Evolution of Eurasian teleconnection pattern and its relationship to climate anomalies in China

The Eurasian teleconnection pattern (EU) is a major mode of low-frequency variability in the Northern Hemisphere winter, with notable impacts on the temperature and precipitation anomalies in Eurasia region. To investigate the structure, life cycle and dynamical mechanisms of EU pattern, diagnostic analyses are conducted to clarify EU pattern evolution, with an emphasis on EU development and decay. In the developing stage, a geopotential height anomaly over North Atlantic emerges 6 days before EU peak phase and other three geopotential height anomalies appear one by one in the following days. During this period, all geopotential height anomalies experience considerable growth and the four-center structure of EU pattern forms 2 days before peak phase. The obvious wave train structure appears at 300 hPa. The EU pattern growth is driven by both relative vorticity advection and transient eddy fluxes. After the peak phase, the geopotential height anomaly over North Atlantic becomes weak as it decays earlier than other anomaly centers, which leads to the classic three-center structure of EU teleconnection pattern. The complete life cycle of EU pattern experience considerable growth and decay within 10 days. During the decaying stage, the horizontal divergence and the transient eddy fluxes play important roles. Additionally, the relationship of EU pattern to winter climate anomalies in China is also analyzed focusing on the decaying stage. The impact of EU pattern on temperature and precipitation in China are significant in 2-4 days after EU peak phase and the distribution of temperature and precipitation anomaly has obvious regional differences.