New research published in Scientific Reports turns to aircraft data to fill gaps in emissions monitoring of global greenhouse gases. The research relied on high-precision atmospheric CO2 data from Japan’s aircraft observation program, CONTRAIL, which uses instruments onboard Japan Airlines' (JAL) commercial airliners to take emissions measurements.
“We analyzed vertical atmospheric CO2 mole fraction data obtained onboard commercial aircraft in proximity to 36 airports worldwide, as part of the Comprehensive Observation Network for Trace gases by Airliners (CONTRAIL) program,” write the authors of the international team.
In that way, they were able to look at trending measurements over airports in 34 major cities around the world. Airports provide a unique opportunity for observation because they are frequently located close to large cities.
In considering these measurements, the researchers began to notice certain trends. "We analyzed millions of observational data collected at and around the Tokyo Narita Airport and found clear CO2 enhancements when the wind comes from the Greater Tokyo Area," stated lead author Taku Umezawa, who is a researcher at the National Insititute for Environmental Studies, Japan. "That was also the case globally for other airports, such as Moscow, Paris, Beijing, Osaka, Shanghai, Mexico City, Sydney, and others."
Co-author of the study Hidekazu Matsueda is a researcher at the Meteorological Research Institute, Japan who has taken this project on as a life-long study. "Following the aircraft measurements conducted between Tokyo and Australia that I initiated in 1993, and had maintained during my entire career, the CONTRAIL program continuously expanded its global network and has provided numerous data to understand the carbon budget of this planet," commented Matsueda.
The overall implications of this study are significant. The researchers say that their findings prove that aircraft measurements can be used to complement CO2 emissions data from ground stations and satellites, particularly in places where on-the-ground measurement systems are limited.
"Despite these complex conditions under which the measurements are made, it was very interesting that we found a relationship between the magnitude of CO2 variability and CO2 emissions from a nearby city," concludes co-author Kaz Higuchi.