9:30 AM - 9:45 AM
[AAS07-03] Continuous observation of CO2 concentration in Chiba by using a trace gas analyzer and characteristics of its concentration variation
Keywords:carbon dioxide, green house gas, grobal warming, ground remote sensing observation
Global warming, which has been threatening human life in recent years by causing extreme weather disasters, is primarily driven by anthropogenic carbon dioxide (CO2) emissions from burning fossil fuels. To take effective CO2 emission countermeasures, it is essential to understand the factors behind CO2 concentration fluctuations in more detail. For this purpose, in addition to satellite observations, it is essential to continuously observe CO2 concentration fluctuations using highly accurate ground-based observations. However, the number of ground observation sites that continuously observe CO2 concentration in large cities with high anthropogenic emissions is extremely limited worldwide. Against this background, the purpose of this study was to conduct continuous observation of CO2 concentrations in Chiba, Japan, and to clarify the characteristics of the concentration fluctuations. Therefore, we conducted continuous ground-based observations of atmospheric CO2 concentrations from January 1 to March 21, 2022, using a trace gas analyzer (LI-7810, LI-COR) at Chiba University, located in the Tokyo metropolitan area. In addition, the black carbon (BC) mass concentration was continuously observed by the black carbon monitor, and the nitrogen dioxide (NO2) concentration by the MAX-DOAS method at Chiba University. Utilizing these simultaneous observations, this study analyzes the average hourly concentrations of CO2, BC, and NO2, and examines the correlation among them. As a result, we obtained a specific correlation in the concentration fluctuations from January 1 to March 21, 2022, which was conducted as the initial analysis. Combining this result with the fact that black carbon and nitrogen dioxide have a high percentage of anthropogenic emissions, it was found that substances with a higher rate of fossil fuel origin correlate better with CO2. Thus, it was confirmed that a high proportion of CO2 emitted in the Chiba area is of fossil fuel origin.
From the equation of the regression line, it was also found that the CO2 concentration in the Chiba area is approximately 422 - 425 ppm as a background value (but as it may be affected by measurement drift, it is a reference value), from which an increase of 1 μg/m3 of BC corresponds to the rise of approximately 40 ppm of CO2, and an increase of 1 ppb of NO2 corresponds to an increase of about 2 ppm of CO2.
From the equation of the regression line, it was also found that the CO2 concentration in the Chiba area is approximately 422 - 425 ppm as a background value (but as it may be affected by measurement drift, it is a reference value), from which an increase of 1 μg/m3 of BC corresponds to the rise of approximately 40 ppm of CO2, and an increase of 1 ppb of NO2 corresponds to an increase of about 2 ppm of CO2.