Greenhouse Gas Measurements using the Boseong Tall Tower during the ASIA-AQ Campaign

In this study, a tall tower measurements system was established on the Boseong Tall Tower (BTT, 34.76˚N, 127.21˚E) to monitor greenhouse gases from long-range transport. The in situ measurement system uses a cavity ring-down spectroscopy (CRDS) analyzer, which continuously measures carbon dioxide (CO2) and methane (CH4) concentrations at 300 m above ground level. The system was tested during the ASIA-AQ campaign in Feb 2024. A 4-point calibration was performed for quality assurance (QA), with measurement accuracies of 0.25 ppm for CO2 and 2.0 ppb for CH4. During the study period, the average CO2 concentration was 435.98 ± 6.93 ppm, and the average CH4 concentration was 2046.1 ± 24.8 ppb. When compared with the hourly data from domestic stations, the BTT time series data showed similar concentration levels, effectively representing the inflow and outflow of greenhouse gases across the Korean peninsula. However, high CO2 concentrations were observed under specific wind directions, suggesting the need for further analysis of long-term changes in the CO2/CH4 ratio.