Multi-scale analysis of warm extremes over China

Abstract

Multi-scale features of warm extremes over China from 1961 to 2002 are evaluated using daily minimum and maximum temperature data. Different time scales of regional features of warm extremes are performed using rotated empirical orthogonal function (REOF) analysis and time scale departure methods. Clearly, significant differences are found in multi-scale of warm extremes. Significant increasing linear trends are detected in Northeast China, Inner Mongolia, northwestern part of Xinjiang, and southwestern China. However, in middle and lower reaches of Yangtze River, southern China and lower reaches of Yellow River basin, the linear trend is not remarkable, but the interannual pattern is the leading part, with several extreme peaks. The links with global temperature anomalies are studied, focusing in northeastern China and in middle and lower reaches of Yangtze River. It is found that the extreme indices show largest correlations with temperature anomalies in the Pacific Ocean. We detect that in northeastern and inland areas, high-related regions of frequency of warm extremes and the global temperature anomalies are broader, while the high-related area is smaller in the middle and lower reaches of the Yangtze River and the coastal regions.