Siberian high
6.(4) There is close relation between Arctic Ocean oscillation(AO) and temperature of Northeast China. When AO index is low, sea level pressure near Icelan in winter is low, region of Siberian high reduce, the winter monsoon in East Asian comparatively weaken, the temperature of Northeast China in winter half year seem to obviously rise up.
7.Less sea ice in the Greenland and Bering Seas together with more sea ice in the Sea of Okhotsk,the east of Barents Sea,Kara Sea and Hudson Bay during winter coincides with weaker Siberian high,Aleutian low and East Asian monsoon,stronger westerly in East Asia,and warmer air temperature in most part of China;
8.Using the NCEP/ NCAR reanalysis dataset covering a 40-year period from January 1958 to December 1997, sea surface temperature (1950-1992). and monthly sea-ice concentration dataset for the period from 1953 to 1995, we investigate connections between winter Arctic Oscillation (AO) and Siberian high (SH), the East Asian winter monsoon (EAWM), and winter sea-ice extent in the Barents Sea.
9.Results also indicate that in strong(weak)EAWM years,both the Siberian high and the upper-level subtropical westerly jet are stronger(weaker),and the Aleutian low and the East Asia trough are deeper(shallower)than normal,thus favorable(unfavorable)for the dominance of more powerful northwesterly wind and lower temperature over the subtropical region of East Asia.
10.After the abrupt, the latent heat anomaly is negative in the Kuroshio Extension and positive in the northeast of the Pacific Ocean, the Siberian High and the Aleutian Low weaken, the north range of the East Asian Trough strengthen and the south range weaken, the ridge over the Ural mountain weaken, and so the prevalent wind is from south in the east of China and HETAO area, where the air temperature rises up.
