基于GEMS地球同步卫星探测器的中国地区氮氧化物高时空分辨率研究

中国氮氧化物污染严重，虽然近年来排放有所下降，但下一步精准减排难度大，其中一个重要原因是现有排放清单、地基观测、极轨卫星遥感等手段存在缺陷，对于高时空分辨率条件下氮氧化物的变化特征和成因的认识不足，尤其缺乏诸多地区（特别是郊区和农村）污染物的日内变化信息。本项目拟基于近期成功发射的世界首个可测量对流层二氧化氮的地球同步卫星探测器GEMS，利用其高时间分辨率（白天逐小时）和高水平分辨率（在华北地区约7 x 8 km2）特点，改进自主开发的POMINO算法并应用到GEMS，获得中国及周边地区对流层二氧化氮垂直柱浓度产品，进一步利用EOF-EEMD等工具定量分析氮氧化物污染的高时空分辨率变化特征，改进自主开发的PHLET算法反演主要城市及其周边地区的白天逐小时高分辨率氮氧化物排放，探索氮氧化物变化的驱动机制，为精准减排提供依据。

China is confronted with high-level nitrogen oxides (NOx) pollution. Although Chinese anthropogenic emissions have declined over the past few years, further reductions are challenging, in part because of deficiencies in high-resolution information of NOx pollution based on current emission inventories, ground-based measurements and polar-orbiting satellite remote sensing. In particular, there is lack of information on the diurnal variation of NOx especially over suburban and rural areas. In this study, we propose to investigate the characteristics and drivers of NOx pollution over China at high spatial and temporal resolutions, based on the recently launched world’s first geostationary satellite instrument capable of measuring tropospheric NOx on a (daytime) hourly basis at 7 x 8 km2 over North China. We plan to modify and apply our POMINO algorithm to retrieve tropospheric vertical column densities of nitrogen dioxide, and further use the EOF-EEMD statistical analysis and visualization tool to diagnose the spatiotemporal characteristics of NOx at a high resolution. In addition, we will modify and apply our PHLET algorithm to retrieve NOx emissions at selected highly polluted cities and their surrounding areas. We will further address the driving mechanisms of NOx variations at resolutions of concern. Our studies will provide new scientific findings to facilitate emission control and pollution mitigation.