Publications

Lee, Y; Ahn, MH; Kang, MA; Eo, M; Kim, D; Moon, KJ (2024). Advantages of Inter-Calibration for Geostationary Satellite Sensors Onboard Twin Satellites. GEOPHYSICAL RESEARCH LETTERS, 51(14), e2024GL109364.

Abstract
To address the increasing demand for diurnal information on trace gases and aerosols, a series of geostationary (GEO) satellite programs called GEO-constellation have been initiated, with the launch of the Geostationary Environment Monitoring Spectrometer (GEMS) onboard Geostationary Korea Multi-Purpose Satellite 2B (GK2B). To assess the sensor performance of GEMS in orbit, the current work suggests employing an inter-calibration methodology involving the Advanced Meteorological Imager (AMI) aboard its twin satellite, GK2A. Twin satellites have a significant advantage in obtaining collocation data sets across diverse spatiotemporal, angular, and atmospheric conditions, enabling rigorous collocation criteria effectively reducing mismatch uncertainty. The results present robust correlation coefficients over 0.99, revealing the current calibration characteristics of the sensors. This research emphasizes the advantages of the GEO-GEO inter-calibration, particularly the capability of analyzing spatial and temporal dependencies. These findings confirm the mutual benefit of utilizing the sensors in similar configurations, highlighting their importance for future satellite monitoring endeavors. Understanding diurnal changes in air pollutants is crucial for grasping how these substances move and disperse in the air, thereby aiding efforts to reduce pollution. In this regard, satellites have a distinct advantage in observation owing to their wide spatial coverage at regular time intervals. GEMS is one of the geostationary sensors providing such information for the Asia-Pacific region, nearly 7-8 times a day. To evaluate the reliability of GEMS, this study proposes an inter-calibration method by comparing GEMS observations with those of AMI aboard GK2A. These satellites have a unique advantage as they fly close to each other, observing the Earth with matched optical viewing paths. Scenes simultaneously observed by AMI and GEMS exhibit strong agreement, thus revealing the inherent observation characteristics of each sensor. These findings confirm the mutual benefit of utilizing the sensors in similar configurations for satellite monitoring during the operation. Inter-calibration based on ray-matching between geostationary satellite sensors onboard twin satellites Implementation of collocation process in the visible wavelengths and the application of weighted statistics for ensuring collocation stability The novel advantages of the GEO-GEO inter-calibration approach for future applications

DOI:
10.1029/2024GL109364

ISSN:
0094-8276