Validation of TROPOMI/S5P NO2 products using PANDORA measurements over GEMS domain

Abstract

As collections of quality-assured and nearly real-time data from ground-based observation networks are in high need of geophysical validation for GEMS, the world first geostationary satellite to monitor diurnal variation of trace gases and aerosols over the Asian region with high spatial/temporal resolution, international and domestic efforts to expand of ground-based observation networks have been going on. In these regards, two Pandora instruments started to be newly operated at Seoul and Ulsan sites in Korea. Also, Pandora Asian Network (PAN) initiated by NIER. Korea will be expanded PAN into South East Asian region beyond Korea, China, and Japan in addition. Pandora products have been used to assess the target accuracy of LEO satellite data (i.e., TROPOMI L2 products). The previous studies showed that the slope of regression line for NO2 VCD was very low due to (a) spatial resolution difference between LEO satellite and PANDORA and (b) short lifetime of NO2 (*in case of neglecting uncertainty of AMF). In this study, we especially try to validate the initial L2 NO2 VCD product of GEMS, retrieved during the IOT period by using Pandora observation data and other ground-based observation data as well.