APPLICABILITY OF SINGULAR VALUE DECOMPOSITION AND SINGULAR CROSS-SPECTRUM TO DIAGNOSE OF RAINFALL IN NORTH CHINA

Based on the monthly mean precipitation data of 1965-2000 from 73 meteorological stations in North China, the diagnostic analyses of the January Northern Hemisphere 500 hPa height field and the winter Northern Pacific Ocean sea surface temperature (SST) field associated with summer precipitation over North China are made by singular value decomposition (SVD) and singular cross spectrum analysis (SCSA) methods.The results show that there is a close PNA teleconnection pat tern between 500 hPa height field and summer North China precipitation when the summer precipitation anomaly is positive.ENSO has a definite impact on summer North China precipitation, but there is not no table relation between summer precipitation and winter ENSO in the Northern Pacific Ocean when the precipitation anomaly is positive.The key regions of interaction between North China precipitation and Northern Hemisphere 500 hPa height field and that between precipitation and SST are further found.For the interaction between North China precipitation and 500 hPa height field, the dominated coupled oscillation periods are quasi-two years and quasi-seven years.For the interaction between North China precipitation and SST, the periods are longer———the shortest is the quasi-2-year oscillation and the longest is 10-or 11-year oscillation.