A003-0016
A new TROPOMI product for tropospheric NO2 columns over East Asia with explicit aerosol corrections

Monday, 7 December 2020
Poster
Jintai Lin1, Mengyao Liu1, Hao Kong1, Folkert Boersma2, Henk Eskes3, Yugo Kanaya4, Kai Qin5, Pinhua Xie6 and Robert J D Spurr7, (1)Peking University, Beijing, China, (2)Royal Netherlands Meteorological Institute, De Bilt, Netherlands, (3)Royal Netherlands Meteorological Institute, De Bilt, 3730, Netherlands, (4)JAMSTEC Japan Agency for Marine-Earth Science and Technology, Research Institute for Global Change, Kanagawa, Japan, (5)China University of Mining and Technology, School of Environment Science and Spatial Informatics, Xuzhou, China, (6)Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, China, (7)Rt Solutions Inc., Cambridge, MA, United States
Abstract:
Satellite remote sensing of nitrogen dioxide (NO2) provides crucial information for atmospheric chemistry analyses, air quality studies, emission constraint and environmental management. The recently launched TROPOspheric Monitoring Instrument (TROPOMI) monitors the global environment with an unprecedented spatial resolution. Yet a large uncertainty exists in satellite NO2 data associated with a priori assumptions during the retrieval process, especially those associated with aerosol corrections, surface reflectance and NO2 vertical profiles. Here we present a new TROPOMI based product with explicit aerosol corrections, POMINO-TROPOMI, for tropospheric NO2 vertical column densities (VCDs) over East Asia. POMINO-TROPOMI is built upon our previous algorithm for the Ozone Monitoring Instrument (POMINO v2). It takes the tropospheric NO2 slant column density data from the official TM5-MP-DOMINO (OFFLINE) product, uses cloud top pressure data from the FRESCO-S based dataset, and re-calculates cloud fractions, NO2 air mass factors and lastly NO2 VCDs. Compared to the tropospheric NO2 VCD data in TM5-MP-DOMINO (OFFLINE), POMINO-TROPOMI shows stronger concentration gradients near emission source locations and better agrees with MAX-DOAS measurements (R2 = 0.75, NMB = 0.8% versus R2 = 0.68, NMB = 41.9%). Sensitivity tests suggest that implicit aerosol corrections, as in TM5-MP-DOMINO, lead to underestimations of NO2 columns by about 25% over the polluted Northern East China region. Reducing the horizontal resolution of a priori NO2 profiles would underestimate the retrieved NO2 columns over isolated city clusters in western China by 35% but with overestimates by more than 50% over many offshore coastal areas. The effect of a priori NO2 profiles is more important under calm conditions. Our retrieval product is available at http://www.pku-atmos-acm.org/acmProduct.php/.

References:

Liu, M.-Y., Lin, J.-T. *, Kong, H., Boersma, K. F., Eskes, H., Kanaya, Y., He, Q., Tian, X., Qin, K., Xie, P., Spurr, R., Ni, R.-J., Yan, Y.-Y., Weng, H.-J., and Wang, J.-X.: A new TROPOMI product for tropospheric NO2 columns over East Asia with explicit aerosol corrections, Atmos. Meas. Tech. Discuss., 2020, 1-22, doi:10.5194/amt-2019-500, 2020 (accepted for final publication in AMT)

<< Previous Abstract | Next Abstract >>