The Possible Effect Of Anomalous Arctic Sea SIC On Summer Climate Of China

The feedback of Arctic SIC on atmosphere is revealed on the warming or cooling of SIC. Short term of the external force can result in the contribution of spring SIC to seasonal effect on summer rainfall , while, autumn and winter SIC not, but forecast. We perform statistic analysis and model tests to study impact of Arctic SIC.The relations between SIC in each season and the climate of summer are researched by SVD, and aim to search the most meaningful mode. Variations on spring SIC can lead to Eurasian waves in Z500, and evolved from spring to summer. The negative center moved to North Europe and East Asia from Southwest Europe and the Urals, and the positive moved to Kara Sea from North Europe. The special pattern of SLP are same as Z500, then contribute to more rainfall in Northeast and Central China, and less in South China. Since blocking high in summer can affect rainfall evidently, we focus on the leading mode and blocking mode of climatic fields.The leading SVD of autumn SIC revealing less SIC in Arctic Oceans correspond to high on North Europe and Northeast Asia , low on Urals in Z500, less rainfall in North China and more in Central and South China, while ,the third mode showing less SIC on West of 60 degrees and more East of, leads to blockings in Urals and Okhotsk Sea in Z500 and more rainfalls in East of bend of Yellow River and Central South China, and less in other regions.While, the leading SVD between winter SIC and Z500 revealing more SIC in Kara Sea correspond to teleconnection with centers on North Europe,Kara Sea,Northeast China, and more rainfall in South China, less in Northeast China and band of Yellow River, while, the third mode showing similar blockings as autumn SIC analysis, with more rainfall in North China,South of Yangtse River, less in South China. However, we cannot find the similar blocking in SVD between winter SIC and Rainfall of summer, and contribute to less rainfall in Central China, which is opposite to previous SVD.The influence of Arctic Sea SIC Concentration(SIC) anomalies on the atmospheric general circulation during spring and summer is investigated with version 3.0 of the NCAR Community Atmosphere Model. Regress the second EOF of SIC to observed SIC ,and then added to climatic SIC as the external force of test. In this study, on the intraseasonal time scale, we show that atmospheric circulation anomalies evolved from spring to summer, and spring Arctic SIC anomalies were thermally and dynamically consistent with atmospheric circulation,surface temperature and rainfall anomalies in spring and summer, especially contributing to less spring rainfall in east China and more summer rainfall in northeast,central China. While on short time scales, the initial adjustment of the atmospheric circulation is characterized by relationship of out of phase in geopotential height anomalies in the lower and upper troposphere locally, and three weeks after, the out-of-phase turned progressively to more barotropic with the responses propagating to remote areas, at last, the quasi-equilibrium stage of adjustment is reached in six weeks. The remote responses are regarded as a stationary Rossby wave generated thermally and dynamically through an anomalous turbulent heat fluxes and atmospheric circulation internal varieties. At first, the surface heat fluxes were changed by anomalies in Arctic SIC, and then a large scale stationary Rossby wave was triggered through the interaction with atmospheric circulation. The lower tropospheric response is baroclinic and thus favors upward emanation of wave activity flux in negative anomaly area of height; while, in upper level, the energy is dispersed to east Asia through teleconnection, the internal varieties keeping the energy, and then effects the climate of this area.