reproduce the interannual variability of the teleconnection indices,but there are some deficiencies in simulating the teleconnection intensities,especially for the strong or weak telconnection indices.The intensities of simulated teleconnection patterns are weak for the strong teleconnection years.The ability of the model to simulate the relationship between EU index and winter temperature and precipitation in China is poor,the model cannot better reproduce the negative correlation between EU index and winter temperature and precipitation in China.The simulation of the relationship between WP index and winter temperature and precipitation in China performs well.Relatively speaking,the ability to simulate the relationship between teleconnection indices and precipitation is better than that between teleconnection indices and temperature.