摘要
利用全国664站1961-2012年逐日霾观测资料、降水量、平均风速和最大风速资料,分析中国霾日数变化特征及其气候成因.结果表明:我国年霾日数分布呈明显东多西少特征,中东部大部地区年霾日数在5～30 d,部分地区超过30d,西部地区基本在5d以下.霾日数主要集中在冬半年,冬季最多,秋季和春季次之,夏季最少,12月是霾日数最多的月份,约占全年霾日数的2成.我国中东部地区冬半年平均霾日数呈显著的增加趋势(1.7 d/10a),霾日数显著增加时段主要在1960年代、1970年代和21世纪初,在1970年代初和21世纪初发生了明显均值突变.从区域分布来看,华南、长江中下游、华北等地霾日数呈增加趋势,而东北、西北东部、西南东部霾日数呈减少趋势.持续性霾过程增加,持续时间越长的霾过程比持续时间短的霾过程增加更为明显.不利的气候条件加剧了霾的出现.霾日数与降水日数在中东部地区基本以负相关为主,中东部冬半年降水日数呈减少趋势(-4d/10a),表明降水日数的减少导致大气对污染物的沉降能力减弱.另一方面,霾日数与平均风速和大风日数以负相关为主,而与静风日数则以正相关为主,冬半年平均风速和大风日数减小,静风日数增加,表明风速减小导致空气中污染物不易扩散,从而更易形成霾天气.
The characteristics of haze days and the climatic background were analyzed by using daily observations of haze,precipitation,mean wind speed and maximum wind speed of 664 meteorological stations from 1961 to 2012.The results show that haze days are significantly more in eastern China than in western China.The annual haze days are 5-30 d in most central-eastern China,more than 30 d in some areas,but less than 5 d in western China.Haze days are mainly concentrated in winter half year,the most in winter,followed by autumn and spring,and the least in summer.Haze days are the most in December,nearly 20% of annual haze days.The haze days in winter half year averaged in central-eastern China have a significant increasing trend of 1.7 d per decade during 1961-2012.There were great increases in haze days in the 1960s,1970s and the beginning of the 21st century.There was a significant abrupt change of haze days in the early 1970s and the beginning of the 21st century.Haze days of winter half year increased in South China,the middle-lower reaches of the Yangtze River and North China,but decreased in Northeast China,eastern Northwest China and eastern Southwest China from 1961 to 2012.The consecutive haze process is becoming more and more.The longer the process,the more significant the process' s increasing trend.Unfavourable climate conditions exacerbated the occurrence of haze.The correlation coefficient is mainly negative in centraleastern China between haze days and precipitation days in winter half year,and the precipitation days showed decreasing trends in most China,with the rate of around-4 d per decade in central-eastern China,which reduces the sedimentation capacity of atmospheric pollutants.During 1961-2012,the correlation coefficient is mainly negative in central-eastern China between haze days and mean wind speed and strong wind days,but positive between haze days and breeze days in winter half year.The mean wind speed and strong wind days reduced,while the breeze days increased in most China,which leads to the
出处
《气候变化研究进展》
CSCD
北大核心
2013年第5期313-318,共6页
Climate Change Research
基金
全球变化研究国家重大科学研究计划(2012CB955902)
关键词
霾
冬半年
降水日数
风速
haze
winter half year
precipitation days
wind speed
