The Analysis On Interdecadal Climate Variability Of China And Its Numerical Simulation

Decadal climate variability is the projected background of monthly, quarterly, andinterannual climate variability, has a longer impact on climate change. With the developmentof science and the improvement of the social needs, decadal climate variability in theextensive development to become an emerging research topic within the scope of the worldsince the1990s.The results indicated that the annual precipitation of China has the characteristics ofmulti time scales and notablely regional differences of the interannual and interdecadalvariability. The fluctuant energy of annual precipitation in the northernpart of China is larger,and the contribution of interannual variation. However,the reality in the southern part ofChinais reverse. The interdecadal variabilities of annual precipitation in the Northeast Chinaand Northwest China are remarkable and at the same phase.The contribution of interdecadalvariability to annual precipitation of the whole Cjoma currently are in the phase turning fromlow to high, and might continue rising in the future10-30years.The trend of season averaged precipitation anomaly percentage is not quite the same inthe past50years. Generally speaking, the trend of spring and summer shows unconspicuous,and that of autumn shows a significant decline while the trend in winter increased obviously.The phase of summer is often the same as that of winter, however it often exhi bits thecharacteristics of the anti-phase in spring and autumn. With the different regions and seasons,the intensity of interannual and decadal oscillation energy are different. The intensity is impact not only by the periodic oscillation of the seasonal precipitation, but also by theperiodic oscillations of regional precipitation. The intensity of the northern region and theplateau is mainly affected by the geographical difference, while that of the south is changedby the season.Hadcm3model can basically reflect the variation of annual precipitation, and thesimulation of summer precipitation is better than that of annual precipitation. With theHadcm3, the simulation of first mode is worse than that of the second, it mainly shows inpositive and negative center.Based on Hadcm3model, the annual precipitation and summer precipitation in the next30years are simulated. The results show that the precipitation have interannual changes after2020s, and the precipitation increases from north to south in the eastern region, in addition,south of Northewest has more precipitation while the southewest has minimum. EOF analysissuggests that the first eigenvector of the national annual precipitation mainly appears thepattern of “-+”, and the second eigenvector appears the pattern of “-+-”, however the firsteigenvector of summer precipitation mainly appears the pattern of “-+”, and the secondeigenvector appears the pattern of “+-+” from south to north in the next30years.