Characterizing spatial-temporal changes of heat waves in China using center of gravity analysis

Many regions of the world have experienced dramatic changes in occurrence of heat waves. Investigating changes in their spatial patterns is of great importance for understanding the causes of heat waves and their related processes. This paper, based on observation data collected from 611 meteorological stations, used the weighted mean center tool in ArcGIS to calculate China's heat wave center of gravity and to trace its migration over the past five decades. The results show an association between its north-south movements and the change of Arctic Oscillation Index, especially for the period after the mid-1980s, during which substantial north-south displacements took place. This study also revealed a close relationship between its west-east movements and the change in annual number of heat wave days before the 1990s, after which it was replaced by a time-dependent relationship that showed increasing heat wave trend only.