基于TropOMI和OMI的中国氮氧化物卫星遥感及排放和环境影响研究

中国氮氧化物污染严重，对臭氧和颗粒物的形成有重要影响，但是其排放清单和地基观测存在诸多不足，时空变化特征、排放和环境影响尚不完全清楚。利用卫星遥感可反演得到对流层二氧化氮（NO2）垂直柱浓度资料，特别是将于2017年发射的TropOMI探测器可提供迄今为止最高水平分辨率（星下点像元面积为7 x 7 km2）的NO2遥感，极有助于定量研究氮氧化物污染问题。申请人已经基于现有的OMI探测器发展了POMINO算法并获得了相应的NO2产品，本项目拟改进该算法并应用到TropOMI以反演得到新的覆盖中国地区的高分辨率NO2产品，定量分析反演误差，结合TropOMI和OMI资料作2004年以来（特别是“十三五”期间）长时间序列、高水平分辨率的NO2时空分析，结合GEOS-Chem模型反演高分辨率下的氮氧化物排放及其时间演化，定量分析氮氧化物排放变化对臭氧和颗粒物的影响，为下一步减排策略提供科学依据。

China is confronted with high concentrations of nitrogen oxides (NOx), particularly their impacts on formation of ozone and particulate matter (PM) pollution. However, the spatial variation and temporal evolution of NOx and associated environmental impacts over China are not clearly understood, due to inadequacies and inaccuracies in emission inventory and ground-based measurements. Satellite remote sensing can be used to retrieve vertical column densities (VCDs) of tropospheric nitrogen dioxide (NO2), a quantity proven powerful to study NOx pollution and impacts. In particular, the TropOMI sensor to be launched in 2017 will provide unprecedented high-resolution (pixel size is only 7 x 7 km2 at nadir) measurements of NO2, essential for detailed analyses of NOx pollution characteristics and environmental impacts. Based on the OMI sensor currently in orbit, we have established a POMINO algorithm to retrieve tropospheric NO2 VCD. This proposal will implement an improved version of POMINO to further retrieve tropospheric NO2 VCDs from TropOMI. We will combine NO2 data retrieved from OMI and TropOMI to analyze long-term variability and trends of NO2 since 2004 (especially during the thirteenth “Five-Year Plan” period over 2016-2020) at a high spatial resolution. We will further combine satellite data and GEOS-Chem simulations to derive surface emissions of NOx, their spatiotemporal variability and impacts on ozone and PM pollution. Our studies will provide new scientific findings to facilitate further emission control.