Regional Characteristics of Drought Anomalies in North China

Drought indices of spring and summer for 24 stations in North China were defined by using the monthly precipitation and temperature data during 1951~1996, considering soil moisture and evaporation. The analysis of drought indices for the whole region and individual stations showed that the indices can display drought anomolies objectively. By using rotated empirical orthogonal function analysis, based on the principle of maximum variance, three regional patterns of spring drought and four regional patterns of summer drought were divided. Furthermore, the meteorological meaning of the maximum centers for the various spatial rotated modes was also discussed.