Research On The Spatio-temporal Evolution Characteristics Of Different Kinds Of Heat Waves In China

According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the global warming has become an indisputable fact. Under the background of global warming, the frequency of heat waves will become more and more frequent, which not only endangered the human health but also affected the normal operation of industrial and agricultural as well as the daily life, what’s more, the frequency, duration and intensity of heat waves will be enhanced in the near future. Studying the occurance and development rules of heat waves not only could further enriched the theory of heat waves, it was of graet significance in taking scientific and effectice disaster prevention and reduction measures with local conditions and sustainable development of the society as well. Therefore, based on the daily meteorological observation data from 642 national stations from 1960 to 2013, on the basis of the difination of heat waves by the China Meteorological Administration, and the frequency, duration, intensity of heat waves were the main quantitative description indices, the spatio-temporal differentiation variations characteristic of different kinds of heat waves were discussed in this article with the method of principal component analysis, cluster analysis, trend analysis, Mann-Kendall test and wavelet analysis method, etc. The major conclusions of the article were as follows:(1) Heat waves in China can be divided into three kinds, the dry heat waves, common heat waves and wet heat waves. The dry heat waves were mainly distributed in in China’s aridand semi-arid area, the wet heat waves were centered in the east monsoon region and the coastal zone of China, and the common heat waves can be seen as a transitional type of dry and wet heat waves.(2) Through the distribution of the average frequency, duration and intensity of different kinds heat waves, the dry heat waves were mainly distributed in the Tarim Basin and the Junggar Basin, the common heat waves were centered in the southern Shanxi, Henan, northern Anhui, southern Hebei, and the wet heat waves were centered in the the mid-lower reaches of the Yangtze River. In all, the Tarim Basin and the Junggar Basin as well as the the mid-lower reaches of the Yangtze River are the most frequent regions in China, the average frequency, duration and intensity of heat waves are more than 3 times,20 days,10 ℃, respectively.(3) From the interdecadal spatial variation characteristics of different kinds of heat waves, the dry heat waves, common heat waves and wet heat waves were all showed an revolution of decreasing-increasing-decreasing, the 1990s is the most increasing area of dry and the common heat waves, while the wet heat waves occured in 1980s; the least increasing area of frequency, duration, intensity of dry heat waves appeared in 1980s, the common heat waves occured in 1980s,2000s,1970s respectively, whereas the wet heat waves were all emerged in the 1990s.(4) From the interannual variation characteristics of different kinds of heat waves, the dry heat waves were all presented a significant increasing trend, the major cycle of the frequency, duration and intensityof dry heat waves were 22 years,11 years and 22 years, and mutated in 1995 from less to more; the common heat waves were showed a slight decreasing trend in all, the abrupt change of frequency, duration, andintensity of heat waves happened in 1969,1969, and 1962 respectively, the major cycle was 5 years; the frequency of wet heat waves showed an obvious increasing trend, and mutated in 2005 from less to more, the duration and intensity of heat waves presented increasing trendbut not significantly, not pass the significance at 0.05,the intensity of the wet heat waves themajor cycle was 22 years,22 years and 12 years, and there were no obvious abrupt change of the duration and intensity of wet heat waves.