基于模式分析一次沙尘暴过程中沙尘表面非均相化学过程对中国地区污染物浓度的影响

A Modeling Study of Impacts of Dust Surface Heterogeneous Chemistry on Atmospheric Pollutants Concentrations in China during a Dust Storm Event

利用戈达德对地观测系统(GEOS)提供的再分析气象场GEOS-5驱动的GEOS-Chem模式,模拟中国地区2009年4月22~29日沙尘暴期间沙尘气溶胶表面非均相化学过程对我国污染物的影响。模拟结果表明,沙尘暴期间,全国平均沙尘硝酸盐和沙尘硫酸盐浓度分别为0.2μg m^(-3)和0.4μg m^(-3),占总硝酸盐(非沙尘硝酸盐与沙尘硝酸盐之和)和总硫酸盐(非沙尘硫酸盐与沙尘硫酸盐之和)的24%和10%。我国西部地区沙尘硝酸盐占比(>80%)要大于其他地区,而西部地区的沙尘硫酸盐占比则要小于下游地区。考虑非均相化学反应后,沙尘暴期间,全国平均的二氧化硫(SO_2)、硝酸(HNO_3)、臭氧(O_3)、非沙尘硫酸盐、总硫酸盐、非沙尘硝酸盐、总硝酸盐、NH_3、总铵盐浓度变化量分别为-7%、-15%、-2%、-8%、3%、-2%、14%、21%、-5%。

In this study,the impact of dust surface heterogeneous chemistry on the pollutants over China during 22-29 April 2009 is investigated by using GEOS-Chem model driven by GEOS-5 assimilated meteorological field from the Goddard Earth Observing System(GEOS).During the dust storm period,the simulated concentrations of dust nitrate and dust sulfate averaged over China are about 0.2μg m^-3 and 0.4μg m^-3,respectively,which account for 24%of the total nitrate(sum of non-dust and dust nitrate)and 10%of the total sulfate(sum of non-dust and dust sulfate),respectively.The percentage of total nitrate accounted for by dust nitrate in western China is higher than those in other regions by more than 80%,while the percentage of the total sulfate accounted for by dust sulfate is lower than those in the down-wind areas.After considering the dust surface heterogeneous chemistry,the simulated changes in concentrations of sulfur dioxide(SO2),nitric acid(HNO3),ozone(O3),non-dust sulfate,total sulfate,non-dust nitrate,total nitrate,NH3,and ammonium averaged over China during the dust storm event are about-7%,-15%,-2%,-8%,3%,-2%,14%,21%,and-5%by percentage,respectively.