▶ The East Asian summer monsoon (EASM) is one of the most important and active components of the global climate system (Ding 1994; Chang 2004; Chang et al. 2011). On the interannual time scale, it has been demonstrated by previous studies that variablilty of the EASM is influenced by many factors, such as Eurasian snow cover (Wu and Qian 2003; Wu and Kirtman 2007; Zhao et al. 2007; Wu et al. 2009a), western Pacific subtropical high (Chang et al. 2000; Lu 2002), El Nino-Southern Oscillation (ENSO) cycle (Wang et al. 2000; Wu et al. 2003; Huang et al. 2004l Chen et al. 2013), western Pacific warm pool (Nitta 1987; Huang and Li 1987; Huang and Sun 1992), Indian summer monsoon (Wu 2002), and spring Arctic sea ice concentration (Wu et al. 2009b)
▶ The East Asian monsoon features strong southerly winds and abundant rainfall in summer a strong northerly winds and little rainfall in winter. Strong southerly flow in summer brings a large amount of water vapor from the tropical western Pacific and the Indian Ocean to eastern China, Japan, and the Korean Peninsula, causing continuous and heavy rainfall in these regions (Tao and Chen 1987; ding 1994; Chang et al. 2000a; Chen et al. 2009).
▶ The interannual variability of EASM is affected by anomalous states of lower boundary condition such as sea surface (SST), snow cover/snow depth, and soil moisture (Charney and Shukla, 1981). Among them, the snow cover/snow depth may have an importan effect on the interannual variability of the monsoon because of its ability to alter the surface albedo and to regulate the soil moisture (Hahn and Shukla 1976; Barnett et al. 1989; Yasunari et al. 1991; Sankar-Rao et al. 1996; Kripalani et al. 2003).
Figure.1 Regression patterns of seasonal-mean 850-hPa winds in (a) DJF, (b) 1MAM, and (c) 1JJA with respect to EAWMI. The plus symbol, 1, stands for the season following winter. Shading indicates the 90% confidence level according to a two-tailed Student’s t test. (Chen et al. 2013)
▶ Chang, Chih-Pei. East Asian Monsoon. Vol. 2. World Scientific, 2004.
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▶ Chen, Shangfeng, Wen Chen, and Renguang Wu. "An interdecadal change in the relationship between boreal spring Arctic
Oscillation and the East Asian Summer Monsoon around the early 1970s." Journal of Climate 28.4 (2015): 1527-1542.
▶ Chen, Wen, Juan Feng, and Renguang Wu. "Roles of ENSO and PDO in the link of the East Asian winter monsoon to
the following summer monsoon."Journal of Climate 26.2 (2013): 622-635.
▶ Ding Yihui. Monsoons over china. Vol. 16. Springer Science & Business Media, 1994.
▶ Yim, So‐Young, et al. "Two distinct patterns of spring Eurasian snow cover anomaly and their impacts on the East Asian
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