近53年山东省霾季节性特征的年代际变异

Inter-decadal Variations in the Seasonality of Haze over Shandong Province in Recent 53 Years

为了进一步认识山东省霾日长期变化特征,从而为政府决策和空气质量预报提供科学依据,基于山东省80 个气象站53 年（1961-2013）的观测资料分析,利用多项式及线性回归拟合、定义表示随季节和年际变化程度的变量如季节变化率、年际变化率等多种统计方法分析了近53 年来山东省霾日季节性的年际、年代际长期变化及空间分布规律,结果表明,山东上个世纪明显的冬季霾高发的典型季节性特征演变为本世纪模糊的季节差异,即霾多发时段随年际增长逐渐由冬季蔓延至秋季,夏季和春季.全省平均霾日的季节变率从60 年代的84.0%,70-80 年代的72.4%~73.6%,到90 年代跌至56.4%,而在本世纪的13 年低达42.3%,体现了山东霾日变化季节性的年代际特征,即近53 年季节差异在不断减小,霾趋于常年化发生的大气污染事件.霾日季节性的空间分布及年际变化特征还表明：近53 年山东霾日呈持续上升趋势,1990 年之前呈显著的增长趋势,1990 年之后上升缓慢,但维持霾高发的水平.霾日高发区域主要集中在济南地区,济宁-泰安-莱芜一带,枣庄-临沂一带,青岛地区和聊城西部地区,其中,高中心依次为济南的80.9 d·a^-1,临沂的78.2 d·a^-1 和青岛的69.0 d·a^-1.山东中东部的霾日年增长率整体高于西部地区,鲁中、鲁南及半岛南部地区是霾日年际增长高值区.山东省霾日年际变化趋势以夏季增长率最高,大部分地区的年际增长率都在4.5%·a^-1 以上,其次是秋季、春季霾日年际变化趋势,冬季霾日年际变化趋势普遍增长率最低,且大部分地区的变化率值为1.5%·a^-1 以上,近53 年来山东大部分地区出现了霾日模糊季节性变异.

To further explore the character of long-term change of haze over Shandong Province and provide theoretical basis for the government decision making and air quality forecasts, in this study by using the surface observation data(1961─2013) collected from 80 meteorological stations of Shandong Province, giving the definitions of seasonal change and inter-annual variability rates to measure the extent of the seasonal and inter-annual variations of haze, combined with several statistical methods such as polynomial and linear fitting, the seasonal characteristic of haze over Shandong Province in a recent 53 years were analyzed. The results indicate that the distinct seasonal characteristics of the occurrence of haze in the last century have become indistinct going in the 21th century, the frequent periods of haze days have been spreading from winter to autumn, summer and even spring. The seasonal change rate of haze days in 1960s was up to 84.0%, 1970s─1980s years ranged over 72.4%~73.6%, dropped to 56.4%in 1990s, while in recent 13 years of this century was as low as 42.3%, which indicated that the seasonal differences of haze days have steady declined. Haze pollution, previously happened in winter in Shandong Province, has tended to be a frequently occurring phenomenon in all over the year. The analysis on the inter-annual and spatial variations of haze over Shandong Province in different seasons also indicated that haze days averaged over Shandong Province exhibited an increasing trend during 1961─1990, and then grew slowly after 1990 with fluctuating at high pollution levels. The regions with high frequent haze are centered over Jinan, Jining-Taian-Laiwu area, Zaozhuang-Linyi area, Qingdao and the west area of Liaocheng city. The highest numbers of haze days in the 53-year average reached to 80.9, 78.2, 69.0 days per year for Jinan, Linyi, Qingdao respectively. In terms of the geographical distributions of inter-annual variability rate of haze, central-eastern Shandong experienced the higher inter-annual variation rates than western Shandong. The large inter-annual variations of haze days concentrated over the central and southern regions as well as the southern Shandong peninsula. Seasonally, the inter-annual increase rates peaked in summer with the values of higher than 4.5%·a-1, and then followed by autumn and spring, and dived in winter with the increase rate of lower than 1.5%·a-1. The indistinct seasonality of haze is exhibited in most areas of Shandong over the recent 53 years.