Effect of continental sources and sinks on the seasonal and latitudinal gradient of atmospheric carbon dioxide over East Asia

•Examination of regional scale atmospheric CO2 column concentration over East Asia.•The latest regional scale CO2 simulation was conducted and evaluated.•The recent ACOS-GOSAT, satellite CO2 retrieval data was applied for the region.•The characteristics of atmospheric CO2 spatiotemporal variability over the East Asia.•Identification of the main driving forces (sources/sinks) for the variabilities.

Here we demonstrate the sharp seasonal and latitudinal gradient of atmospheric CO2 over East Asia, where there are relatively few ground-based observations. The Greenhouse gases Observing SATellite (GOSAT) column-averaged dry air CO2 mole fraction (xCO2) retrieved by NASA's Atmospheric CO2 Observations from Space (ACOS) (2009-2011) program and GEOS-Chem nested-grid CO2 results are used. The strong anthropogenic emissions mainly from China and intensive vegetation uptake from northeastern Asia lead to a clear seasonal change of the xCO2 between spring maximum and summer minimum (>10 ppm). In particular, the steep latitudinal gradient of summer time xCO2 by 3-5 ppm in the vicinity of the Korean Peninsula (32°N-44°N) is likely attributed to the large difference in CO2 fluxes among industry/cities, northeastern forests and the northwest Pacific region. This study represents the current progress to understand sub-continental scale atmospheric CO2 variabilities with recent satellite retrievals and nested-grid modeling.