未来全球PM2.5浓度时空变化特征的模拟

摘要

根据政府间气候变化专门委员会第五次评估报告(IPCC AR5)给出的气溶胶及其前体物的不同排放情景RCP2.6(低排放)、RCP4.5(中等排放)和RCP8.5(高排放),利用国家气候中心的气溶胶-气候在线耦合模式,分别模拟了2010～2030和2030～2050年总PM2.5(人为和自然PM2.5的总和)及其中人为和自然气溶胶柱含量的时空变化,并预估了的绿色排放情景RCP4.5下中国地区人为和自然气溶胶对总PM2.5浓度变化的贡献.结果表明,在3种排放情景下,2010～2030年PM2.5柱含量变化的空间分布基本相似.在欧洲、北非及其西侧的洋面上,PM2.5呈现不同程度的增加,其中以北非及其西侧的洋面上的增加最为明显,而阿拉伯半岛东部PM2.5则明显减少.在RCP4.5排放情景下,中国地区年均PM2.5地表浓度的减少量约为2.55μg/m3,其中人为气溶胶的贡献约为28％,自然气溶胶的贡献约为72％.2030～2050年,3种排放情景下PM2.5柱含量变化的空间分布差异较大,在RCP4.5和RCP8.5排放情景下,非洲北部及其西侧洋面的PM2.5显著增加,而东亚地区的PM2.5显著减少,而RCP2.6排放情景与前2种情景的结果区别很大.在RCP4.5排放情景下,中国地区PM2.5及其中人为和自然气溶胶均在2010～2030年的基础上进一步减少,而且人为气溶胶在其中的贡献(约为34％)也有所增加.%According to the emission scenarios of aerosols and their precursors,RCP2.6 (low emission),RCP4.5 (medium emission) and RCP8.5 (high emission) scenarios given by the Fifth Assessment Report of Intergovernmental Panel on Climate Change (IPCC AR5),the temporal and spatial variations of the concentrations of total PM2.5 (the sum of anthropogenic and natural aerosols),anthropogenic and natural aerosols in PM2.5 over the globe from 2010 to 2030 and 2030 to 2050,as well as the contributions of anthropogenic and natural aerosols to these variations under the green emission scenario (RCP4.5) over China were simulated in this work,using an aerosol-climate online coupled model from National Climate Center.Results show that from 2010 to 2030,the spatial variations of the column concentrations of PM2.5 under the three emission scenarios were basically similar to each other.The column concentrations of PM2.5 increase over Europe,North Africa,and the ocean to the west of North Africa,but the increase over North Africa and the ocean to the west of it was more significant than that over Europe.However,the column concentrations of PM2.5 decrease over the Arabian peninsula.The annual mean surface concentrations of PM2.5 over China decreased approximately by 2.55μg/m3,with the anthropogenic aerosols accounting for about 28％ and the natural aerosols accounting for about 72％ under RCP4.5 scenario.From 2030 to 2050,the spatial variations of the column concentrations of PM2.5 differred greatly under the three different emission scenarios.The column concentrations of PM2.5 increased apparently over North Africa and ocean to the west of it,while decreased over East Asia under both RCP4.5 and RCP8.5 scenarios.Whereas,the results under RCP2.6 scenario were quite different from RCP4.5 and RCP8.5 scenarios.In China,the column concentrations of PM2.5,as well as the anthropogenic and natural aerosols in PM2.5,were reduced further than the previous period under RCP4.5 scenario,with the contributions (about 34％) of anthropogenic aerosols increasing.