UAV Measures Olympic Smog

Perhaps one of the most spectacular Olympic venues, Beijing is also marred by some of the world’s worst air pollution. While perched on a global stage, Beijing is being observed by scientists who are gauging how the atmosphere responds when a heavily populated region (around 17.5 million) suddenly curbs its everyday industrial emissions.

Known as the “great shutdown,” Chinese officials have reduced industrial activity by as much as 30 percent and mandated cuts in automobile use by half, hoping to safeguard the health of competing athletes during the games.

To monitor the air quality, scientists are using the Cheju ABC Plum-Monsoon Experiment (CAPMEX), which will include several flights by autonomous unmanned aerial vehicles (AUAVs) that were developed at the Scripps Institution of Oceanography in La Jolla, Calif.

The data-gathering flights will provide scientists with measurements, which are taken by satellites and observatories on the ground. The information will track dust, soot and other pollution aerosols that travel from Beijing and other parts of China in so-called atmospheric brown clouds. For CAPMEX, photonics instruments will be added to the aircrafts' payloads to help calculate the specific contributions of various aerosols to atmospheric heating.

V. Ramanathan, chief scientist of CAPMEX, with several of the AUAVs that are flying over China. (Photo: Scripps Institute of Oceanography)

"Thanks to the concern of Olympic organizers, the Chinese government, and the cooperation of the Korean government, we have a huge and unprecedented opportunity to observe a large reduction in everyday emissions from a region that's very industrially active," said atmospheric scientist V. Ramanathan of SIO, the lead investigator of CAPMEX.

"CAPMEX will be the very first UAV campaign in east Asia for air pollution and cloud interaction studies," added CAPMEX field campaign co-lead investigator Soon-Chang Yoon, a researcher at the School of Earth and Environmental Sciences at Seoul National University in Korea. "This will be a very interesting experiment that can never happen again."

"Ramanathan's earlier research on atmospheric brown clouds demonstrated their importance in the polluted regions of the atmosphere," said Jay Fein, National Science Foundation program director for climate dynamics. "CAPMEX takes this work an important step forward with new micro- and nanosensor technologies. These technologies will provide new estimates of solar irradiance, aerosol-cloud interactions, climate forcing and important components of the biogeochemical cycles of the East Asian and western Pacific Ocean region."

Thick smog often obscures the sky over Beijing and nearby regions. As a result, residents are frequently warned to spend as little time as possible outdoors, due to the air pollution. (Photo: NASA)

Satellite and ground observations began on Aug.1, while pre-inspection test flights began on Aug. 9, with the field campaign expected to run through Sept. 30.

"Black carbon in soot is a major contributor to global warming," said Ramanathan. "By determining the effects of soot reductions during the Olympics on atmospheric heating, we can gain much needed insights into the magnitude of future global warming."

Ramanathan's team has revolutionized the gathering of atmospheric data through the use of AUAVs that enable researchers to form dimensional profiles of clouds and other atmospheric masses at relatively low cost.

In previous studies, meteorological data gathered by the aircraft helped demonstrate that atmospheric brown clouds can diminish the solar radiation that reaches Earth's surface, warm the atmosphere at low altitudes and disrupt cloud formation.

With CAPMEX, scientists hope to improve their ability to deliver such assessments of particulate pollution effects more rapidly and enhance their value as a policymaking tool.

Miniaturized instruments on the aircraft measure a range of properties such as the quantity of soot and size of the aerosols upon which cloud droplets form. The instruments also record variables such as temperature, humidity and the intensity of sunlight that permeates clouds and masses of smog.

Other new instruments, such as autoleveling platforms, will enable researchers to improve estimates of how much dimming of sunlight takes place at the ocean surface because of pollution aerosols in the atmosphere.

CAPMEX is funded by the National Science Foundation.

For more information, visit: www.nsf.gov