Influences of the Snow Cover Anomaly During Winter in Mid-latitude Region of East Asia on the Circulations of Early Summer

The influences of the snow cover anomaly during the winter in the mid-latitude region of East Asia on the variations of the dominant low frequency modes with seasons of the Eastern Hemisphere in early summer are studied based on the data from 1973 to 1994, and the differences of the intensity of 30~50 days low frequency oscillation over extratropical Eastern Hemisphere and the summer rainfall over China in snowy and less snowy years are discussed. The interannual variations of winter snow cover at mid-latitude in East Asia appear linear increasing and to have the quasi-biennial oscillation superimposed, and the relationships between its variation and the evolutions of the dominant low frequency modes are linear or nonlinear correlation at the same time. The intensities of low frequency oscillation are stronger for the most regions of Eurasian continents, but weaker in northeastern Asia in snowy years.