[대기] [8.1] 특별세미나 안내 (이예은 박사, 이화여자대학교)
일시 : 2025-08-01(금) 10:30 ~ 11:30
연사 : 이예은 박사
소속 : 이화여자대학교
문의 :
장소 : 501동 504호 세미나실
Title: Calibration and Validation Strategies for Ensuring Level 1 Data Reliability of Environmental Satellite Sensors
[Abstract]
[Abstract]
To meet the growing demand for diurnal information on trace gases and aerosols in the atmosphere, a series of satellite programs consisting of the GEO-ring has been initiated. The series started off with the launch of the Geostationary Korean Multi-Purpose Satellite-2B (GK- 2B) in 2020, followed by the Tropospheric Emissions: Monitoring of Pollution (TEMPO) in 2023 and the expected launch of Sentinel-4 this year. Onboard GK-2B, the Geostationary Environment Monitoring Spectrometer (GEMS) is dedicated to observing the Asia-Pacific region, providing spectral radiance in the 300-500 nm range to provide spectral information regarding the targeted retrieval products.
For long-term operation of satellites, robust calibration and validation strategies are essential to ensure the observation data reliability of satellite sensors. GEMS has operated over five years since its launch, and the observation characteristics have gradually changed under the severe space environment. In this regard, this research aims to develop post-launch calibration and evaluation methodologies of GEMS, especially for Level 1B products which are used as input for the retrieval of geophysical variables. Particularly, this study presents a comprehensive approach to assess the radiometric calibration accuracy of GEMS, integrating both onboard calibration and inter-calibration methodologies.
The calibration updates have been specifically developed to address angular dependence and diffuser degradation. Solar calibration, one of onboard calibration systems of GEMS, serves as the foundation for both correction methodologies. The evaluation of the calibration updates for the Level 1B products of GEMS is performed by utilizing the Advanced Meteorological Imager (AMI) onboard the twin satellite, GK-2A, and the polar-orbiting instruments such as Tropospheric Monitoring Instrument (TROPOMI) and Ozone Mapping and Profiler Suite (OMPS). The ray-matching approach with AMI reveals high temporal and seasonal correlation, while also identifying a positive bias in GEMS. Additionally, vicarious calibration using stable Earth targets confirms consistent bias patterns and highlights stray light effects in the shorter wavelength range (below 320 nm), necessitating further correction efforts.
This combined strategy using onboard calibration system and inter-calibration approaches provides a validated framework for enhancing Level 1 data reliability from environmental satellite sensors. The findings offer practical insights for maintaining long-term calibration reliability, which is critical for the accuracy of Level 2 atmospheric products and the overall integrity of GEO-ring satellite missions.
첨부파일 (1개)
- Abstarct_YeeunLee.pdf (61 KB, download:10)
