Cross-evaluation of GEMS tropospheric ozone retrieval performance using OMI data and the use of an ozonesonde dataset over East Asia for validation

Juseon Bak, Kang Hyeon Baek, Jae Hwan Kim, Xiong Liu, Jhoon Kim, Kelly Chance

Research output: Contribution to journalArticle


The Geostationary Environment Monitoring Spectrometer (GEMS) is scheduled to be launched in 2019-2020 on board the GEO-KOMPSAT (GEOstationary KOrea Multi-Purpose SATellite)-2B, contributing as the Asian partner of the global geostationary constellation of air quality monitoring. To support this air quality satellite mission, we perform a cross-evaluation of simulated GEMS ozone profile retrievals from OMI (Ozone Monitoring Instrument) data based on the optimal estimation and ozonesonde measurements within the GEMS domain, covering from 5° S (Indonesia) to 45° N (south of the Russian border) and from 75 to 145° E. The comparison between ozonesonde and GEMS shows a significant dependence on ozonesonde types. Ozonesonde data measured by modified Brewer-Mast (MBM) at Trivandrum and New Delhi show inconsistent seasonal variabilities in tropospheric ozone compared to carbon-iodine (CI) and electrochemical condensation cell (ECC) ozonesondes at other stations in a similar latitude regime. CI ozonesonde measurements are negatively biased relative to ECC measurements by 2-4DU; better agreement is achieved when simulated GEMS ozone retrievals are compared to ECC measurements. ECC ozone data at Hanoi, Kuala Lumpur, and Singapore show abnormally worse agreements with simulated GEMS retrievals than other ECC measurements. Therefore, ECC ozonesonde measurements at Hong Kong, Pohang, Naha, Sapporo, and Tsukuba are finally identified as an optimal reference dataset. The accuracy of simulated GEMS retrievals is estimated to be ∼5.0% for both tropospheric and stratospheric column ozone with the precision of 15% and 5%, which meets the GEMS ozone requirements.

Original languageEnglish
Pages (from-to)5201-5215
Number of pages15
JournalAtmospheric Measurement Techniques
Issue number9
Publication statusPublished - 2019 Sep 27

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

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