摘要
本文利用区域空气质量模式RAQMS(Regional Air Quality Model System),对2009年春季中国东部气溶胶主要化学成分及其分布进行了模拟研究。与泰山站观测资料的对比结果显示,模式能比较合理地反映气溶胶浓度的逐日变化特征。整体上,模式对无机盐气溶胶的模拟好,分别高估和低估黑碳和有机碳气溶胶浓度,其原因与排放源、二次有机气溶胶化学机制和模式分辨率的不确定性有关。模拟结果显示,春季气溶胶浓度高值主要集中于华北、四川东部、长江中下游等地区。受东南亚生物质燃烧和大气输送的影响,中国的云南和广西等地区有机碳浓度高于中国其他地区。中国西北部沙尘浓度较高,而且向东输送并影响到中国东部和南方部分地区。中国东部的华北、四川东部、长江中下游等地PM_(2.5)(空气动力学直径在2.5微米以下的颗粒物)污染严重,4月平均PM2_(2.5)浓度超过了我国日平均PM_(2.5)浓度限值。中国东部泰山站的观测和模拟结果都显示近地面硝酸盐浓度超过硫酸盐,中国北部对流层中硝酸盐的柱含量也大于硫酸盐,而在中国南部则相反,这一方面与春季中国云量南多北少的分布特征以及云内液相化学反应有关,另一方面也与南北温差对气溶胶形成的影响有关。就整个中国东部而言,虽然硫酸盐的柱含量(46 Gg)仍大于硝酸盐(42 Gg),但比较接近,反映出我国氮氧化物排放迅速增加的趋势。春季中国地区对流层中PM_(10)(空气动力学直径在10微米以下的颗粒物)及其化学成分柱含量分别为:990.8Gg(PM_(10)),52.6 Gg(硫酸盐),48.2 Gg(硝酸盐),32.1 Gg(铵盐),22.9 Gg(黑碳)和74.1 Gg(有机碳),有机碳(OC)中一次有机碳(POC)和二次有机碳(SOC)分别占60%和40%,中国东部PM_(10)中人为气溶胶和沙尘分别占30%和70%,反映了春季沙尘对我国大气气溶胶的重要贡献。
A regional air quality model system （RAQMS） was applied to investigate the distribution of major aerosol chemical components in eastern China in spring 2009. The comparison of model results with observations at Taishan station indicates that the model system is able to represent the day-to-day variation of aerosol concentrations reasonablywell. In general, the model simulates concentrations of inorganic aerosols well, but it tends to overpredict and underpredict black carbon and organic carbon aerosol concentrations, respectively, mainly due to the uncertainties in emission inventory, the chemical mechanism of secondary organic aerosol formation, and the model resolution. The model results show that near the surface, high aerosol concentrations mainly occurred in the Huabei Plain, the east of Sichuan Province, in the middle and lower reaches of the Yangtze River. The organic carbon aerosol concentrations in the southern parts of Yunnan and Guangxi provinces were larger than those in other regions of China, due to the transport effect of biomass burning emissions from Southeast Asia. Soil dust was rich in northwestern China and can be transported toward eastern China and portions of southern China. The PM2.s （the particulate matter with aerodynamic diameter smaller than 2.5 micrometers） levels in the Huabei Plain, east of the Sichuan Province and the middle and lower reaches of the Yangtze River, were seriously high, exceeding the daily mean PM2.s limit of the national standard. Both observations and model simulations showed that nitrate exceeded sulfate concentrations at Taishan station. The regional burden of nitrate within the troposphere in northern China was close to or in excess of that of sulfate, whereas in southern China, the opposite was the case; this was associated with the distribution of clouds in spring （there are more clouds in southern China at that time than that in northern China） and the relevant aqueous chemical mechanisms, as well as the different temperature effects on aerosol fo
出处
《大气科学》
CSCD
北大核心
2014年第3期399-409,共11页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金资助项目41075106
