Comparative evaluation of CO2 concentrations across administrative regions with temperate climates in Northeast Asia: potentials and constraints

This paper examined carbon concentrations across administrative regions with temperate climates in Northeast Asia (NEA) using Level 3 data of column-averaged CO2 concentrations (XCO2) that were derived from the Greenhouse Gases Observing Satellite (GOSAT) National Institute for Environmental Studies (NIES) retrieval algorithm. Data were analyzed for March through June 2009-2012 (boreal spring). The highest and lowest XCO2 concentrations ranged from 397.7 to 384.1ppm, and the estimated XCO2 distribution across administrative regions varied widely between 394.3 and 387.2ppm. Low values were observed in the northern region of the study area (northern part of central China and South Korea). In contrast, high concentrations of XCO2 were observed in the southeastern (Japan) and southwestern (China) regions. The five cities with the highest concentrations were located in China (Shanghai, Zhejiang and Jiangsu) and Japan (Kyushu and Shikoku). Among the 27 administrative regions analyzed, Kyushu showed the highest levels. There is still considerable debate about whether GOSAT data have sufficient reliability. This paper represents an early effort to compare carbon concentrations across administrative regions. Therefore, caution should be exercised when using the ranking numbers as a basis for regional comparisons.