四川省霾的气候变化特征
Climate Change Characteristics of Haze in Sichuan Province

选用四川省1951~2016年共66年41个逐日气象霾日观测资料，采用小波分析等方法分析了四川省霾的月、季、年的时空变化特征及长期变化趋势。结果表明：1) 四川省66年平均霾日数为14.7 d。11月~次年3月为霾日多发月份，7月~9月为霾日较少月份。1月最多，为34.54 d，最少的是9月，为6.48 d。2)霾日的空间分布不均，霾天气主要发生在四川省的东部，西部较少，具有一定的局地性。一年四季中四川省内始终存在三个霾日数的高值中心，分别为以雷波、乐山、雷波为中心的区域，最多的站点是雷波，多年平均15.27 d。3) 秋季、春季和夏季霾日数的大值区站点几乎都集中在与冬季霾日大值相同的区域。四川省内霾日的时间变化特征为冬季最多，夏季最少，春、秋季居中，春季大于秋季。夏季的7、8月霾日数最少，为6.9 d；春季和秋季居中；冬季1月霾日数最多，为12.7 d，四川省霾日的季节分布和中国大部分地区相似。
Based on observed data from 41 weather stations during 1951 to 2016 in Sichuan Province, temporal and spatial distribution of the number of haze days and its seasonal and annual trends were analyzed by wavelet analysis and other methods. The results indicate that: 1) the average number of haze days in Sichuan in the past 66 years was 14.7 days. From November to March of the following year, haze days are frequent months, and July to September are months with fewer haze days. The most in January was 34.54 d, and the least was in September, which was 6.48 d. 2) The spatial distribution of haze days is uneven, and haze mainly occurs in the eastern part of Sichuan and is less in the western part, which has a certain locality. There are always three high-value centers of haze days in Sichuan throughout the year, namely Leibo, Leshan, and Leibo. The most frequent site is Leibo, annual average 15.27 d. 3) Almost all stations in the high-value area of haze days in autumn, spring and summer are concentrated in areas with the same high value of haze days in winter. The time variation of haze days in Sichuan is the most in winter, the least in summer, the middle of spring and autumn, and the greater in spring than in autumn. Summer has the least number of haze days in July and August, at 6.9 days; spring and autumn are in the middle; January in winter has the most haze days, at 12.7 days. The seasonal distribution of haze days in Sichuan Province is similar to most parts of China.