Japan Airlines (JAL) and its research partners said they will transfer sensors used in a government-backed atmospheric carbon dioxide (CO2) monitoring programme, known as CONTRAIL, to Boeing 787-9 aircraft, preserving one of the world’s longest-running airborne climate datasets as Japan retires older widebody jets and expands climate surveillance across new regions.
The programme, jointly led by the airlines and Japan’s national research institutes, has collected more than 30,000 greenhouse gas datasets from about 22,000 commercial flights over 30 years. This has formed the core of the country’s upper-atmosphere CO2 monitoring and the datasets are a critical reference for global climate modelling.
The shift follows the retirement of JAL’s Boeing 777 fleet that had previously carried the sensors, leaving only one operational aircraft earlier this year and raising concerns over potential data disruption, according to a statement by Japan’s Ministry of the Environment on 5 December.
The first modified 787-9 jet will begin observation on a JAL flight from Tokyo’s Narita airport to Frankfurt on Wednesday, after a ferry flight from Haneda earlier in the day, with four more aircraft to be converted by the end of the financial year. This restores the the total fleet carrying the sensors to five aircraft. A ferry flight is a non-commercial flight used solely to reposition an aircraft from one location to another, usually without paying passengers.
Launched in 1993 by JAL, the JAL Foundation and the Meteorological Research Institute of the Japan Meteorological Agency, and later joined by the National Institute for Environmental Studies (NIES) and aircraft interiors maker Jamco, the project equips commercial aircraft with instruments that continuously measure atmospheric CO2 and collect air samples of methane and nitrous oxide at near-stratospheric cruising altitudes.
The system consists of a continuous CO2 analyser capable of running for up to two months and an automatic sampler that collects 12 air samples per round trip, both developed by Jamco and already fitted to the first 787-9 plane.
Data collected are released publicly via NIES servers, and Japan now holds one of the world’s largest upper-atmosphere CO2 datasets, with more than 10,000 observations over Narita, 1,700 over Bangkok and 1,500 over Sydney alone.
Scientists of the project say the aircraft sensors offer continuous, high-frequency, wide-area and vertical measurements which are unavailable from ground stations or satellites, allowing researchers to track how emissions move across hemispheres and how agricultural cycles, forest fires and industrial activity shape atmospheric composition.
The upgraded fleet will extend monitoring deeper into the southern hemisphere via Melbourne, closer to the Arctic through Frankfurt routes, and for the first time into the Middle East via Doha, while also resuming observations over India through Delhi, where crop cycles have already been shown to influence seasonal CO2 fluctuations. Researchers previously detected emissions spikes over Singapore during Indonesia’s 2015 forest fires comparable to Japan’s annual national output.
“Through atmospheric observation using next-generation aircraft, we will continue to track changes in greenhouse gas absorption and emissions at both the global scale and across major metropolitan areas, while also using the data to verify the effectiveness of emissions-reduction measures,” said the ministry.
Japan’s programme operates alongside a smaller number of comparable efforts overseas. In Europe, a government-backed research infrastructure known as In-service Aircraft for a Global Observing System (IAGOS), equips selected long-haul aircraft operated by carriers including Lufthansa, Air France, China Airlines, Cathay Pacific and Iberia with atmospheric monitoring instruments.
Building on the Measurement of Ozone and Water Vapour by Airbus In-Service Aircraft (MOZAIC) programme launched in 1994, designed to measure the composition of the atmosphere using commercial passenger aircraft during routine flights, and formalised in 2011, IAGOS measures ozone, carbon monoxide and water vapour on every equipped flight, with optional modules adding greenhouse gases such as carbon dioxide and methane, as well as aerosols and cloud particles. Data are used in evaluating European climate and air-quality models and in studies cited by the IPCC.
China has also expanded airborne atmospheric monitoring in recent years through its meteorological and aviation research institutes, using dedicated research aircraft and modified transport planes to measure greenhouse gases and regional air pollution.
These campaigns are typically designed around specific scientific studies or policy questions, and their datasets are usually published through individual research projects rather than via long-running, open operational databases like Japan’s CONTRAIL or Europe’s IAGOS systems.
