华东雾和霾日数的变化特征及成因分析

The Changes and Causes of Fog and Haze days in Eastern China

基于华东449个气象站点1961-2007年的雾、霾、气温和露点温度数据、1980和2005年土地利用数据及2000-2007年MODIS气溶胶光学厚度数据,利用气候统计诊断、遥感和地理信息系统技术分析了华东雾、霾日数的气候变化特征及成因,结果表明:1961-2007年期间,华东雾日数在全年及四季都呈现出先增多后减少的年际变化特征,霾日数在全年及四季则呈现出逐渐增多的年际变化特征。在1961-1980年和1981-2007年期间,华东多数地区的雾日数分别呈现出增多和减少的变化趋势,霾日数则在两个时期都表现为增多趋势。华东雾日数和霾日数的变化特征与我国已有的研究结果一致,气象条件的变化、区域城市化和土地利用变化以及大气污染物排放量增加所导致的气温升高和城市热岛效应增强、空气湿度和风速降低、气溶胶光学厚度增加等是华东雾和霾出现频率变化的主要原因。

Based on the fog, haze, air temperature and dew point temperature data of 449 weather stations, the land use data in 1980 and 2005 and remote sensing aerosol optical depth from MODIS data during 2000-2007 in eastern China, the change characteristics and causes of fog and haze days from 1961 to 2007 was studied with climatologically statistical diagnosis methods, remote sensing and geographic information system （GIS） technology. The results indicate that from 1961 to 2007, the number of fog days increased firstly and then decreased, but that of haze days increased gradually. The number of fog days was the most in the 1980s, but the least during 2001-2007. The number of haze days was the most during 2001-2007, but the least in the 1960s. In the past 47 years, the number of fog days increased in most northern parts of eastern China, including Shandong, the northern and western parts of Jiangsu and the northern part of Anhui, but decreased in most southern parts of eastern China, especially in Fujian province. The number of haze days increased in most parts of eastern China from 1961 to 2007. In most parts of eastern China, the number of fog days increased during the period 1961-1980, but decreased during 1981-2007, and the number of haze days increased during the two periods of 1961-1980 and 1981-2007. The change characteristics of fog and haze are consistent with other results of China. The increases of mean annual temperature, urban heat island effects and aerosol optical depth, and the decreases of air humidity and wind speed, which resulted mainly from the change of weather and climate conditions, regional urbanization and land use change, and the increase of air pollution disposal, are the main causes for the changes of fog and haze days.