近50年春季沙尘活动及其对PM_(10)质量浓度的影响

Spring Dust Activities over Northern China and Its Impacts on PM_(10) Pollution in Recently 50 Years

利用中国北方847个地面气象台站观测的天气现象,从沙尘日数的时空分布、变化趋势等方面对1961 2012年中国北方春季沙尘活动进行了分析。结果表明,中国西北部的沙漠地带是春季沙尘暴和扬沙的多发和频发区。除个别台站,绝大部分北方站点的沙尘暴日数、起沙日数均呈显著下降趋势。1961 2012年中国北方区域平均的春季沙尘暴日数、起沙日数变化趋势分别为-1.2 d·(10a)-1和-2.3 d·(10a)-1,下降趋势显著。另外,沙尘暴的影响范围也逐步缩小。通过分析大气环境监测的PM10质量浓度(ρPM10)日平均值数据表明,发生沙尘时,北京、石家庄、济南、兰州、西宁的日空气质量易超标。ρPM10日平均值与沙尘持续时间呈显著正相关,即沙尘持续时间越长,ρPM10日平均值增幅越大。

Temporal and spatial distribution of the spring dust activities over northern China from 1961 to 2012 were analyzed based on the sandstorm days( SDs) and the combined sandstorm and blowing dust days( CSBDs),which were calculated by the observation of weather phenomena from 847 northern surface stations. The results show that the desert terrains in northwest China are the high-incidence area of sandstorm and blowing dust occurrences. Almost all the northern stations,except a few,have significant decline trends in the spring SDs and the spring CSBDs. The trends of northern China mean SDs and CSBDs are- 1. 2 d·( 10a)- 1and- 2. 3 d·( 10a)- 1respectively,which are both significant. Furthermore,the sandstorm impacting area is shrinking. Based on the atmospheric environment monitored daily PM10 concentration,it indicates that Beijing,Shijiazhuang,Jinan,Lanzhou and Xining are more likely to have nonattainment days when encounter dust events. Daily mean PM10 concentration has a significant positive correlation with sand and dust duration,and longer the duration is,more the concentration increases.