This study conducted a statistical analysis on the temporal and spatial distribution characteristics of the frequency, days and intensity of heatwaves in China in 1961-2010 based on the summer daily maximum temperature data of 753 stations over China and the heatwave indicators developed based on the significant increase in mortality. The results show that the high frequency, days and intensity of heatwaves occurred in the Jianghuai region, most of the Jiangnan region, as well as eastern Sichuan Basin, with the highest frequency in northern Jiangxi and northern Zhejiang, the largest days in northern Jiangxi and northern Zhejiang, and the highest intensity in northern Zhejiang. The frequency, days and intensity of heatwaves have temporally showed an overall increasing trend in the past 50 years, with a strong stage variation characteristic: the frequency (intensity) of summer heatwaves displayed a decreasing (weakening) trend from the 1960s to the early 1980s, followed by an increasing (strengthening) trend from the late 1980s up to now. The regional heatwave change characteristics were also distinctive, with a significant strengthening (increasing) trend in the northern and western parts of North China, central-northern part of Northwest China, the central part of South China, the Yangtze River Delta and the southern Sichuan Basin, but a remarkable decreasing trend in the local areas of the southern Huanghuai region, the northern Jianghuai region and the Hanjiang River basin. Since the 1990s, the frequency, days and intensity of heatwaves in China have significantly increased and strengthened, and its spatial range has also expanded.%利用全国753个站1961-2010年夏季逐日最高气温资料和基于死亡率明显增加而制定的高温热浪指标的已有研究成果,统计分析了我国高温热浪频次、日数和强度的时空分布特征.结果表明:我国的高温热浪频次、日数、强度高值区基本相同,均在江淮、江南大部和四川盆地东部等地,其中江西北部、浙江北部高温热浪频次最高,高温日数最多；浙江北部高温强度尤为突出.近50年来我国夏季高温热浪的频次、日数和强度总体呈增多、增强趋势,但也呈现明显的阶段性变化特征,20世纪60-80年代前期高温热浪频次和强度呈减少(弱)趋势,80年代后期以来,高温热浪频次和强度呈增多(强)趋势.区域变化特征明显,华北北部和西部、西北中北部、华南中部、长江三角洲及四川盆地南部呈显著增多(强)趋势；而黄淮西部、江汉地区呈显著减少趋势.自20世纪90年代以来,我国高温热浪的范围明显增大.
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