Two dominant modes of winter temperature variations over China and their relationships with large-scale circulations in CMIP5 models

In this paper, we analyze the two dominant modes of winter surface air temperature (SAT) variations over China and their relationships with large-scale circulation anomalies. We then examine the fidelities of 20 individual models participating in the Coupled Model Inter-comparison Project Phase 5 in reproducing these two perspectives. Results showed that the winter SAT variations over China are dominated by two modes, a homogeneous warming pattern and a tripole pattern with warm departure in Northwest and Northeast China and cold departure in central and southern China. Consistent with the previous studies which documented the variations of the two modes are associated with the Siberian high and Arctic Oscillation (AO) anomalies, respectively, it is newly found that the variation of Empirical Orthogonal Function 2 (EOF2) mode is associated with the Northwest Pacific south–north dipole sea surface temperature anomaly in addition to the AO anomaly. Through comparisons with the observations, we identified that eight models outperform the others in simulating the two dominant modes and their relationships with large-scale circulation anomalies. These high-performing models were then selected to project future winter SAT changes over China under the Representative Concentration Pathway 4.5 (RCP4.5) scenario. Based on the multi-model ensemble mean, a nationwide warming was projected relative to the present climatology (1970–1999), with the largest increase in the Tibetan Plateau of 1.45 ± 0.62 °C by the period 2010–2039 and 2.87 ± 0.82 °C by the period 2050–2079; followed by Northeast China, Northwest China, North China, East China, Southwest China, and, finally, Southeast China.