A23A-0272
Expected trace gas and aerosol retrieval accuracy of the Geostationary Environment Monitoring Spectrometer
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Ukkyo Jeong1, Jhoon Kim2, Xiong Liu3, Kyung-Hwa Lee4, Kelly Chance5 and Chul H. Song4, (1)Yonsei University, of Atmospheric Sciences, Seoul, South Korea, (2)Yonsei University, Seoul, South Korea, (3)Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States, (4)GIST Gwangju Institute of Science and Technology, Gwangju, South Korea, (5)Harvard-Smithsonian, Cambridge, MA, United States
Abstract:
The predicted accuracy of the trace gases and aerosol retrievals from the geostationary environment monitoring spectrometer (GEMS) was investigated. The GEMS is one of the first sensors to monitor NO2, SO2, HCHO, O3, and aerosols onboard geostationary earth orbit (GEO) over Asia. Since the GEMS is not launched yet, the simulated measurements and its precision were used in this study. The random and systematic component of the measurement error was estimated based on the instrument design. The atmospheric profiles were obtained from Model for Ozone And Related chemical Tracers (MOZART) simulations and surface reflectances were obtained from climatology of OMI Lambertian equivalent reflectance. The uncertainties of the GEMS trace gas and aerosol products were estimated based on the OE method using the atmospheric profile and surface reflectance. Most of the estimated uncertainties of NO2, HCHO, stratospheric and total O3 products satisfied the user’s requirements with sufficient margin. However, about 26% of the estimated uncertainties of SO2 and about 30% of the estimated uncertainties of tropospheric O3 do not meet the required precision. Particularly the estimated uncertainty of SO2 is high in winter, when the emission is strong in East Asia. Further efforts are necessary in order to improve the retrieval accuracy of SO2 and tropospheric O3 in order to reach the scientific goal of GEMS. Random measurement error of GEMS was important for the NO2, SO2, and HCHO retrieval, while both the random and systematic measurement errors were important for the O3 retrievals. The degree of freedom for signal of tropospheric O3 was 0.8 ± 0.2 and that for stratospheric O3 was 2.9 ± 0.5. The estimated uncertainties of the aerosol retrieval from GEMS measurements were predicted to be lower than the required precision for the SZA range of the trace gas retrievals.
