Trajectory (METEX) | Global Environmental Database (GED)

About METEX

In trajectory analysis, an air parcel is regarded as a mass point, and its moving path (trajectory) can be calculated using meteorological data. METEX (Meteorological Data Explorer), developed by the Center for Global Environmental Research (CGER), Earth System Division (ESD), National Institute for Environmental Studies (NIES), was used for this analysis.

Trajectory analysis can be utilized to estimate the pathway of air parcels to obtain information on the effect of high-concentration greenhouse gases or air pollutants to an observation point.

The following figure shows the trajectories passing over the Hateruma station in February and August of a certain year. An increase in CO₂ concentration has been observed at Hateruma station from autumn to winter every year. In addition to the natural increase due to the decreasing uptake of terrestrial plant, enhanced spikes were often linked to air coming from China. By using this analysis, one can investigate the fluctuation of CO₂ concentration in relation to economic activities.

This page provides tools to calculate not only a single trajectory for one point, but also trajectories for a fixed point at a regular interval as shown above, or for multiple points. The "Archives" provides 10-day backward trajectories for Hateruma and Cape Ochiishi stations, and animations of the CO₂ variations observed at Hateruma and Ochiishi stations along with 5-day back trajectories that are initialized at the same location and observation time. In addition, a tool to visualize meteorological data after 1980 on a map is also available.