17 Feb 2022
17 Feb 2022
Status: this preprint is currently under review for the journal AMT.

Highly resolved mapping of NO2 vertical column densities from GeoTASO measurements over a megacity and industrial area during the KORUS-AQ campaign

Gyo-Hwang Choo1, Kyunghwa Lee1, Hyunkee Hong1, Ukkyo Jeong2,3, Wonei Choi4, and Scott J. Janz3 Gyo-Hwang Choo et al.
  • 1Environmental Satellite Center, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon, Republic of Korea, 22689
  • 2Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland, USA 20740
  • 3NASA Goddard Space Flight Center, Greenbelt, Maryland, USA, 20771
  • 4Division of Earth Environmental System Science, Major of Spatial Information Engineering, Pukyong National University, Busan 48513, South Korea

Abstract. The Korea-United States Air Quality (KORUS-AQ) campaign is a joint study between the United States National Aeronautics and Space Administration (NASA) and the South Korea National Institute of Environmental Research (NIER) to monitor megacity and transboundary air pollution around the Korean Peninsula using airborne and ground-based measurements. Here, tropospheric nitrogen dioxide (NO2) slant column density (SCD) measurements were retrieved from Geostationary Trace and Aerosol Sensor Optimization (GeoTASO) L1B data during the KORUS-AQ campaign (May 1 to June 10, 2016). The retrieved SCDs were converted to tropospheric vertical column densities using the air mass factor (AMF) obtained from a radiative transfer calculation with trace gas profiles and aerosol property inputs simulated with the Community Multiscale Air Quality (CMAQ) model and surface reflectance data obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS). For the first time, we examine highly resolved (250 m × 250 m resolution) tropospheric NO2 over the Seoul and Busan metropolitan regions, and the industrial regions of Anmyeon. We reveal that the maximum NO2 VCDs were 4.94 × 1016 and 1.46 × 1017 molecules cm−2 at 9 AM and 3 PM over Seoul, respectively, 6.86 × 1016 and 4.89 × 1016 molecules cm−2 in the morning and afternoon over Busan, respectively, and 1.64 × 1016 molecules cm−2 over Anmyeon. The data retrieved from the GeoTASO airborne instrument were well correlated with those obtained from the Ozone Monitoring Instrument (OMI) (r = 0.65), NASA’s Pandora Spectrometer System (r = 0.84), and NO2 mixing ratios obtained from in situ measurements (r = 0.78 in the afternoon). Based on our results, GeoTASO is useful for identifying hotspots of NO2 and its spatial distribution in highly populated cities and industrial areas.

Gyo-Hwang Choo et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2022-51', Anonymous Referee #1, 16 Mar 2022
  • RC2: 'Comment on amt-2022-51', Anonymous Referee #2, 23 Mar 2022

Gyo-Hwang Choo et al.

Gyo-Hwang Choo et al.


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Short summary
This study looked at morning and afternoon distribution of NO2 emissions in large cities and industrial areas in Korea, one of the largest NO2 emitters around the world, using GeoTASO, an airborne remote sensing instrument developed to support geostationary satellite missions. NO2 measurements from GeoTASO were compared with those from ground-based remote sensing instruments including Pandora and in-situ sensors.