Effect of Atmospheric CO2 Observations in Asia on the Optimization of Surface CO2 Flux
Jinwoong Kim1, Hyun Mee Kim2, Chun-Ho Cho3, Andrew R Jacobson4,5, Motoki Sasakawa6, Toshinobu Machida6, Mikhail Arshinov7 and Nikolay Fedoseev8, (1)Yonsei University, Seoul, Korea, Republic of (South), (2)Yonsei University, Seoul, South Korea, (3)National Institute of Meteorological Research, Jeju, Korea, Republic of (South), (4)NOAA, Global Monitoring Laboratory, Boulder, United States, (5)University of Colorado at Boulder, CIRES, Boulder, United States, (6)National Institute of Environmental Studies, Earth System Division, Tsukuba, Japan, (7)V.E. Zuev Institute of Atmospheric Optics, Tomsk, Russia, (8)Russian Academy of Sciences, Melnikov Permafrost Institute, Yakutsk, Russia
Abstract:
Understanding sources and sinks of atmospheric CO
2 is important to estimate the impact of CO
2 on climate change and environment. Although surface CO
2 sources and sinks in Asia affect the global carbon cycle considerably, the atmospheric CO
2 observation network is sparse in Asia. Due to the sparse observations in Asia, the estimated surface CO
2 fluxes in the Eurasian Boreal region differ considerably depending on the inversion systems used in the estimation. In this study, to investigate the effect of additional CO
2 observations in the Eurasian Boreal region on the surface carbon flux analysis in the globe and Asia, two experiments using different observation data set were performed with CarbonTracker developed in NOAA. One experiment was conducted using a data set that includes additional observations of Siberian tower measurement data (Japan-Russia Siberian Tall Tower Inland Observation Network: JR-STATION) and data observed in China and India, and the other experiment was conducted using a data set without the above additional observations.
Global balance of the source and sink of surface CO2 fluxes was maintained for both experiments with and without additional observations. While the magnitude of the optimized surface CO2 flux uptake in Siberia was decreased for the experiment with the additional observations, the magnitude of the optimized surface CO2 flux uptake in Western Europe and North America was increased. This result implies that the impact of the Siberian observation data is as large as other continuous measurements (e.g., tower measurements in North America). The average RMSE and bias of the model CO2 concentrations calculated using the optimized CO2 flux exhibited better agreement with the observed CO2 concentrations when the additional observations were used, which implies that the additional observations provide beneficial impact on the surface CO2 flux analysis in Asia.
