To investigate the impact of two CO2 observation datasets obtained from the Korean Peninsula on the surface CO2 flux estimation over Asia, the two datasets are assimilated into the CarbonTracker (CT) inverse modeling system and the estimated surface CO2 fluxes are analyzed. Anmyeon-do (AMY) and Gosan (GSN) sites in the Korean Peninsula have observed surface CO2 mole fraction since the late 1990s. To investigate the effect of assimilating the additional Korean observations on the surface CO2 flux estimation over Asia, two experiments are conducted. The reference experiment (CNTL) only assimilates observations provided by National Oceanic and Atmospheric Administration (NOAA), while the other experiment (EXP1) assimilates both NOAA observations and two Korean observation datasets. The results are analyzed for 9 years from 2003 to 2011 in Asia region because both AMY and GSN datasets exist almost completely for this period. The annual average of estimated biosphere CO2 flux of EXP1 shows more flux absorption in summer and less flux emission from fall to spring compared to CNTL, mainly on Eurasia Temperate and Eurasia Boreal regions. When comparing model results to independent CO2 concentration data from surface stations and aircraft, the root mean square error is smaller for EXP1 than CNTL. The EXP1 yields more reduction on uncertainty of estimated biosphere CO2 flux over Asia, and the observation impact of AMY, GSN sites on flux estimation is approximately 11%, which is greater than other observation sites around the world. Therefore, the two CO2 observation sets in the Korean Peninsula are useful in reducing uncertainties for regional as well as global scale CO2 flux estimation.
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The authors appreciate the reviewers' valuable comments. The authors are grateful to National Institute of Meteorological Sciences at KMA for CO2 mole fraction data at AMY and GSN sites, NOAA ESRL for providing observations and resources to run CarbonTracker, and NIES Japan for CONTRAIL data. The authors also acknowledge atmospheric CO2 measurement data providers and cooperating agencies at China Meteorological Administration, Japan Meteorological Administration, Commonwealth Scientific and Industrial Research Organization, Environment and Climate Change Canada, Instituto de Pesquisas Energeticas e Nucleares, Lawrence Berkeley National Laboratory, National Institute of Environmental Research, and National Center for Atmospheric Research. The simulations were primarily conducted using the cluster of the National Center for Meteorological Supercomputer of the Korea Meteorological Administration (KMA).
© 2022 Cho, Kim. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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