HISTORIC CLIMATE VARIABILITY OF WETNESS IN EAST CHINA (960-1992) - A WAVELET ANALYSIS

Temporal and spatial climate variability in East China is analysed for the last 1033 years (AD 960-1992) based on historic annual grades of wetness for six regions in East China. This data set is subjected to a 'Mexican hat' wavelet transform for displaying variations of differen t frequencies at particular time points, persistent anomalies, and abr upt changes between them. The following results are noted: the persist ent dry stage 1120-1220 and wet stage 1280-1390 in the coastal regions are the outstanding features during the last 1033 years. For all regi ons an almost synchronous change occurs around 1890 from a weaker wet phase to a weaker dry phase; climatic variations on longer time-scales cover larger areas. On shorter time-scales, synchronous fluctuations are observed in fewer years than longer time-scale variability. (C) 19 97 by the Royal Meteorological Society.