Cities are responsible for more than 70% of the global total greenhouse gas (GHG) emissions. A study by an international team, published in Scientific Reports, examined the data collected by commercial airliners and showed the potential of the aircraft data to contribute to the global GHG emission monitoring. The CONTRAIL (Comprehensive Observation Network for TRace gases by AIrLiners) program is Japan’s unique aircraft observation project. Since 2005, the CONTRAIL team has achieved high-precision atmospheric CO2 measurements using instruments onboard Japan Airlines’ (JAL) commercial airliners.
Recently, the team analyzed thousands of vertical ascending and descending measurements over airports and characterized CO2 variations over 34 major cities worldwide for the first time. Airports are often located in the proximity of large cities to ensure convenient access. The CONTRAIL aircraft fly up and down over Narita International Airport many times nearly on a daily basis (7,692 times in total during 2005-2016) and are able to obtain atmospheric chemical signature of the Greater Tokyo Area (~several tens km away). With similar geographical locations of major airport relative to large urban centers, the research team examined the data collected around global airports in order to retrieve urban CO2 emission signatures from the data.
The team also examined the magnitude of CO2 variability in the lowermost atmosphere over these airports. The results show that the commercial airliner-based CO2 dataset can consistently provide urban emission estimates when combined with atmospheric modeling framework. The advantage of commercial airliners is the great global spatial coverage of the measurements even in regions where we only have sparse greenhouse gas measurement networks, especially places where securing ground-site measurements is challenging, such as in developing countries.
Source: EurekAlert
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