A new long-range, high-altitude jet will track and analyse giant plumes of dust and pollution from Asia as they journey across the Pacific Ocean.
The aircraft is due to take off on its first mission next week carrying researchers who will monitor the plumes, which affect cloud formation and are thought to influence climate change.
The research jet, a Gulfstream-V, will be able to fly to heights over 50,000 feet, far higher than commercial jets typically fly. Instruments on its exterior will monitor plume movement and cloud formation and will also capture dust, pollutants and cloud particles for further study.
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鈥淭his is the first time that an aircraft with very sophisticated instruments will be following these plumes all the way across the Pacific,鈥� says Veerabhadran Ramanathan at Scripps Institution of Oceanography in La Jolla, California, US, a principal researcher on the international team. 鈥淭here is a gold mine of information out there waiting to be uncovered.鈥�
Soot and smog
The plumes are at their greatest each spring when windstorms originating over Central Asia鈥檚 Gobi desert send huge masses of dust mixed with soot and smog from China and other East Asian countries across the Pacific.
The Pacific Dust Experiment, led by researchers at Scripps and the US National Center for Atmospheric Research in Boulder, Colorado, aims to collect data that will shed light on exactly how the plumes affect climate change.
Sulphate particles in the plumes are known to reflect sunlight back into space, shading and cooling the earth in a process known as global dimming. Other particles, known as black carbon, an impure form of carbon formed as a byproduct of the combustion of coal and other fuels, absorb the sun鈥檚 rays and warm the atmosphere.
These particulates can also provide a seed around which clouds can form. Low-elevation clouds rich in water vapour reflect sunlight and cool the climate. However, higher elevation clouds made of ice crystals absorb the sun鈥檚 rays and heat the atmosphere.
Inconclusive reports
Recent reports by the Intergovernmental Panel on Climate Change (IPCC) conclude that the net effect of the Pacific plumes is cooling. But Ramanathan says the reports are inconclusive because previous monitoring flights did not go high enough to observe the tops of the plumes.
鈥淚f a significant amount of black carbon gets caught within the ice crystals of high-elevation clouds, the greenhouse effect could be enormous,鈥� he says.
In March 2007, Ramanathan published a paper based on models and samples collected by plane over North America, which found that the amount of black carbon transported to the continent from Asia is equivalent to 77% of North America鈥檚 own black carbon emissions (Geophysical Research Letters doi:10.1029/2006JD007632).
But Ramanathan says the US is also culpable. 鈥淥ur pollution gets transported across the Atlantic to Europe,鈥� he says. 鈥淲e are all polluting each others鈥� back yards.鈥�
