Measurement report: Atmospheric CH₄ at regional stations of the Korea Meteorological Administration–Global Atmosphere Watch Programme: measurement, characteristics, and long-term changes of its drivers

Abstract. To quantify CH4 emissions at policy-relevant spatial scales, the Korea Meteorological Administration (KMA) started monitoring its atmospheric levels in 1999 Anmyeondo (AMY) and expanded to Jeju Gosan Suwolbong (JGS) Ulleungdo (ULD) 2012. The system consists of a cavity ring-down spectrometer (CRDS) new cryogenic drying method, with measurement uncertainty (68 % c.i. (confidence interval)) ± 0.7–0.8 ppb. determine regional characteristics each KMA station, we assessed level relative local background (CH4xs), analyzed surface winds bivariate polar plots, investigated diurnal cycles. We also compared measured stations those Mt. Waliguan (WLG) station China Ryori (RYO) Japan. CH4xs followed order AMY (55.3 37.7 ppb) > JGS (24.1 10.2 ULD (7.4 3.9 ppb). Although was observed well-mixed air AMY, it higher than other stations, indicating that affected not only by sources but distant masses. Annual mean highest among all East Asian while seasonal amplitude smaller JGS, which strongly summer biogenic activities. From long-term records confirmed growth rate increased 3.3 ppb yr−1 during 2006/2010 8.3 from 2016 2020, is similar global trend. Studies indicated recent accelerated CH4-growth related sources. However, δ13CH4 indicates trend Asia derived both fossil fuel 2006 2020. high-quality data can help understand changes Asia.