Multi-Time Scale Analysis on Characteristics of Precipitation in Hebei Province

Based on the precipitation data observed monthly of 19 weather stations in Hebei province from 1960 to 2011, three methods, linear trend estimation, Mann-Kendall test as well as Morlet wavelet transformation, were adopted to analyze the characteristics of precipitation trend, abrupt change points and cyclical variations under the circumstance of multi-time scales in the past 52 years. Annual precipitation had a decreasing trend, and precipitation in spring increased dramatically, meanwhile precipitation of summer decreased significantly; however, precipitations in autumn and winter were fluctuated in an acceptable range. There were various abrupt change points both in annual precipitation series and in spring as well as in summer, yet any abrupt change points were found in autumn and winter. Multi-scale periodicities were found by wavelet analysis in annual and seasonal precipitations.