As an important component of the East Asian winter monsoon,the Siberian High(SH) can cause low temperatures,snowy weather and strong wind,which has a substantial influence on the winter climate of China.In order to mitigate the effects of the SH,it is important to study in depth the climate characteristics of the SH and its impact factors.Using NCEP/NCAR reanalysis monthly data and sea surface temperature(SST) data from NOAA and other data for the period 1951-2014,this study investigates the variational characteristics of the SH and SST in the North Atlantic,employing the methods of empirical orthogonal function(EOF) analysis,conventional synthesis analysis,Gaussian filtering,and the t-test of statistical significance.Moreover,their connection and its temporal and spatial changes are also revealed,based on correlation analysis and regression analysis.The results are as follows:(1) The intensity of the SH in winter changed from strong to weak in the mid to late 1960s,but enhanced slightly again after 2003.The SH expands outward significantly in strong anomaly periods,whereas it shrinks obviously in weak anomaly periods;and the swing amplitude of its east and north edge is bigger than that of the west and south edge.(2) The North Atlantic SST index(normalized anomaly value of the whole region's average SST) decreased in all seasons in the mid-1960s,but rose again from the late 1990s.The time in which the North Atlantic SST tripole converted from positive to negative phase came relatively later in the early 1970s(spring and winter) than in the early 1960s(summer and autumn),but then the tripole of all four seasons turned into a positive phase again in the mid-1990s.The phase variation of the North Atlantic SST tripole commonly induces the change of the North Atlantic SST index.(3) An anomalously high(low) North Atlantic SST index and positive(negative) phase of the North Atlantic SST tripole in all seasons can together make the winter SH strengthen(weaken).Furthermore,by comparison,the relationship between the former and the SH intensity is more outstanding,and their correlation gradually decreases to a minimum from spring to summer,meaning the period is the relationship conversion period,and then gradually increases to a maximum from autumn to winter.In all seasons the northern part and southwest part of the North Atlantic are both key regions having a positive impact on SH intensity.The SH's response range to the SST anomaly of the north part is widest in winter and smaller in summer and autumn;whereas for the SST anomaly of the southwest part,the SH's response range is maximum in summer and minimum in winter.(4) When the North Atlantic SST index is anomalously high in winter,the winter 500 hPa height above its northern waters is abnormally high owing to the heating of the underlying surface,and a Rossby wave train is excited in downstream Eurasia,making the Ural Mountains' high-pressure ridge enhance prominently,and resulting in a larger negative vorticity being delivered to the upper levels of the SH by the northwest airstream in front of the Urals ridge.As a result,negative relative vorticity advection over the SH increases and,along with the reinforcement of high-level convergence and low-level divergence,the downdraft in the whole troposphere also grows significantly.The above situation causes the enhancement of SH intensity,and vice versa.