Winter temperature anomalies of the North China Plain and macroscale extratropical circulation patterns

Abstract

Monthly temperature anomaly data for 38 weather stations in the North China Plain and its vicinity were analyzed for winter months (November–March) during 1951–1992. The study area was divided into two subregions based on principal component analysis. Spearman's rank correlation coefficients between the scores of the temperature anomaly principal components and geopotential height anomalies in the Eastern Atlantic–Eurasia–Western Pacific realm suggested different macroscale circulation patterns that influence the spatial variation of temperature anomalies in the subregions. Temperature anomalies in the southern subregion were more closely related to the northern Asian teleconnection pattern, while those in the northern subregion were more closely related to the Eurasian pattern. Composite maps of geopotential height anomalies indicated that the extreme positive and negative temperature anomalies in the southern subregion were probably associated with the widening and narrowing of the Asian trough, while those in the northern subregion were associated with the filling and deepening of the trough. The characteristics of the Asian trough were strongly influenced by the variation of the geopotential heights over Siberia. In stepwise regression, the teleconnection indices explained ca. 22 and 37% of the variation in the mean temperature anomalies in the southern and northern subregions respectively, indicating a stronger association between temperature anomaly in the northern subregion and macroscale circulation patterns than that in the southern subregion. Copyright © 1999 Royal Meteorological Society