1961-2005年中国霾日气候特征及变化分析

利用1961-2005年中国霾日统计资料,对中国霾的时空气候分布特征、变化趋势进行了详细分析,并探讨了霾变化的可能原因及其与太阳总辐射、日照时数变化的关系。结果表明：近45年来,中国年和四季霾日的空间分布特征均呈现东多西少的空间分布态势,东部地区集中在三个多发区,分别为长江中下游、华北和华南;季节变化,除东北地区、青藏高原、西北西部四季霾日均很少且变化不明显外,其余大部分地区均呈现为冬季多,夏季少,春秋季居中的特点。近45年,全国平均年霾日数呈现明显的增加趋势,2004年为最高值。我国东部大部地区主要呈现增加趋势,尤其霾多发地区,如长江中下游、珠江流域及河南西部等地,霾日增加幅度大,趋势显著,人类活动造成的大气污染物增加及天气气候变化是这些地区霾日呈现增加趋势的可能原因,我国西部地区和东北大部地区则以减少趋势为主。华北、长江中下游地区、华南地区霾日变化趋势与日照时数变化趋势相反,霾的增加是造成太阳总辐射减少的主要原因之一。东北地区、西北地区、西南地区、青藏高原霾日变化和日照时数变化均呈现不明显的减少趋势,但由于这些地区霾日发生少,其变化不会对日照时数和太阳总辐射变化造成很大的影响。

The Climatic Characteristics and Change of Haze Days over China during 1961-2005

In the context of haze days during the period 1961-2005 over China,the characteristics and changes of temporal and spatial distribution of haze days as well as possible reason and the relationship with the trend of global solar radiation and sunshine duration are analyzed.Result shows that the spatial pattern of annual and seasonal haze days presents more in eastern and less in western China.There are three regions with the number of haze days coinciding with the economically developed regions:the lower and middle reaches of the Yangtze River,North China and South China.Apart from Northeast China,the Qinghai-Tibet Plateau and western part of Northwest China with small annual variation and less in values,the annual variation of haze days is obvious in most of the other regions.The haze days are maximum in winter and the minimum in summer.In recent 45 years,the national mean annual haze days exhibited obvious increasing trends with the maximum in 2004.In most parts of eastern China,the number of haze days shows increasing trends,particularly in areas such as the middle and lower reaches of the Yangtze River,Pearl River Basin and west of Henan Province with obvious trends and the increments of haze days are great,where the increasing air pollution caused by human activities and climate change are the possible reasons.In western China and Northeast China,the trend is decreasing.In North China,the middle and lower reaches of the Yangtze River and South China,the trends of haze days and sunshine durations are opposite.The increasing haze days may be one of the reasons leading to the decrease of global solar radiations.In Northeast China,Northwest China,Southwest China and Tibet-Qinghai Plateau,the trends of haze days show slight decrease and are identical to the change of sunshine duration.But in these regions the haze seldom occurs and the change of it will not greatly affect the change of sunshine duration and global solar radiation.