Global Warming Observations from Commercial Jets

An environmental observation and monitoring project started in April 1993 by the JAL (Japan Airlines) Foundation recently marked its 200th flight. The project has been conducted in collaboration with Japan Airlines and the Meteorological Agency's Research Institute, with the cooperation of the Ministry of Land, Infrastructure and Transport.

It is difficult to make regular observations of conditions in the upper troposphere from ground- or ship-based meteorological observation bases. This monitoring project is the world's first attempt to measure greenhouse gas concentrations using scheduled commercial flights. JAL aircraft flying between Sydney and Narita (between Brisbane and Narita since April, 2002) were loaded with specially-made equipment to collect air samples in-flight. Upon arrival in Japan, the equipment is sent to the Meteorological Agency's Research Institute for analysis.

The observations have continued twice a month since April 1993, and provided much valuable information, including the following findings:
-Seasonal fluctuations of CO2 concentrations caused by plant photosynthesis occur even in the upper troposphere.
-The increase in CO2 concentrations in the upper troposphere shows a similar trend to increases at the Earth's surface.
-Based on the above two findings, it can be hypothesized that CO2 emitted at the Earth's surface reaches the upper troposphere by convection.
-The CO2 originating mainly at mid-latitudes of the northern hemisphere is carried to the southern hemisphere on high-altitude air currents. A part of this CO2 travels to the mid-latitudes of the southern hemisphere, later proceeding northwards to the equator via air currents at lower altitudes.
-The CO generated from forest fires in Asia and Oceania as a result of the severe El Nino phenomena in 1997 reached the upper troposphere, with major impacts on atmospheric composition.

The observational data obtained from this project is provided to organizations and researchers in Japan and abroad through the World Meteorological Organization's World Data Center for Greenhouse Gases (WDCGG) and the JAL Foundation. It is being use to study the actual spatial and temporal fluctuations of greenhouse gases, in order to clarify the mechanisms of carbon circulation and global warming, and to improve the accuracy of weather forecasting techniques.



Posted: 2002/11/13 05:14:16 AM
Japanese version