Gas
and aerosol emissions have been increasing in South East Asia over
the past few years, causing concern to scientists. The region, where
anthropic pollutants combine to form plumes of pollution so complex
that their composition and evolution are as yet not fully understood,
is a laboratory for the study of pollutant transport at a global level.
Measurements of these plumes must be taken not only at ground level,
but also at high altitudes, since polluted air is more likely to travel
farther at altitudes above 10 km.
As
part of a series of international campaigns to improve understanding
of photo-oxidant pollution, NASA has begun experiments to forecast
pollution: Transport and Chemical Evolution over the Pacific (TRACE-P).
The first phase took place between February and March 2001 with the
participation of international research teams, including the "Laboratoire
d'aérologie" (Aerology Laboratory) of Toulouse, in collaboration
with Méteo-France, the French weather-forecasting agency.
This
phase involved observations made by planes containing pollutant measurement
devices. In order for the experiment to succeed, the research planes
had to fly in the pollution plumes. The challenge consisted of guiding
the planes to obtain high quality, relevant data during observations.
The "Laboratoire d'aérologie" of Toulouse played
an essential role. In real time, the team provided digital simulations
of the pollution plumes using MeSoNH, Mesoscale Non-Hydrostatic Model,
a research model used by the European Union to simulate atmospheric
processes.
The
data gathered are currently being analyzed. Initial results confirm
the essential role of the deep continental and oceanic convection,
and of cold fronts, in determining the chemical composition of plumes
of pollution tested above the Pacific Ocean.
