Abstract: The issue of water shortage and related eco-environmental degradation in North China is one of the major emerging problems in China. Precipitation is the most important factor for water resources. Based on the historical series of instrumental data of annual precipitation obtained from 25 gauging stations and a long-term historical drought-flood grade dataset during the period of 1470-2000 obtained from 15 gauging stations in North China, the character of precipitation variability was analyzed by means of power spectrum and continuous wavelet transform. It was found that the precipitation was characterized by obvious seasonal changes, quasi-biennial oscillation, and quasi-19-year interdecadal periodicity. The M-K test results showed that abrupt changes in annual precipitation occurred around 1914 and 1964. As for the historical flood/dryness grade time series, it was characterized by the 4-5-year ENSO mode interannual oscillation, the quasi-10-year and quasi-24-year interdecadal variabilities and 50-80-year centurial periodicity.

Key words: North China, precipitation, drought-flood character