Interdecadal and interannual variation characteristics of rainfall in North China and its relation with the northern hemisphere atmospheric circulations

With the data of monthly precipitation of 26 stations in North China and American NCAR/NCEP monthly reanalysis atmosphere variables, by method of Singular Value Decomposition (SVD), we have investigated the variation features of precipitation in North China at interdecadal and interannual time scales, and also its relation with the atmospheric circulations in the Northern Hemisphere. The results show that it's necessary to do time scale separations to precipitation and atmosphere variables, otherwise, the outcomes of SVD reflect only the characteristics of interannual time scale without interdecadal time scale. Corresponding to interdecadal and interannual time scales of precipitation in North China, there exist significant differences in the anomalies of atmospheric circulations. In connection with the remarkable interdecadal shift of precipitation occurring in the late 1970s in North China, all the atmospheric circulations have the same shift as well, together with a propagation process from ground surface to the upper troposphere.