Robot Aircraft to Study Southern California Smog

SAN DIEGO, California, May 7, 2008 (ENS) – Using advanced unmanned aircraft, research scientists at the Scripps Institution of Oceanography, UC San Diego are assessing Southern California’s potential for climate change and better understand the sources of air pollution.

The aircraft typically fly in formations of three, measuring a range of properties such as the quantity and size of the aerosols on which cloud droplets form and the temperature, humidity and the intensity of light that permeates clouds and masses of smog as they go.

The scientists are flying these autonomous unmanned aerial vehicles, AUAVs, from Edwards Air Force Base near Rosamond, California. The study began its first sortie of data-gathering flights on April 2 and will continue through January 2009, offering researchers a chance to view seasonal variations in air pollution.

Known by one of the few acronyms that uses another acronym as one of its letters, the California AUAV Air Pollution Profiling Study, CAPPS, dispatches the AUAVs to fly through clouds and aerosol masses in Southern California, gathering meteorological data.

Scripps Atmospheric and Climate Sciences Professor Veerabhadran Ramanathan, CAPPS’s lead scientist, said Southern California’s dry weather and tendency to trap rather than export smog could make it highly prone to climate change consequences such as accelerated snowmelt and dimming at ground level.

“These monthly UAV flights will provide unprecedented data for evaluating how long range transport of pollutants including ozone, soot and other particulates from the northwest United States, Canada, east Asia and Mexico mix with local pollution and influence our air quality and regional climate including the early melting of snow packs,” said Ramanathan.

V. Ramanathan with three of the unmanned
drone aircraft in the Maldives (Photo
courtesy Scripps Institution of

Ramanathan’s team revolutionized the gathering of atmospheric data in 2006 when the researchers first successfully deployed the unmanned high-tech aircraft in the Maldives AUAV Campaign. It was the first time such comprehensive measurements were made at a cost that was very low relative to traditional manned flights.

The Scripps researchers have used data from the Maldives and other field campaigns to observe that a pervasive mass of air pollution in south and east Asia, often referred to as the “atmospheric brown cloud,” can disrupt rainfall patterns and cause cooling at ground level but warming at higher altitudes.

The cloud typically contains a mix of dust, sulfates and soot and other forms of black carbon – the products of diesel combustion, agricultural biomass burning, use of wood-burning and cow dung-burning stoves in rural homes and the use of coal in home heating.

Ramanathan and his team linked the brown cloud to an observed acceleration of glacial melt in the Himalayas. Himalayan glaciers provide billions of people in Asia with their drinking water.

The CAPPS chief scientist dreams of launching a fleet of drone aircraft to patrol the skies.

In the California AUAV Air Pollution Profiling Study, the Scripps team hopes to determine how much of Southern California’s air pollution comes from Asia, Mexico and from regions north of the state.

“Black carbon and ozone are two major contributors to global warming, next to carbon dioxide,” said Ramanathan. “We hope to document the vertical profiles of black carbon and ozone and their climate warming effects for the first time over California, and this data will likely help California reduce its global warming commitment.”

The California Energy Commission’s Public Interest Energy Research program will employ CAPPS results in an analysis of the potential future economic and ecological consequences of Southern California air pollution.

Scientists also hope to combine CAPPS results with satellite data to better understand the role of aerosols at a larger regional scale.

“As we learn more about the air we breathe and seek solutions to reduce greenhouse gases, this important atmospheric research will help us address the serious challenges to California’s water resources, ecology, and the health of our residents,” said Energy Commissioner Arthur Rosenfeld. “With this study, California continues to demonstrate its commitment as a national leader in climate change research.”

The aircraft will profile atmospheric conditions at altitudes ranging between 2,000 and 12,000 feet and will create a separate file for data collected during wildfires.

Because of Federal Aviation Administration regulations that prohibit unmanned aircraft from flying in public airspace, the flight paths will be limited to military airspace, which is exempted from FAA rules.

The Scripps team hopes to conduct the flights at least once a month or as often as every two weeks.

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